Статті в журналах з теми "Molding materials Thermal properties"
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1
Hentati, Nesrine, Mohamed Kchaou, Anne-Lise Cristol, Riadh Elleuch, and Yannick Desplanques. "Impact of hot molding temperature and duration on braking behavior of friction material." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 9 (September 9, 2019): 1416–24. http://dx.doi.org/10.1177/1350650119873789.
Повний текст джерелаАнотація:
The manufacturing process of brake materials used for braking applications consists of a succession of steps among which the hot molding has a major impact on properties and performance of materials. In this paper, impact of hot molding temperature and duration on mechanical and thermal properties of friction materials developed with simplified formulation was investigated. Two different hot molding conditions were studied: condition 1 (low temperature associated to long duration) and condition 2 (high temperature associated to short duration). Braking behavior, thermo-mechanical phenomena and wear and friction mechanisms were also investigated. Results indicated that hot molding conditions did not significantly affect mechanical properties and tribological behavior, but they had impact on thermal properties (material molded according to condition 1, material A presented a higher thermal conductivity) and on wear mechanisms involved in the contact. In addition, results revealed that the studied hot molding conditions impacted thermal localization recorded during braking that was denser for the disc rubbed against material B (material molded according to condition 2).
2
Dobránsky, Jozef, and Zigmund Doboš. "Effect of thermal degradation on rheological properties of polymeric materials." MATEC Web of Conferences 299 (2019): 06001. http://dx.doi.org/10.1051/matecconf/201929906001.
Повний текст джерелаАнотація:
The aim of this paper is to monitor the melt volume index of thermoplastic materials and other rheological properties such as shear rate and viscosity. The aim is to compare and assess whether several times ground and subsequently re-melted samples of pure polymer granulate will have the same or similar rheology properties and whether adjustment of the injection molding machine will be required or willneed to reduce or increase production times. Thermo Scientific with HAAKE Meltflow MT software was used to determine the melt flow rate index (MVR) of thermoplastic materials. Based on the melt flow rate (MVR), shear rate and viscosity evaluation, it has been found that, although the selected materials have undergone multiple changes in the rheology of the polymeric materials, there is no problem in the molding process, and MVR does not change significantly. In this case, no changes in the settings of theinjection molding machines and reduction or increase in production times will be necessary. When re-melting the granulate samples, no excess waste was generated, which would then need to be disposed of and the samples could be re-used for further measurement after grinding.
3
Srebrenkoska, Vineta, Gordana Bogoeva-Gaceva, and Dimko Dimeski. "Composite material based on an ablative phenolic resin and carbon fibers." Journal of the Serbian Chemical Society 74, no. 4 (2009): 441–53. http://dx.doi.org/10.2298/jsc0904441s.
Повний текст джерелаАнотація:
In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenol-formaldehyde resin for high temperature application was optimized. The starting raw materials were characterized and molding compounds with different fiber/ /matrix ratios and different fiber lengths were obtained. From the different laboratory samples, molded parts were made by thermo-compression. The basic mechanical and thermal properties of the composites were determined. From the obtained results, the optimal fiber/matrix ratio was determined for a production of molding compound for high temperature application. The molding process of the composite material was optimized and all the parameters for good mechanical properties and high thermal stability of the composite were obtained. Optimization of the composite molding process was performed by the application of a numerical method for a planned experiment, i.e., a full three-factorial experimental design with variance of all three parameters (fiber length, temperature and time of the press cycle) on two levels. The obtained mechanical properties (flexural strength: 247 MPa, modulus: 27.6 GPa, impact resistance: 110 (for test moldings 10 mm?10 mm) and 91 kJ/m2 (for test moldings 15 mm?15 mm)) justified the application of this composite material in the automotive, leisure, military and other industries where high temperature resistance and high mechanical strength is required.
4
Sakurai, Junpei, Mitsuhiro Abe, Masayuki Ando, and Seiichi Hata. "Combinatorial Searching for Ni-Nb-Zr Amorphous Alloys as Glass Lens Molding Die Materials." Key Engineering Materials 447-448 (September 2010): 661–65. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.661.
Повний текст джерелаАнотація:
This paper presents a search for Ni-Nb-Zr amorphous alloys for application as glass lens molding die materials. To efficiently screen candidate materials, we employed the combinatorial method partially to evaluate thermal stability. First, compositionally spread Ni-Nb-Zr libraries were fabricated by combinatorial arc plasma deposition (CAPD). In order to evaluate the high thermal stability, Ni-Nb-Zr amorphous samples in the libraries were annealed at 723K, the molding temperature for glass lens, for various times in vacuum. Phases in the annealed samples were identified by X-ray diffraction. From XRD identification, candidate amorphous samples with high thermal stabilities were screened. Sputtered samples with the same compositions as the candidate amorphous samples were then fabricated. Other desired properties for glass lens molding die materials, such as mechanical strength, machinability and anti-sticking properties, were evaluated. These investigations revealed Ni36Nb39Zr25 to be a suitable material for a new glass lens molding die. This material exhibited a high fracture stress f of 1.3 GPa, good heat resistance, good machinability, and excellent anti-sticking properties to molten glass.
