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1
Cui, Zhengshan, Wanxia He, Jun Liu, Wei Wei, Liang Jiang, Jun Huang y Xiaomeng Lv. "Fabrication of polysiloxane-modified polyurethane sponge as low-cost organics/water separation and selective absorption material". Water Science and Technology 74, n.º 8 (9 de agosto de 2016): 1936–45. http://dx.doi.org/10.2166/wst.2016.348.
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Through sol-gel and dip-coating processes, commercial polyurethane sponge modified by polysiloxane was fabricated under low temperature (60 °C) and atmosphere. The contact angle of the obtained polysiloxane/polyurethane sponge is 145 ± 5°. Hence, the polysiloxane/polyurethane sponge could float on water and selectively absorb organics from the surface of the water, indicating simultaneous properties of hydrophobicity and oleophilicity. The absorbent maximum value is 50–150 times of its own weight. The polysiloxane/polyurethane sponge exhibited excellent recyclability, which could be reused by squeezing the sponge due to its high mechanical stability and flexibility. Thermogravimetry-differential thermal analysis test indicated that the polysiloxane/polyurethane sponge exhibited good thermal stability and the stable contact angle of samples tested under increasing temperature indicated its good weather resistance. Due to the commercial property of polyurethane sponge and easy-handling of polysiloxane, the polysiloxane/polyurethane sponge can be easily scaled up to recover a large-area oil spill in water and further work based on the designed equipment has been under consideration.
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Prompawilai, Arisa, Supan Yodyingyong y Darapond Triampo. "Effects of Tetraethyl Orthosilicate on Improving Adhesion Between Polyurethane Sponge/Hydrophobic Silica Gel Composite Materials for Oily Wastewater Treatment". Science of Advanced Materials 12, n.º 2 (1 de febrero de 2020): 200–205. http://dx.doi.org/10.1166/sam.2020.3626.
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The environmental disposal of oily wastewater is a challenge to household and food industries. Cost-effective oil absorbent materials for oily wastewater treatment have been developed by various methods, one of which, the modification with hydrophobic particles. However, the oil absorbents still suffer high cost and low reusability because of the insufficient adhesion between supported material and the hydrophobic particles. Herein, a low cost and simple method to fabricate oil absorbents were reported by immersing commercial polyurethane (PU) sponge in hydrophobic silica gel. The adhesion between hydrophobic silica gel to the 3D surface of PU was assisted with the use of tetraethyl orthosilicate (TEOS) as a silane coupling agent. Only 0.5% TEOS was required for up to 73% improvement of adhered calculated from % silica loading. The use of TEOS showed adhesion enhancement between the surface of PU and the silica which in turn improve reusability. Reusability test mimics the real situation of squeezing the PU/silica sponge to demonstrate good mechanical properties and flexibility. Furthermore, the PU/silica sponge displayed good and rapid absorption capacity. Results from Water Contact Angle (WCA), Scanning Electron Microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) were also used to confirm successful modification of PU with hydrophobic silica gel.
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DIANA-IRINEL, Băilă, Păcurar RAZVAN y Păcurar ANCU?A. "Moisture Absorption Behavior of CP5 Composite Materials Used in Industry". Eurasia Proceedings of Science Technology Engineering and Mathematics 18 (20 de octubre de 2022): 55–63. http://dx.doi.org/10.55549/epstem.1192332.
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In engineering practice, perhaps the most interesting aspect of woodworking deals with the relationship between wood and moisture. The plywood composite presents hygroscopicity characteristic, as the wood and reaction almost like a sponge, will gain or lose moisture from the air based upon the conditions of the surrounding environment. When the tree is in the green state, is first felled, it contains a very large amount of moisture existing in two different forms: as free water that is contained as liquid in the pores or vessels of the wood itself and as bound water, trapped within the cell walls. After that the wood is exposed to the air and immediately loose free water and the wood does not contract or otherwise change in dimension, it is in the state of drying and it is called the fiber saturation point. The moisture content in each piece of CP5 composite material is expressed as a percentage of the weight of the water and oven-dry weight of CP5 composite material. The moisture absorption depends on the wood type, density of wood and it is influenced by the environmental temperature, this is an aspect very important in the furniture industry. The moisture absorption test is generally used for quality control purposes and to measure the degradation of the quality for the wood and composite materials.
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Visco, Annamaria, Antonino Quattrocchi, Davide Nocita, Roberto Montanini y Alessandro Pistone. "Polyurethane Foams Loaded with Carbon Nanofibers for Oil Spill Recovery: Mechanical Properties under Fatigue Conditions and Selective Absorption in Oil/Water Mixtures". Nanomaterials 11, n.º 3 (15 de marzo de 2021): 735. http://dx.doi.org/10.3390/nano11030735.
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Marine pollution due to spillage of hydrocarbons represents a well-known current environmental problem. In order to recover the otherwise wasted oils and to prevent pollution damage, polyurethane foams are considered suitable materials for their ability to separate oils from sea-water and for their reusability. In this work we studied polyurethane foams filled with carbon nanofibers, in varying amounts, aimed at enhancing the selectivity of the material towards the oils and at improving the mechanical durability of the foam. Polyurethane-based foams were experimentally characterized by morphological, surface, and mechanical analyses (optical microscopy observation, contact angle measurement, absorption test according to ASTM F726-99 standard and compression fatigue tests according to ISO 24999 standard). Results indicated an increase in hydrophobic behavior and a good oleophilic character of the composite sponges besides an improved selective absorption of the foam toward oils in mixed water/oil media. The optimal filler amount was found to be around 1 wt% for the homogeneous distribution inside the polymeric foam. Finally, the fatigue test results showed an improvement of the mechanical properties of the foam with the growing carbon filler amount.
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Lettieri, Mariateresa, Maurizio Masieri, Marika Aquaro, Debora Dilorenzo y Mariaenrica Frigione. "Eco-Friendly Protective Coating to Extend the Life of Art-Works and Structures Made in Porous Stone Materials". Coatings 11, n.º 11 (20 de octubre de 2021): 1270. http://dx.doi.org/10.3390/coatings11111270.
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The application of hydrophobic treatments to stone surfaces is the most common proven method to prevent, or at least limit, the degradation of stone-made constructions and artworks brought about by the ingress and action of water, in particular in the case of very porous stone materials. To avoid the use of protective products containing harmful solvents, new green products have been proposed. In this paper, an eco-friendly hydrophobic coating, based on a fluorine polymer dispersed in water, was deeply analyzed to evaluate its protective properties, especially for very porous stone substrates. To this aim, a wide characterization of treated and untreated Lecce stone elements, i.e., a stone typical of the Apulia region, was carried out to assess the optimum required amount, the effectiveness and the protective capability, even against graffiti staining, of the green hydrophobic treatment, still allowing the stone to retain adequate vapor permeability. The efficacy of the eco-friendly product was analyzed also after a short time (four weeks) of outdoor exposure. Suitable performance and short-term durability of the green hydrophobic coating were found, comparable or even greater than those reported in the current literature for other widespread commercial products, confirming the capability of the product to preserve porous stone surfaces even in absence of solvents in its formulation. The study also allowed to experiment with the “contact sponge” test as an appropriate method for evaluating the water absorption properties of the stone.
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Arumugam, Soundhar, Jayakrishna Kandasamy, Ain Umaira Md Shah, Mohamed Thariq Hameed Sultan, Syafiqah Nur Azrie Safri, Mohd Shukry Abdul Majid, Adi Azriff Basri y Faizal Mustapha. "Investigations on the Mechanical Properties of Glass Fiber/Sisal Fiber/Chitosan Reinforced Hybrid Polymer Sandwich Composite Scaffolds for Bone Fracture Fixation Applications". Polymers 12, n.º 7 (6 de julio de 2020): 1501. http://dx.doi.org/10.3390/polym12071501.
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This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications. The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as the inner layers. The composite plate resembles the human bone structure (spongy internal cancellous matrix and rigid external cortical). The mechanical properties of the prepared hybrid sandwich composites samples were evaluated using tensile, flexural, micro hardness, and compression tests. The scanning electron microscopic (SEM) images were studied to analyze the failure mechanism of these composite samples. Besides, contact angle (CA) and water absorption tests were conducted using the sessile drop method to examine the wettability properties of the SF/CTS/epoxy and GF/SF/CTS/epoxy composites. Additionally, the porosity of the GF/SF/CTS composite scaffold samples were determined by using the ethanol infiltration method. The mechanical test results show that the GF/SF/CTS hybrid composites exhibit the bending strength of 343 MPa, ultimate tensile strength of 146 MPa, and compressive strength of 380 MPa with higher Young’s modulus in the bending tests (21.56 GPa) compared to the tensile (6646 MPa) and compressive modulus (2046 MPa). Wettability study results reveal that the GF/SF/CTS composite scaffolds were hydrophobic (CA = 92.41° ± 1.71°) with less water absorption of 3.436% compared to the SF/CTS composites (6.953%). The SF/CTS composites show a hydrophilic character (CA = 54.28° ± 3.06°). The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future.
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Eka Putri, Niken Aprilia, Arif Tjahjono y Perdamean Sebayang. "Analysis of Superhydrophobic-Superoleophilic Properties on Modification of Polyurethane Sponge for Selective Oil-Water Separation". Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics 4, n.º 1 (25 de junio de 2021): 52–62. http://dx.doi.org/10.15408/fiziya.v4i1.19697.
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In this research, a modification of polyurethane (PU) sponge material has been made to obtain superhydrophobic-superoleophilic properties. The PU sponge was coated with several nanomaterials such as ZnO, Fe3O4+TEOS, and stearic acid by dip-coating and drop-coating methods. The tests include selective separation of oil and water with a magnetic response. Several types of oil and organic solvents were tested for absorption capacity. The results showed that the PU@ZnO@Fe3O4@SA sponge has a good absorption capacity, from 4.37 mL to 7.37 mL. The fabricated PU sponge could selectively separate oil from water with a separation efficiency above 99%. The fabricated PU sponge also could be magnetically driven by external magnetic fields. From the characterization using 3D OM, the water contact angle was 153.38°, which indicates that the PU@ZnO@Fe3O4@SA sponge is superhydrophobic. And from surface morphology obtained an average pore size diameter of 167.475 μm.
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Hong, Peng, Zhu Liu, Yang Gao, Yubin Chen, Mingxun Zhuang, Lijuan Chen, Xiaoxuan Liu y Hongping Xiang. "Fabricated of Superhydrophobic Silanized Melamine Sponge with Photochromic Properties for Efficiency Oil/Water Separation". Advances in Polymer Technology 2019 (13 de noviembre de 2019): 1–8. http://dx.doi.org/10.1155/2019/9536320.
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Superhydrophobic sponge as potential absorbing material for oil/water separation is attracting great attention recently. However, there are still some challenges to feasibly fabricate superhydrophobic sponge with large scale and low cost. Herein, a novel photochromic superhydrophobic melamine sponge (PDMS-SP sponge) is fabricated by facilely dip-coating and thermocuring of hydroxyl-terminated polydimethylsiloxanes mixed with photochromic spiropyran. FT-IR, EDS, and XPS results confirm the successful coating of PDMS-SP upon melamine sponge. The resultant sponge not only possesses excellent water repellency with a contact angle of 154.5° and oil-water separation efficiency with an oil absorption capacity of 48–116 folds of itself weight, but also shows photochromic phenomenon between colorless and purple when it is successively exposed to UV irradiation and visible light.
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Vandevoorde, Delphine, Marisa Pamplona, Olivier Schalm, Yves Vanhellemont, Veerle Cnudde y Eddy Verhaeven. "Contact sponge method: Performance of a promising tool for measuring the initial water absorption". Journal of Cultural Heritage 10, n.º 1 (enero de 2009): 41–47. http://dx.doi.org/10.1016/j.culher.2008.10.002.
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Liu, De, Shiying Wang, Tao Wu y Yujiang Li. "A Robust Superhydrophobic Polyurethane Sponge Loaded with Multi-Walled Carbon Nanotubes for Efficient and Selective Oil-Water Separation". Nanomaterials 11, n.º 12 (9 de diciembre de 2021): 3344. http://dx.doi.org/10.3390/nano11123344.
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The influence of different coupling agents and coupling times on the wettability of a polyurethane (PU) sponge surface were optimized. Octadecyltrichlorosilane (OTS) was selected as the optimal coupling agent to prepare the superhydrophobic sponge. The superhydrophobic sponge was prepared in one step, which has the advantages of simple operation and enhanced durability. The superhydrophobic sponge was characterized by scanning electron microscopy, Teclis Tracker tensiometry, and Fourier transform infrared (FT-IR) spectrophotometry. The water contact angle increased from 64.1° to 151.3°, exhibiting ideal superhydrophobicity. Oils and organic solvents with different viscosities and densities can be rapidly and selectively absorbed by superhydrophobic sponges, with an absorption capacity of 14.99 to 86.53 times the weight of the sponge itself, without absorbing any water. Since temperature affects the viscosity and ionic strength of oil, and influences the surface wettability of the sponges, the effect of temperature and ionic strength on the oil absorption capacity of the superhydrophobic sponges was measured, and its mechanism was elucidated. The results showed that the absorptive capacity retained more than 90% of the initial absorptive capacity after repeated use for 10 times. Low-cost, durable superhydrophobic sponges show great potential for large-scale oil-water separation.
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Cheng, Junjie, Jie Hu, Jiawei Wang, Zefei Huang y Baoqian Ye. "A Modified Porous Sponge with Selective Ability for Oil Removal from Oil-Water Mixtures". Adsorption Science & Technology 2022 (12 de abril de 2022): 1–9. http://dx.doi.org/10.1155/2022/4790592.
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As oil and chemical spills pose a significant threat to the water environment, the need to develop efficient sorbent materials to remove oil and organic pollutants from water has arisen. This study aimed to develop a simple modification scheme to impart oil and water selective absorption capacity to a common three-dimensional porous material. Commercially available polyurethane sponges were used as the base material, and vinyl silica aerogel particles were loaded onto the sponges using polydimethylsiloxane as an adhesion agent. As a result, the water contact angle of the modified sponge increased from 118° to 149.2°, and the water absorption decreased from 106.5 g/g to 0.2 g/g; it could absorb oil in oil-water mixtures without absorbing water and maintain an excellent level of selective absorption ability after 20 cycles. This modification scheme is easy to operate and robust and is a scheme of practical application.
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Liu, Chao, Su-Hua Chen, Chi-Hao Yang-Zhou, Qiu-Gen Zhang y Ruby N. Michael. "Application of Nano-Hydroxyapatite Derived from Oyster Shell in Fabricating Superhydrophobic Sponge for Efficient Oil/Water Separation". Molecules 26, n.º 12 (17 de junio de 2021): 3703. http://dx.doi.org/10.3390/molecules26123703.
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The exploration of nonhazardous nanoparticles to fabricate a template-driven superhydrophobic surface is of great ecological importance for oil/water separation in practice. In this work, nano-hydroxyapatite (nano-HAp) with good biocompatibility was easily developed from discarded oyster shells and well incorporated with polydimethylsiloxane (PDMS) to create a superhydrophobic surface on a polyurethane (PU) sponge using a facile solution–immersion method. The obtained nano-HAp coated PU (nano-HAp/PU) sponge exhibited both excellent oil/water selectivity with water contact angles of over 150° and higher absorption capacity for various organic solvents and oils than the original PU sponge, which can be assigned to the nano-HAp coating surface with rough microstructures. Moreover, the superhydrophobic nano-HAp/PU sponge was found to be mechanically stable with no obvious decrease of oil recovery capacity from water in 10 cycles. This work presented that the oyster shell could be a promising alternative to superhydrophobic coatings, which was not only beneficial to oil-containing wastewater treatment, but also favorable for sustainable aquaculture.
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Punyanitya, Sittiporn, Sakdiphon Thiansem, Rungsarit Koonawoot, Watchara Sontichai y Somchart Suchaitanawanit. "Preparation and Characterization of a New Absorbent Pad from Rice Starch". Materials Science Forum 990 (mayo de 2020): 91–95. http://dx.doi.org/10.4028/www.scientific.net/msf.990.91.
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Thisresearch was aimed to studying absorbent pad of adhesive bandage. The absorbent pad made from rice starch composite. This material used for healingprocessofwounds.One component of adhesive bandage is the part contact wound (absorbent pad) that obtained rice starch-based sponge for hemostatic and mixed with povidone-iodine for antibacteria. In this study, we prepared a new absorbent pad from rice starch by lyophilization and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water absortion, Fourier transform infrared spectroscopy (FTIR), and disk diffusion method. The rice strach content of this pad is up to 94 wt%. The diameter of the porous pad was found to be in the range of 10-100 mm. Water absorption of this pad was 6 times of dry weight. The addition of povidone iodine showed good antibiotic resistant microorganism of the rice sponge.
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Ponnamma, Deepalekshmi, Sabari S Nair, Hemalatha Parangusan, Mohammad K. Hassan, Samer Adham, Alamgir Karim y Mariam Al Ali Al-Maadeed. "White Graphene-Cobalt Oxide Hybrid Filler Reinforced Polystyrene Nanofibers for Selective Oil Absorption". Polymers 12, n.º 1 (18 de diciembre de 2019): 4. http://dx.doi.org/10.3390/polym12010004.
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In this work, stable hydrophobic nanocomposites are made from electrospun fibers of polystyrene (PS) containing a hybrid filler combination of (i) hexagonal boron nitride (hBN) and (ii) cobalt oxide (Co3O4) nanomaterials. Good synergistic interaction is observed between the nanomaterials, since the growth of Co3O4 was carried out in presence of white graphene nanosheets. Filler synergy modifies the PS surfaces, by enhancing the filler-polymer interfacial interactions and provides good tensile strength. The hydrophobic films are gamma irradiated to improve crosslinking within the polymer nanocomposites. Since gamma irradiation enhances the surface roughness, its hydrophobicity/oleophilicity increases much and the final nanofibers show good oil-water separation efficiency. The nanofibers act as sponge clothing to skim the oil from a mixture of oil and water. Durability of the fibers in hot water and in presence of ultrasonic waves is also tested and good response is achieved. Contact angle studies are performed to investigate the surface properties and to check the influence of gamma irradiation on the surface wettability. The gamma-irradiated PS nanocomposite fiber shows a contact angle of 152° ± 2° compared to the 140° ± 1° of the neat PS fiber, evidencing the superhydrophobicity. Both the effects of crosslink density enhancement and hybrid filler distribution make the composite fibers stronger in oil absorption application even at higher operation temperatures. The fibers are reported to be robust and durable, in addition.
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Qi, Bowen, Peilong Xu y Chengzhao Wu. "Analysis of the Infiltration and Water Storage Performance of Recycled Brick Mix Aggregates in Sponge City Construction". Water 15, n.º 2 (16 de enero de 2023): 363. http://dx.doi.org/10.3390/w15020363.
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With the gradual advancement of urbanization, urban hardened roofs and pavements are increasing, and the rainwater cycle is being seriously damaged; sponge city construction has become an inevitable trend to address this problem. The analysis of the infiltration and storage performance of recycled brick aggregate, which is highly absorbent and can be used as a permeable paving material in sponge cities, is of great significance. The study firstly designed a simulated rainfall test device, then carried out tests in terms of aggregate gradation, aggregate type, and aggregate grade, and finally analyzed its effect on the void structure and infiltration and water storage performance of recycled brick mix aggregates. The outcomes demonstrate that the particle size of recycled brick concrete aggregate is positively related to the water storage capacity, and the volume water storage rate of recycled sand is close to 26%. The fitting result of 1 h water storage rate under different dosage is 0.984. After 1 h of rainfall, the water storage rate is 3 times that of natural aggregate, and the volume water absorption rate is 2.5 times that of natural aggregate. This indicates that recycled brick concrete aggregate has strong permeability and water storage properties and has great potential for application in sponge city construction, and the study provides a reference for the optimal design of subsequent cities.
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Velkavrh, Igor, Stefan Klien, Joel Voyer, Florian Ausserer y Alexander Diem. "Influence of Water Absorption on Static Friction of Pure and Friction-Modified PA6 Polymers". Key Engineering Materials 799 (abril de 2019): 59–64. http://dx.doi.org/10.4028/www.scientific.net/kem.799.59.
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In the present study, static coefficients of friction of pure and friction modified (FM) polyamide 6 (PA6) polymers against primer-coated steel surfaces were investigated under a series of nominal contact pressures and by considering the influences of water absorption by the polymer, temperature, counter-body surface roughness and lubrication conditions. Under the majority of the test conditions investigated, FM PA6 exhibited lower static friction than pure PA6. Under unlubricated conditions, this was due to the low adhesion of the FM PA6 provided by its friction modifying inclusions; while under lubricated conditions, a combination of softening due to water absorption and decreased adhesion provided by its friction modifiers enabled lower static friction, especially at medium and high contact pressures.
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Kurama, Semra y Elif Eren Gültekin. "Characterization of Silicate Ceramics Using Ultrasonics Test Method". Advances in Science and Technology 92 (octubre de 2014): 194–202. http://dx.doi.org/10.4028/www.scientific.net/ast.92.194.
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Non-destructive testing techniques are widely used for testing ceramic materials. In our studies, two different types of ultrasonic test methods (A-scan and C-Scan) were investigated as non-destructive testing methods for characterization of porcelain tiles. Tiles were sintered in different temperatures to change their porosity and density properties. By changing of ultrasonic time and velocity related with samples’ some physical properties (such as bulk density, apparent density, apparent porosity (%), water absorption (%)) inspected via contact A-scan ultrasonic test method. The results show that without necessity of traditional test methods, some physical properties of ceramics can be determined by using obtained ultrasonic velocity-bulk density, apparent density, apparent porosity (%) and water absorption (%) calibration plots. Additionally, various defects were inspected in samples by using water immersion ultrasonic C-scan method. These results supported this study to obtain the information about defects’ size and place in the ceramic tiles. To support this non-destructive method results scanning electron microscope (SEM) characterization was done and images give the information about the place of the defect.
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Arévalo-Alquichire, Said, Maria Morales-Gonzalez, Luis Diaz y Manuel Valero. "Surface Response Methodology-Based Mixture Design to Study the Influence of Polyol Blend Composition on Polyurethanes’ Properties". Molecules 23, n.º 8 (3 de agosto de 2018): 1942. http://dx.doi.org/10.3390/molecules23081942.
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Polyurethanes are materials with a strong structure-property relationship. The goal of this research was to study the effect of a polyol blend composition of polyurethanes on its properties using a mixture design and setting mathematic models for each property. Water absorption, hydrolytic degradation, contact angle, tensile strength hardness and modulus were studied. Additionally, thermal stability was studied by thermogravimetric analysis. Area under the curve was used to evaluate the effect of polyol blend composition on thermal stability and kinetics of water absorption and hydrolytic degradation. Least squares were used to calculate the regression coefficients. Models for the properties were significant, and lack of fit was not (p < 0.05). Fit statistics suggest both good fitting and prediction. Water absorption, hydrolytic degradation and contact angle were mediated by the hydrophilic nature of the polyols. Tensile strength, modulus and hardness could be regulated by the PE content and the characteristics of polyols. Regression of DTG curves from thermal analysis showed improvement of thermal stability with the increase of PCL and PE. An ANOVA test of the model terms demonstrated that three component influences on bulk properties like water absorption, hydrolytic degradation, hardness, tensile strength and modulus. The PEG*PCL interaction influences on the contact angle, which is a surface property. Mixture design application allowed for an understanding of the structure-property relationship through mathematic models.
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Shen, Xiaojun, Panli Huang, Fengfeng Li, Xiluan Wang, Tongqi Yuan y Runcang Sun. "Compressive Alginate Sponge Derived from Seaweed Biomass Resources for Methylene Blue Removal from Wastewater". Polymers 11, n.º 6 (2 de junio de 2019): 961. http://dx.doi.org/10.3390/polym11060961.
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Low cost fabrication of water treatment polymer materials directly from biomass resources is urgently needed in recent days. Herein, a compressive alginate sponge (AS) is prepared from seaweed biomass resources through a green two-step lyophilization method. This material is much different from conventional oven-, air-, vacuum-dried alginate-based adsorbents, which show limitations of shrinkage, rigidness, tight nonporous structure and restricted ions diffusion, hindering its practical applications, and was used to efficiently remove methylene blue (MB), a main colorful contaminant in dye manufacturing, from wastewater. The batch adsorption studies are carried out to determine the impact of pH, contact time and concentration of dye on the adsorption process. The maximum adsorption capacity can be obtained at 1279 mg g−1, and the shape-moldable AS can be facilely utilized as a fixed-bed absorption column, providing an efficient approach for continuous removal of MB within a short time. It is also important that such a compressive AS can be regenerated by a simple squeezing method while retaining about 70% capacity for more than ten cycles, which is convenient to be reused in practical water treatment. Compressive AS demonstrates its merits of high capability, large efficiency and easy to recycle as well as low cost resources, indicating widespread potentials for application in dye contaminant control regarding environmental protection.
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Hekmati, Amir Houshang, Nabyl Khenoussi, Habiba Nouali, Joël Patarin y Jean-Yves Drean. "Effect of nanofiber diameter on water absorption properties and pore size of polyamide-6 electrospun nanoweb". Textile Research Journal 84, n.º 19 (23 de mayo de 2014): 2045–55. http://dx.doi.org/10.1177/0040517514532160.
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Electrospinning is a common method used to produce nanofiber from almost all types of polymers. By changing effective parameters of this process, especially polymer solution concentration, it is possible to produce nanoweb that consists of nanofibers with different averages of diameter. Here, the effect of nanofibers’ diameter on textural properties (water absorption time and pore size) of polyamide-6 nanoweb has been studied. In this way, three nanowebs with nanofibers’ average diameter of 111, 151, and 318 nm were electrospun from three different concentrations of 15, 20, and 25 wt%, respectively. Contact angle measurement and mercury porosimetry were used to investigate the nanowebs’ water absorption properties and porosity (pore size). The results from the water absorption test demonstrated that the absorption time of a 2 µL water droplet was remarkably shorter for electrospun nanoweb with larger nanofiber diameter. Nanowebs electrospun from 15 and 20 wt% concentrations had roughly the same absorption regime, while for 25 wt% the absorption regime was totally different. Mercury porosimetry of electrospun nanowebs revealed that the pore size in the nanoweb structure decreased by decreasing average diameter of nanofibers. The results of this study showed that contact angle measurement and mercury porosimetry tests could be used as complementary methods to scanning electron microscopy and atomic force microscopy and presented as promising methods to study the textural and physical properties of electrospun nanowebs.
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Losada, Martin, Katherine Mackie, Joseph H. Osborne y Santanu Chaudhuri. "Understanding Nanoscale Wetting Using Dynamic Local Contact Angle Method". Advanced Materials Research 138 (octubre de 2010): 107–16. http://dx.doi.org/10.4028/www.scientific.net/amr.138.107.
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A multiscale quantum/classical-framework for hydrophobicity and UV absorption in heterogeneous coatings is presented. Atomistic water droplet simulations on coated oxide surface are used to define nanoscale contact-angles using a new numerical technique called the dynamic local contact angle (DLCA) method. The DLCA method is well suited to calculate macroscopic contact angles for polymeric and composite coatings. The accuracy of the method is tested for a series of common polymers and composites. In addition, the sensitivity of the contact angles towards functional groups and nanoscale roughness are tested using varying molecular structures. Fluorinated polyhedral oligomericsilsesquioxanes (F-POSS) molecular frameworks are used as a model system. Changes in contact angle and UV absorption spectrum as a function of hydrophobic chain length are calculated to test the feasibility of developing a virtual framework for new coating design connecting atomistic calculations to continuum level material properties.
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Geng, Yongjuan, Shaochun Li, Dongshuai Hou, Xu Chen y Zuquan Jin. "Effect of SiO2 Sol/Silane Emulsion in Reducing Water and Chloride Ion Penetration in Concrete". Coatings 10, n.º 7 (15 de julio de 2020): 682. http://dx.doi.org/10.3390/coatings10070682.
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Here, a new concrete hydrophobic treatment method is developed using SiO2 sol and silane emulsion. The effectiveness of the modification for concrete protection is evaluated through testing water absorption and chloride diffusion. Two types of concrete with different strength grades (C40, C50) are used as the research object. The results show that the water capillary absorption coefficient and chloride ion diffusion coefficient of concrete decrease greatly under the protection of SiO2 sol and silane emulsion. Additionally, the protection effect is better with the increase of SiO2 consumption. Contact angle test results reveal that when the coating amount of SiO2 sol and silane emulsion is 300 g/m2, respectively, the contact angle reaches 150.2°, indicating the concrete (C40) surface reaches the superhydrophobic state. Through scanning electron microscope (SEM) observation, it is found that the hydrophobic effect of the SiO2 sol/silane emulsion is mainly due to the change in the surface morphology of concrete (C40).
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Courard, Luc y Robert Degeimbre. "A capillary action test for the investigation of adhesion in repair technology". Canadian Journal of Civil Engineering 30, n.º 6 (1 de diciembre de 2003): 1101–10. http://dx.doi.org/10.1139/l03-061.
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When repair material is laid down on a concrete substrate, the porosity of concrete allows it to penetrate the substrate, increasing the probability of physical interactions, and subsequently increasing adhesion. Water absorption by immersion or usual capillary action tests do not provide enough information to understand what happens when contact occurs between the concrete substrate and the cement slurries used as a bonding layer. An adaptation of the capillary action test is presented; this is based on a continuous measurement of mass change of the sample. Major differences according to the type of surface preparation are pointed out: absorption rates as well as mass changes are greater for polished concrete substrates than for sandblasted ones. Centrifuged solutions of cement slurries modified with plasticizers and superplasticizers are used for water replacement in the adapted capillary action test. Results clearly show the influence of these admixtures: the greater the adhesion tension, the greater the wetting of the concrete substrate. Determination of these thermodynamic characteristics and performance of an adapted capillary action test provide a better understanding of the mechanisms of interface creation and promotion of adhesion.Key words: concrete, substrate, repair, capillary, absorption, impregnation, interface, centrifugation, superficial tension, pore radius.
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Park, Jang-Hyun y Chang-Bok Yoon. "Properties and Durability of Cement Mortar Using Calcium Stearate and Natural Pozzolan for Concrete Surface Treatment". Materials 15, n.º 16 (20 de agosto de 2022): 5762. http://dx.doi.org/10.3390/ma15165762.
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Applying a concrete surface treatment method (epoxy or primer) can prevent water from penetrating concrete through surface pores. However, if the concrete surface is damaged, the subsequent reconstruction can be expensive and time-consuming. Concrete that is resistant to internal and external water has been extensively developed and used to supplement the surface treatment method. Herein, we prepared specimens by mixing cement mortar with fatty-acid-salt-based calcium stearate attached to two natural pozzolanic materials—diatomite and yellow clay. The physical tests measured (1) the air content, (2) flow test, (3) compressive strength, and (4) activity Factor. Durability experiments were performed on (1) the contact angle, (2) chloride ion diffusion coefficient, and (3) water absorption test. The results revealed that the compressive strength of concrete decreased as the calcium stearate content increased. Furthermore, it was confirmed that the contact angle of the test piece using the pozzolanic substance and calcium stearate was twice as high. It was confirmed that the sand test specimen had the highest water absorption rate, and the DT3% had the lowest. (Sand%: 11.8 > OPC: 6.5 > DT3%: 2.4), the chloride diffusion coefficient also showed similar results. (Sand%: 12.5 > OPC: 8.4 > DT1%: 8.8)Due to its unique insolubility, calcium stearate retards hydrate formation when mixed alone and negates compressive strength loss when combined with pozzolanic mixtures rich in SiO2 and Al2O3. Furthermore, the ideal method for producing water-resistant cement mortar is to evenly disperse calcium stearate in the porous powder of cement mortar.
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Kaplan, Sibel y Selcuk Aslan. "Forearm test for disposable antibacterial foot sweat pads". International Journal of Clothing Science and Technology 28, n.º 3 (6 de junio de 2016): 300–310. http://dx.doi.org/10.1108/ijcst-03-2016-0031.
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Purpose – The purpose of this paper is to obtain thermal sensations arise during skin-antibacterial modified foot sweat pad contact by subjective forearm test carried out on 14 males. Design/methodology/approach – Sweat pads were designed for the foot and topsheet layers, constituting of polypropylene (PP) or polylactic acid (PLA) nonwoven fabrics, were modified by herbal antibacterial agents (cinnamaldehyde, geraniol, phenylethyl alcohol). Antibacterial agents were applied directly or within polymers which prepared by three different polymerization methods. Dry and wet pads (including water 50 percent of absorption capacity) were placed on the forearms of the subjects for a constant period under controlled environmental conditions. Liquid absorption and transfer characteristics of the topsheet layers were measured by standard methods (drop, absorption capacity, wetback tests) and moisture management tester parameters. Subjective coolness and dampness sensations arise during first touch of the pads were gathered and results were discussed according to liquid absorption and transfer characteristics of the sweat pads which differ according to topsheet fabrics and different antibacterial treatments. Findings – The paper showed that, direct or polymerization-based antibacterial applications created significantly different coolness and dampness sensations when compared with raw PP and PLA fabrics. Significant relationships were obtained between coolness sensation and both dampness sensation and absorption capacity results. Originality/value – Forearm test is normally applied on standard fabrics but in this study, it was applied on a disposable product which is used within foot clothing system.
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Ma, Qingwen y Sihan Liu. "Effect on Silt Capillary Water Absorption upon Addition of Sodium Methyl Silicate (SMS) and Microscopic Mechanism Analysis". Coatings 10, n.º 8 (24 de julio de 2020): 724. http://dx.doi.org/10.3390/coatings10080724.
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Silt has the characteristics of developed capillary pores and strong water sensitivity, and capillary water is an important factor inducing the erosion and slumping of silt sites. Therefore, in order to suppress the effect of capillary water, this article discusses the improvement effect of sodium methyl silicate (SMS) on silt. The effect was investigated by capillary water rise testing and contact angle measurement, and the inhibition mechanism is discussed from the microscopic view by X-ray diffraction (XRD) testing, X-ray fluorescence (XRF) testing, scanning electron microscope (SEM) testing and mercury intrusion porosimetry (MIP) testing. The results show that SMS can effectively inhibit the rise of capillary water in silt, the maximum height of capillary rise can be reduced to 0 cm when the ratio of SMS (g) to silt (g) increases to 0.5%, and its contact angle is 120.2°. In addition, considering also the XRD, XRF, SEM and MIP test results, it is considered that SMS forms a water-repellent membrane by reacting with water and carbon dioxide, which evenly distribute on the surface of silt particles. The membrane reduces the surface energy and enhances the water repellence of silt, and combines with small particles in the soil, reduces the number of 2.5 μm pores and inhibits the rise of capillary water.
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Yorseng, Krittirash, Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai y Suchart Siengchin. "Influence of Accelerated Weathering on the Mechanical, Fracture Morphology, Thermal Stability, Contact Angle, and Water Absorption Properties of Natural Fiber Fabric-Based Epoxy Hybrid Composites". Polymers 12, n.º 10 (30 de septiembre de 2020): 2254. http://dx.doi.org/10.3390/polym12102254.
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Epoxy-based biocomposites are a good alternative for metals in lightweight applications. This research has been focused on the effect of accelerated weathering on the mechanical, thermal, contact angle, and water absorption behavior of neat epoxy, individual kenaf and sisal, and kenaf/sisal hybrid epoxy composites. The composite was fabricated by hand layup method. Among the various composites studied, sisal/kenaf/sisal hybrid epoxy composites showed the best properties and retained the thermo-mechanical properties with the lowest water absorption properties even after the weathering test. Thus, composites with hybridized kenaf and sisal with sisal outer layer are encouraging semistructural materials in outdoor applications.
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Guo, Liyu y Wenju Shan. "Water Source Heat Pump’s Stuck Problems and Solutions". Journal of Physics: Conference Series 2174, n.º 1 (1 de enero de 2022): 012084. http://dx.doi.org/10.1088/1742-6596/2174/1/012084.
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Abstract This paper analyses the water source heat pump’s normal stuck reasons, and test each of them. Identify the main reasons of the stuck pump is pump mechanical seal dynamic ring and static ring binding problems. (Poor water quality, water calcium carbonate, magnesium carbonate grind through the dynamic and static ring, after a long time stop, static ring long force extrusion contact, static ring binding surface molecular diffusion migration adhesion), due to the two rings’ binding, rotating torque beyond the motor starting torque, make the motor can’t start normally. This paper aims to find the real cause of the dynamic ring absorption, and put forward subsequent rectification measures to prevent recurrent stuck.
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Wei, Zhou, Naila Arshad, Muhammad Sultan Irshad, Muhammad Idrees, Iftikhar Ahmed, Hongrong Li, Hummad Habib Qazi, Muhammad Yousaf, Lina Abdullah Alshahrani y Yuzheng Lu. "A Scalable Prototype by In Situ Polymerization of Biodegradables, Cross-Linked Molecular Mode of Vapor Transport, and Metal Ion Rejection for Solar-Driven Seawater Desalination". Crystals 11, n.º 12 (1 de diciembre de 2021): 1489. http://dx.doi.org/10.3390/cryst11121489.
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Water scarcity in mass populated areas has become a major global threat to the survival and sustainability of community life on earth, which needs the prompt attention of technological leadership. Solar evaporation has emerged as a renewable energy resource and a novel technique for clean water production and wastewater treatment. Indeed, mounting a scalable solar evaporator including high evaporation efficiency and thermal management remains a significant challenge. Herein, we demonstrate a self-floatable, ecofriendly polypyrrole/wood sponge-based (PPy@WS) steam generator. The low-cost and easy to fabricate evaporator system consists of a single-step in situ polymerization of a 2-D (two-dimensional) hydrophilic wood sponge abundantly available for commercialization. The as-prepared PPy@WS solar evaporator exhibits excellent wettability and is super hydrophilic (contact angle ∼ 0), salt-resistant, and has an excellent light absorption of ∼94% due to omnidirectional diffusion reflection in PPy Nanoparticles (NPs). The capacity of the PPy@WS evaporator to absorb broadband solar radiation and convert it into thermal energy has enabled it to achieve excellent surface temperature (38.6 °C). The accumulated heat can generate vapors at the rate of 1.62 kg·m−2·h−1 along with 93% photothermal conversion efficiency under one sun (1 kW·m−2). Moreover, the presented prototype possesses the capability to be installed directly without the use of any complex protocol to purify seawater or sewage with an efficient rejection ratio of primary metal ions present in seawater (approximately 100%). This simple fabrication process with renewable polymer resources and photothermal materials can serve as a practical model towards high-performance solar evaporation technology for water-stressed communities in remote areas.
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Madruga, Francisco J., Stefano Sfarra, Stefano Perilli, Elena Pivarčiová y José M. López-Higuera. "Measuring the Water Content in Wood Using Step-Heating Thermography and Speckle Patterns-Preliminary Results". Sensors 20, n.º 1 (6 de enero de 2020): 316. http://dx.doi.org/10.3390/s20010316.
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The relationship between wood and its degree of humidity is one of the most important aspects of its use in construction and restoration. The wood presents a behavior similar to a sponge, therefore, moisture is related to its expansion and contraction. The nondestructive evaluation (NDE) of the amount of moisture in wood materials allows to define, e.g., the restoration procedures of buildings or artworks. In this work, an integrated study of two non-contact techniques is presented. Infrared thermography (IRT) was able to retrieve thermal parameters of the wood related to the amount of water added to the samples, while the interference pattern generated by speckles was used to quantify the expansion and contraction of wood that can be related to the amount of water. In twenty-seven wooded samples, a known quantity of water was added in a controlled manner. By applying advanced image processing to thermograms and specklegrams, it was possible to determine fundamental values controlling both the absorption of water and the main thermophysical parameters that link the samples. On the one hand, results here shown should be considered preliminary because the experimental values obtained by IRT need to be optimized for low water contents introduced into the samples. On the other hand, speckle interferometry by applying an innovative procedure provided robust results for both high and low water contents.
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Zhang, Zhaohua, Xiangning Tang, Yunyi Wang, Jun Li, Miao Tian y Ping Xiao. "Effect of Fiber Type, Water Content, and Velocity on Wetness Perception by the Volar Forearm Test: Stimulus Intensity Test". Perception 48, n.º 9 (24 de julio de 2019): 862–81. http://dx.doi.org/10.1177/0301006619863264.
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To investigate the effect of heat, moisture transfer, and mechanical tactile properties of fabrics on skin wetness perception when fabrics were in dynamic contact with skin at three velocities, nine knitted fabrics varying in fiber composition, thickness, and surface texture were evaluated by 20 participants using a wetness rating scale. The objective physical properties of the fabrics, namely, heat and moisture transfer and surface texture, and human physiological responses, namely, skin cooling rate and myoelectric signals, under various conditions were measured, and their correlations with the subjective wetness perception were studied. While the results indicated a significant influence of fabric type, water content, and velocity on skin wetness perception, no significant relation between electromyography and wetness perception was found. Fabrics with faster water spreading speeds and lower absorption rates were perceived as less wet, and the maximum transient thermal flow and skin cooling rate had a significant positive correlation with wetness perception. Furthermore, subjective wetness perception was predicted by the physical parameters of the fabric, that is, maximum transient thermal flow, water content, and friction coefficient, with an acceptable goodness of fit ( R2 = 0.82, p < .001).
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Luna, Carlos Bruno Barreto, Edson Antonio dos Santos Filho, Danilo Diniz Siqueira, Edcleide Maria Araújo, Emanuel Pereira do Nascimento y Tomás Jeferson Alves de Mélo. "Influence of Small Amounts of ABS and ABS-MA on PA6 Properties: Evaluation of Torque Rheometry, Mechanical, Thermomechanical, Thermal, Morphological, and Water Absorption Kinetics Characteristics". Materials 15, n.º 7 (29 de marzo de 2022): 2502. http://dx.doi.org/10.3390/ma15072502.
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In this work, polyamide 6 (PA6) properties were tailored and improved using a maleic anhydride-grafted acrylonitrile-butadiene-styrene terpolymer (ABS-MA). The PA6/ABS-MA blends were prepared using a co-rotational twin-screw extruder. Subsequently, the extruded pellets were injection-molded. Blends were characterized by torque rheometry, the Molau test, Fourier transform infrared spectroscopy (FTIR), impact strength, tensile strength, Heat Deflection Temperature (HDT), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Contact Angle, Scanning Electron Microscopy (SEM), and water absorption experiments. The most significant balance of properties, within the analyzed content range (5, 7.5, and 10 wt.%), was obtained for the PA6/ABS-MA (10%) blend, indicating that even low concentrations of ABS-MA can improve the properties of PA6. Significant increases in impact strength and elongation at break have been achieved compared with PA6. The elastic modulus, tensile strength, HDT, and thermal stability properties of the PA6/ABS-MA blends remained at high levels, indicating that maleic anhydride interacted with amine end-groups of PA6. Torque rheometry, the Molau test, and SEM analysis suggested interactions in the PA6/ABS-MA system, confirming the high properties obtained. Additionally, there was a decrease in water absorption and the diffusion coefficient of the PA6/ABS-MA blends, corroborating the contact angle analysis.
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Ma, Zheng Lu, Jui Chin Chen, Chi Hui Tsou, Yan Mei Wang, Xin Yuan Tian y Chen Gao. "Mechanical Properties and Hydrophilicity of High-Density Polyethylene/Attapulgite Composites". Materials Science Forum 1047 (18 de octubre de 2021): 3–8. http://dx.doi.org/10.4028/www.scientific.net/msf.1047.3.
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High-density polyethylene (HDPE) is used as the matrix and attapulgite (ATT) is used as the reinforcing phase. HDPE/ATT nanocomposites are prepared by melt blending. The effect of ATT content on the mechanical properties, water absorption and morphology of HDPE/ATT composites was studied. The results show that adding a small amount of ATT can improve the mechanical properties of HDPE, but excessive addition will reduce the mechanical properties of HDPE. The water absorption and contact angle test results show that as the ATT content increases, the composite material becomes more and more hydrophilic. After joining ATT, the performance of HDPE / ATT composite material has a significant improvement effect, and it is believed that it will have broad application prospects in the future.
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Mhd Ramle, Sitti Fatimah, Aqilah Abdul Rahim, Nur Hafizzah Jusoh, Nurul Fazita Mohammad Rawi y Che Ku Abdullah Che Ku Alam. "Analysis on the barrier properties of thin film PLA/PBAT reinforced with microcrystalline cellulose". Journal of Physics: Conference Series 2129, n.º 1 (1 de diciembre de 2021): 012059. http://dx.doi.org/10.1088/1742-6596/2129/1/012059.
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Abstract In recent times, awareness on plastic pollution had increase which brings innovation on new productions to be environmental friendly. Various polymers has been used to analyse the suitability to produce thin films. In this study, Poly lactic acid (PLA) and Polybutylene adipate terephthalate (PBAT) reinforced with microcrystalline cellulose (MCC) were investigated. MCC were produced from selected bamboo for obtaining cellulose, then followed by an acidic hydrolysis process for the processing of microcrystalline cellulose (MCC). In this study, the thin film are focusing on the barrier properties such as water absorption, solvent resistance and absorption test. From the results shows that, the lowest rate of water absorption rate is 1.9% by 1% B-MCC/PLA/PBAT, meanwhile, the highest rate of water absorption is 60.1% by 5% C-MCC/PLA/PBAT. The water absorption rate decrease gradually with the decreasing of amount of MCC in the samples. Lastly, the thin film samples can resist with oleic acid solvents as the condition of thin film samples is still remain but they were not resistance with xylene as the thin film samples were shrinked and degraded. This thin film have a potential to replace the non-biodegradable petrochemical polymer based on their properties such as food contact, availability and cost.
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Liu, Feng, Zhengxin Gao, Deli Zang, Chengyu Wang y Jian Li. "Mechanical stability of superhydrophobic epoxy/silica coating for better water resistance of wood". Holzforschung 69, n.º 3 (1 de abril de 2015): 367–74. http://dx.doi.org/10.1515/hf-2014-0077.
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Abstract A three-step procedure has been developed for superhydrophobic coating on wood based on epoxy/silica materials in combination with hydrophobization. First, the epoxy resin is adhered to wood by immersing the samples into an epoxy resin acetone solution, then amino-functionalized silica particles are anchored by the epoxide groups, and finally, the created surface is modified by octadecyltrichlorosilane (OTS). The superhydrophobic surface not only is water repellent, as shown by the contact angle (CA) tests, but also decreases essentially the wood’s water absorption as determined by a 120-day water immersion test. The good mechanical stability of the coating was confirmed by a sand collision method.
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Prastuti, Okky Putri, Ayu Tri Septianingrum, Elisya Dianty Fatmala, Ufafa Anggarini, Tri Eddy Susanto y Nuvixca Dewi Milangsari. "THE EFFECT OF REVERSE FLOTATION METHOD ON SILICA SAND AS WATERPROOFING MORTAR". Jurnal Sains Materi Indonesia 22, n.º 1 (21 de mayo de 2021): 8. http://dx.doi.org/10.17146/jsmi.2020.22.1.5991.
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THE EFFECT OF REVERSE FLOTATION METHOD ON SILICA SAND AS WATERPROOFING MORTAR. Waterproof fabrication mortar cement by silica sand using reverse flotation silica (RFS) method was evaluated by waterproof absorption coefficient, compressive strength test, attractive test, and contact angle. RFS is used to replace waterproof agent and aggregate mortar to reduce cost. The aims of this experiment are to know the RFS process, the ratio between waterproof mortar cement with RFS and mortar, to determine performance and characteristic waterproof mortar cement. Methods used are prepared RFS, mortar cement fabrication, and testing (compressive strength, tensile strength, permeability, contact angle, XRF, FTIR, SEM, BET). Variable used are ratio cement/silica sand, concentrations of CaCl2, curing time, oleic acid, and sodium oleate addition. Optimum collector addition is obtained by oleic acid with compress strength 167.65 kg/cm2, tensile strength 0.16 MPa, permeability 4.6 cm, and contact angle 95°. Curing inside water effect and outside temperature give compress strength 167.65 kg/cm2 and 163.24 kg/cm2, permeability curing inside the water and outside temperature are 4.6 cm and 12 cm. Optimum CaCl2 addition is gained at CaCl2 1.8M with compress strength 64.29 kg/cm2, tensile strength 0.15 MPa, permeability 2.4 cm, contact angle 95°. Optimum ratio cement/RFS is 1:1 with compress strength 167.65 kg/cm2, tensile strength 0.16 MPa, permeability 4.6 cm, and contact angle 950.
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Bátori, Veronika, Mostafa Jabbari, Rajiv K. Srivastava, Dan Åkesson, Patrik R. Lennartsson, Akram Zamani y Mohammad J. Taherzadeh. "Synthesis and characterization of maleic anhydride-grafted orange waste for potential use in biocomposites". BioResources 13, n.º 3 (15 de mayo de 2018): 4986–97. http://dx.doi.org/10.15376/biores.13.3.4986-4997.
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The purpose of the study was to develop a less hydrophilic, and therefore more useful, material from orange waste produced in large quantities by the food industry. A new derivative of industrial orange waste was synthesized via esterification with maleic anhydride. The reaction was confirmed via Fourier transform infrared spectroscopy (FTIR), and the degree of substitution of the hydroxyl groups was 0.39 ± 0.01, as determined by a back-titration method. A major change in physical structure was confirmed by scanning electron microscopy (SEM). The flake-like structure of orange waste changed to a sponge-like structure after the reaction, which involved an increased volume and a reduced density by approximately 40%. The sponge-like structure was represented as an agglomeration of particles with a low specific surface area of 2.18 m2/g and a mean pore diameter of 10.7 nm. Interestingly, the grafted orange waste seemed to become more hydrophobic, which was confirmed by a contact angle test; however, the material absorbed more water vapor. Thermogravimetric analysis (TGA) confirmed a thermally more uniform, though, less heat-resistant material. This work suggests a possible way of utilizing orange waste via synthesizing a renewable material with possible applications as a filler in biocomposites.
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Członka, Sylwia, Anna Strąkowska, Krzysztof Strzelec, Agnieszka Adamus-Włodarczyk, Agnė Kairytė y Saulius Vaitkus. "Composites of Rigid Polyurethane Foams Reinforced with POSS". Polymers 11, n.º 2 (14 de febrero de 2019): 336. http://dx.doi.org/10.3390/polym11020336.
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Rigid polyurethane foams (RPUFs) were successfully modified with different weight ratios (0.5 wt%, 1.5 wt% and 5 wt%) of APIB-POSS and AEAPIB-POSS. The resulting foams were evaluated by their processing parameters, morphology (Scanning Electron Microscopy analysis, SEM), mechanical properties (compressive test, three-point bending test and impact strength), viscoelastic behavior (Dynamic Mechanical Analysis, DMA), thermal properties (Thermogravimetric Analysis, TGA, and thermal conductivity) and application properties (contact angle, water absorption and dimensional analysis). The results showed that the morphology of modified foams is significantly affected by the type of the filler and filler content, which resulted in inhomogeneous, irregular, large cell shapes and further affected the physical and mechanical properties of resulting materials. RPUFs modified with APIB-POSS represent better mechanical and thermal properties compared to the RPUFs modified with AEAPIB-POSS. The results showed that the best results were obtained for RPUFs modified with 0.5 wt% of APIB-POSS. For example, in comparison with unfilled foam, compositions modified with 0.5 wt% of APIB-POSS provide greater compression strength, better flexural strength and lower water absorption.
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Hakim, Yusuf Zaim, Yoki Yulizar, Adi Nurcahyo y Magun Surya. "Green Synthesis of Carbon Nanotubes from Coconut Shell Waste for the Adsorption of Pb(II) Ions". Acta Chimica Asiana 1, n.º 1 (10 de enero de 2018): 6. http://dx.doi.org/10.29303/aca.v1i1.2.
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Numerous complex methods have been developed for the preparation of carbon nanotubes (CNT) such as laser vaporization, arc discharge, pyrolysis, and chemical vapour deposition (CVD). In this study, an environmentally friendly and convenient method called one-step water assisted (quenching) synthesis method was conducted from graphite flakes, which were taken from coconut shell wastes to produce carbon nanotubes. Chemical and physical structure of the carbon nanotubes were characterized by FTIR (Fourier Transform Infrared), Scanning Electron Microscope (SEM), and Transmission Electron Microscopy (TEM). Adsorption performance of heavy metals Pb(II) ions by CNTs has been evaluated using the stirring method, and the concentration of Pb(II) ions has been determined using Atomic Absorption Spectroscopy (AAS). The adsorption conditions such as pH and contact time have been obtained. The results showed that carbon nanotubes were a bit successfully formed, in which the tubes distribution are scattered irregularly. The average tube diameter was 123 nm. During the adsorption test, it was found that the adsorption was proportional to the contact time, in which the optimum contact time was 20 minutes. The optimum pH of Pb(II) ions absorption was 5 where the potential for Pb(II) ions absorption was 120 %. The results indicate the true potential of this green chemistry based method, and it opens the chance for possibility to produce carbon nanotubes at a larger scale.
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Jeffery, Christopher A. "Assessment of Model Error in Limited-Area Simulations of Shallow Water Test Cases on the C-Grid Plane and Sphere". Monthly Weather Review 144, n.º 10 (octubre de 2016): 3591–610. http://dx.doi.org/10.1175/mwr-d-12-00279.1.
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A suite of limited-area test cases for the solution of the shallow water (SW) equations on the plane and sphere is collected and evaluated using the Model for Prediction Across Scales (MPAS) modeling system. Included are regional simulations of standard test cases, as well as new viscous and linearized test cases with exact analytic solutions. Four different aspects of model error are isolated and thereby assessed: 1) error generated by grid nonuniformity on the plane and sphere, 2) time-independent (balanced) error and time-dependent (propagating wave) error, 3) lateral boundary implementation error, and 4) error reduction due to a viscous equation set or an absorbing sponge layer. Results show that the nature of model error for these test cases is specific to the geophysical regime: SW flows on a rotating sphere with Froude numbers of O(0.1) and Rossby numbers also of O(0.1). For SW simulations in this context, inward reflection of gravity waves at the domain boundary does not appear to be a driver of instability or a determining factor in solution accuracy. This conclusion has important implications for idealized studies that exclude this geophysical regime, in particular one-dimensional studies of lateral boundary conditions for limited-area models and studies of the absorption of linearized gravity waves at domain boundaries using dynamical relaxation. An old debate over the efficacy of dynamical relaxation for a viscous equation set is addressed; MPAS simulations of an SW test case with and without dynamical relaxation support claims that eddy viscosity does not notably improve solution accuracy or stability.
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Grabowska, Kalina Barbara y Marcin Koniorczyk. "Internal hydrophobization of cementitious materials by using of organosilicon compounds". E3S Web of Conferences 172 (2020): 14006. http://dx.doi.org/10.1051/e3sconf/202017214006.
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The low resistance to harmful acting of water confined in porous, cement-based materials is a negative feature. As the consequence of porous structure these materials have not sufficient resistance as some physical and chemical detrimental factors. The objective of this paper was to evaluate the impact of organosilicon admixture based on silane and siloxane on physical properties of cement mortar. Internal hydrophobization can significantly improve the durability of a cement materials. At this paper the results of mechanical strength, absorbability and capillary water absorption of internally hydrophobized cement mortar are presented. In addition, a contact angle test was used to assess the changes in wetting angle of cement paste.
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Kalbe, K., A. Annuk, A. Ruus y T. Kalamees. "Experimental analysis of moisture uptake and dry-out in CLT end-grain exposed to free water". Journal of Physics: Conference Series 2069, n.º 1 (1 de noviembre de 2021): 012050. http://dx.doi.org/10.1088/1742-6596/2069/1/012050.
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Abstract This paper presents the results of a series of laboratory tests of CLT end-grain moisture uptake and dry-out. We put CLT test details (TDs) in direct water contact from the end-grain edge and then left the TDs to dry for two weeks in the laboratory and in an outside shelter. Half of the TDs had their wet sides attached to another CLT detail. Fibre saturation point was quickly reached in the bottom part of the TDs during the seven-day water contact. A tendency of increasing moisture content (MC) was up to 90 mm from the wet edges, but we did not record MC levels above the critical level at that height. However, MC exceeded critical levels at 60 mm from the water level. The measured water absorption coefficient Aw was 3.51×10−3 kg/m2-s0’5. Drying was negligible for the TDs which were in contact with another CLT detail. Thus, moisture dry-out is very complicated in joints where the CLT end-grain is covered, such as the exterior wall to foundation or intermediate ceiling connection. The dry-out of CLT is not expected in a cold and humid outdoor environment once the CLT end-grain has absorbed moisture even with wet edges exposed to air.
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Faruoli, M., G. Abbruzzese, RM Di Tommaso y E. Nino. "Visualization of a Small Jet Synthetic Using a Particle Image Velocimetry and Background-Oriented Schlieren Techniques". Journal of Physics: Conference Series 2293, n.º 1 (1 de junio de 2022): 012002. http://dx.doi.org/10.1088/1742-6596/2293/1/012002.
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Abstract This work reports the results of experimental investigations carried out on a submerged synthetic jet obtained through the use of a headset speaker piloted with an appropriate sinusoidal signal at a frequency of 380 Hz. The study begins with the construction of a device that, exploiting the well-known transport properties of impacting jets, was able to improve local ventilation and the removal of excess moisture, due to the natural transpiration of human skin in people forced to assume the same position for prolonged periods such as professional drivers; bedridden patients; etc… Subjects are substantially forced to have parts of their own body in contact with fabrics and coverings that hinder the normal conditions of skin transpiration. The experimental activity was first based on the study of the structure of the synthetic jets, then moving on to the creation of a sponge mat equipped with 80 individual jets. On this sponge mat, semi-empirical tests were carried out in order to remove moisture from a fabric soaked in distilled water. The experimental investigations were first carried out using the PIV technique, and, subsequently, the synthetic jet was visualized using the Background-Oriented Schlieren (BOS) technique which allowed to test the presence of the jets, installed directly on the mattress, in a relatively simple and fast way, requiring a very simplified set-up.
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Mrówka, Maciej, Tomasz Machoczek, Paweł Jureczko, Małgorzata Szymiczek, Magdalena Skonieczna y Łukasz Marcoll. "Study of selected physical, chemical and biological properties of selected materials intended for contact with human body". Polish Journal of Chemical Technology 21, n.º 1 (1 de marzo de 2019): 1–8. http://dx.doi.org/10.2478/pjct-2019-0001.
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Abstract The purpose of the conducted study was to analyse new materials intended for contact with the human body in view of their physical, chemical and biological properties. The authors have put to test six commercially available materials, four out of which were composite polyamide 12-based materials, while two were polyurethanes. The examined materials were assessed in terms of the surface. Subsequently, their hardness and biocompatibility were tested. The authors devoted major attention to the tests of absorption and emissivity of water, the pH = 7.4 PBS buffer solution and pH = 4.3 artificial sweat in temperatures of 21°C and 37°C. The results of the tests have confirmed the non-toxicity of all the tested materials and allowed to provide their characteristics in terms of their surface, hardness, as well as absorption and emissivity of various body fluids. Both polyamide 12 and the tested polyurethanes are classified as thermoplastics that may be used in additive technology.
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Fleureau, Jean-Marie, Legowo Wignyodarsono y Moulay-Idriss Zerhouni. "Effect of surfactants on the mechanical properties of a kaolinite in relation to the solid – liquid contact angles". Canadian Geotechnical Journal 25, n.º 4 (1 de noviembre de 1988): 675–83. http://dx.doi.org/10.1139/t88-078.
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A laboratory test program was undertaken to assess the effects of various ionic surfactants on the mechanical and hydric properties of a kaolinite. The tests showed that surfactants, particularly the cationic species, significantly modified the properties of the unsaturated clay (water absorption rate, absorbed water quantity, suction, swelling, etc.); however, the behaviour of the saturated soil was hardly changed. These results were correlated with measurements of the wettability characteristics of thin plates of consolidated clay. An original method, based on the concept of unit work of dewetting, was used to measure the solid – liquid – gas contact angle of the porous and rugose substrate. In the case of the kaolinite mixed with the cationic surfactant, the contact angle reaches 90° (instead of the 49° for the reference system), corresponding to a significant decrease in the soil suction. Such a decrease can explain the results obtained during infiltration and swelling tests. Key words: surfactants, wettability, unsaturated clays, suction.
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Khasanah, Maulida, Anita Dewi Moelyaningrum y Rahayu Sri Pujiati. "Analisis Perbedaan Tanaman Kayu Apu (Pistia stratiotes) sebagai Fitoremediasi Merkuri (Hg) pada Air". Sanitasi: Jurnal Kesehatan Lingkungan 9, n.º 3 (16 de febrero de 2018): 105–10. http://dx.doi.org/10.29238/sanitasi.v9i3.758.
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Amalgamation in the activities of gold processing produces liquid waste containing heavy metals mercury (Hg). Pistia stratiotes is a floating plant that has high adaptability to climate, rapidgrowth rate, and huge nutrients and water absorption.So that, it is possible to be used as phytoremediation plant for absorbing Hg in water. The purpose of this true experiment research wasto analyze the Hg concentration differences between waste water with and without Pistia stratiotes of 300 gr/ 6 l, 400 gr/ 6 l and 500 gr/ 6 weight in 10 days contact time. The data were analyzed by using One Way Anova test at ? = 0,05. The results showed significant differences ofHg levels between control and treatment groups (p<0,05), and 500 gr/6 l Pistia stratiotes weightgave the highest reduction of Hg level in liquid waste, i.e. 77,6 %. It can be concluded that Pistia stratiotes can be used as phytoremediation plant for Hg metal. However, it is necessary todo further research by adding contact times as variable, so that the absorption rate at each timecan be determined.
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Adamopoulos, Fotios G., Evangelia C. Vouvoudi, Dimitris S. Achilias y Ioannis Karapanagiotis. "Fluorosilane Water-Repellent Coating for the Protection of Marble, Wood and Other Materials". Heritage 4, n.º 4 (25 de septiembre de 2021): 2668–75. http://dx.doi.org/10.3390/heritage4040150.
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The preservation of cultural heritage monuments and artifacts requires the development of methods to produce water-repellent materials, which can offer protection against the effects of atmospheric water. Fluorosilanes are a very promising class of materials, as they act as precursors for the formation of low surface energy polymer networks. 1H,1H,2H,2H-perfluorooctyl-triethoxysilane is applied on marble, wood and the surfaces of other materials, such as glass, silicon wafer, brass, paper and silk. According to the measurements of static water contact angles, it is reported that superhydrophobicity and enhanced hydrophobicity are achieved on the surfaces of coated marble and wood, respectively. Hydrophobicity and hydrophilicity were observed on the treated surfaces of the other materials. More important, water repellency is achieved on any hydrophobic or superhydrophobic surface, as revealed by the very low sliding angles of water drops. The study is accompanied by colorimetric measurements to evaluate the effects of the treatment on the aesthetic appearances of the investigated materials. Finally, the capillary absorption test and a durability test are applied on treated wood and marble, respectively.
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Yoon, Chang Bok y Han Seung Lee. "Selection of the Optimum Carrier for Manufacturing Water-Repellent Concrete and Durability Evaluation of Cement Mortar Using It". Applied Sciences 10, n.º 24 (19 de diciembre de 2020): 9097. http://dx.doi.org/10.3390/app10249097.
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The purpose of this experiment was to complement the shortcomings of existing surface treatment methods and to implement water repellency inside concrete to prevent water penetration and improve the durability of concrete. Carriers to provide water repellency were fabricated using fly ash (FA), silica fume (SF), and natural zeolite which are used as admixtures for concrete. They were mixed with cement mortar, tested, and evaluated. The compressive strength of the water-repellent impregnated natural zeolite (ZWR) specimen was 83% of that of ordinary Portland cement (OPC), and its contact angle was found to be 124°. The water penetration test and chloride ion penetration test confirmed that the water absorption and total passing charge were reduced, while the porosity and pore size were improved. For the other specimens, except ZWR, water repellency was judged to be insufficient due to the low fixing ability for the water-repellent’s active ingredient. The results of evaluating the physical performance and durability of cement mortar for the selection of the optimum carrier revealed that powders other than ZWR are not suitable as a material for providing water repellency to concrete.
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Hasnan, Aisyah Nor y Azizah Hanom Ahmad. "Curing Time and Water Repellent Properties of Dammar-Titanium Dioxide Thin Film". Advanced Materials Research 1112 (julio de 2015): 359–62. http://dx.doi.org/10.4028/www.scientific.net/amr.1112.359.
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Dammar plant resin is a local natural resin that can be bled from Dipterocaupacea sp of tree. It can be found abundantly in Malaysia’s tropical forest especially in Sarawak. Dammar and Titanium Dioxide was mixed in a various wt% to produce Dammar-modified Titanium Dioxide coating system. The modified coating systems were then spin-coated onto Aluminium Q-panel as the substrate. Coated Q-panels were left to cure at room temperature. The curing time was evaluated using dust free stage. The addition of Titanium Dioxide into the coating system fastens the curing time taken for the coated Q-panel to be cure. It only took about 11-12 minutes to dry compared to the coating system before the addition of Titanium Dioxide where a quite long duration required, 32 minutes. Contact angle measurement was also carried out in order to determine the wettability of the coating system. The surface coated with dammar-modified titanium dioxide found to be hydrophobic where a quite large contact angle obtained for the sample with 3 wt% of Titanium Dioxide (PDT3). The water droplets actually rest on the coating surface without wetting the surface. Water absorption test was done to strengthen the contact angle results where coated substrate was soaked into distilled water for 24 hours and being weighed before and after soaking. The difference of before and after soaking weigh showed that the coating surface does not absorb that much water where only approximately 0.02% of water being absorbed by the coating system for 3 wt%. It proved that the coating systems applied are hydrophobic.
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Olshanskaya, L. N., M. A. Chernova, O. A. Aref'eva, E. M. Bakanova, E. V. Yakovleva y S. V. Arzamastsev. "Technology of Obtaining Sorbents Based on Metal Dust and Carbonized Biopolymers for Purification of Surface and Waste Water From Oil and Oil Products". Ecology and Industry of Russia 24, n.º 3 (4 de marzo de 2020): 24–28. http://dx.doi.org/10.18412/1816-0395-2020-3-24-28.
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The results on the production of composite magnetosorbents (CMS) based on agricultural wastes (uncontaminated steel gas treatment dust – PGSN, sunflower husk, paraffin) for the treatment of contaminated water from oil and its products and minimizing the environmental impact of petrochemical enterprises are presented. Biotesting at two test sites (crustaceans Daphnia magna and algae Scenedesmus quadricauda) allowed us to establish that PSGN is non-toxic and can be used as a component of magnetosorbents. The resulting materials showed good physicochemical properties. It was shown that CMC have high hydrophobicity – the contact angle of contact was 125–137 degrees; buoyancy of the material for 96 hours did not decrease below 97–99 %; CMC had a low water absorption of 0.132–0.114 g/g. The oil intensity of the sorbents was 6.0 ± 0.15 g/g. Sorption equilibrium was achieved during the first 10–20 minutes contact of the material with oil and oil productsand remained constant. It has been established that the sorption process is influenced by the nature and thickness of the oil product layer. The maximum sorption capacity is achieved with a film thickness of 3.5 ± 0.15 mm.