5
Xi, Yong Guang, Tong Jiang Peng, Hai Feng Liu, and Ji Ming Chen. "Preparation and Properties of Expanded Vermiculite/Gypsum Thermal Insulation Boards." Advanced Materials Research 178 (December 2010): 220–25. http://dx.doi.org/10.4028/www.scientific.net/amr.178.220.
Повний текст джерелаАнотація:
In this paper, thermal insulation boards comprising expanded vermiculite and gypsum were manufactured by casting and compression molding methods respectively. The effects of flake size and preparation methods of expanded vermiculite (EV), ratio of calcined gypsum/EV and molding methods on thermal and mechanical properties were discussed. The results indicated that the thermal conductivity (λ) and compressive strength of the boards decreased with the increase of flake size, and increased as the ratio of calcined gypsum/EV rose, and the density of the boards increased linearly with the increasing ratio. Compared to compression molding, casting technique can make insulating materials with higher thermal conductivity, compressive strength, and lower water content. The boards containing EV expanded by microwave chemical method presented a better thermal insulating property (λ=0.091W•m-1•K-1) relative to the ones filled with microwave exfoliated EV (λ=0.107W•m-1•K-1). The prepared materials can be used for heat, acoustical insulation and moisture adjustment.
6
B Vaggar, Gurushanth, S. C Kamate, and Pramod V Badyankal. "Thermal Properties Characterization of Glass Fiber Hybrid Polymer Composite Materials." International Journal of Engineering & Technology 7, no. 3.34 (September 1, 2018): 455. http://dx.doi.org/10.14419/ijet.v7i3.34.19359.
Повний текст джерелаАнотація:
In the current work characterization of thermal properties are find out to the prepared specimens of silicon filler hybrid composite materials (silicon filler glass – fiber chop strand). The specimens were prepared by hand layup followed by compression molding machine by non-heating molding technique. Thermal conductivity (K), Coefficient thermal expansion (CTE) and Thermal gravimetric analysis (TGA) are found by composite slab method and by thermal muffler oven in a laboratory. The guard heater is used to supply heat which is measured by voltmeter and ammeter. Thermocouples are placed between the interface of the copper plates and the specimen of silicon filled hybrid polymer composite material (HPC), to read the temperatures. By the experimental readings it is found that the K of silicon filler hybrid composite material directly proportional to the % of silicon fillers for the different trails. The CTE inversely varies with % of silicon fillers and in thermal gravimetric analysis the failure of material takes place at 300°C for a time of 20 minutes and also reduction in mass of silicon inserted hybrid composite material. From the results it has been concluded that the considerable enhance in thermal conductivity with negligible decrease in CTE and increase in thermal resistivity of hybrid composite materials.
7
Xue, Mao Quan. "Study and Application of Plastic Construction Materials." Applied Mechanics and Materials 99-100 (September 2011): 1117–20. http://dx.doi.org/10.4028/www.scientific.net/amm.99-100.1117.
Повний текст джерелаАнотація:
As new building materials, plastic has light weigh, corrosion resistance, low thermal conductivity, thermal insulation, waterproof, energy-saving, molding convenient, high recycling characteristic, widely used in building materials. According to the research of improving its flame retardancy, strength, thermal insulation, waterproof properties, the application of plastic use in doors and windows, pipeline, building walls and roofs of buildings, etc. were reviewed, and the developing direction was discussed.
8
Lee, Wen-Jau, I.-Min Tseng, Yu-Pin Kao, Yun-Yun Lee, and Ming-Shan Hu. "Synthesis of alcohol-soluble phenol-formaldehyde resins from pyrolysis oil of Cunninghamia lanceolata wood and properties of molding plates made of resin-impregnated materials." Holzforschung 68, no. 2 (February 1, 2014): 217–22. http://dx.doi.org/10.1515/hf-2013-0068.
Повний текст джерелаАнотація:
Abstract Fast pyrolysis oil (Py-oil) from Cunninghamia lanceolata wood was the starting material in preparing alcohol-soluble phenol-formaldehyde (PF) resins. For this purpose, phenol (Ph) and Py-oils were mixed in weight ratios of 50/50, 40/60, and 30/70. The molecular weight distribution, thermal setting behavior, and heat resistance of the set resins were investigated. Albizia falcataria wood powder and cotton paper were impregnated with the resin mixture, and molding plates were produced by hot pressing; their physical, mechanical, and thermal properties were evaluated. The results show that Py-oil blended with Ph is a suitable raw material for preparing alcohol-soluble PF resins, which possess the characteristics of thermal melting and setting. The properties of the molding plates were satisfactory. The static bending strength (>100 MPa) and elastic modulus of the cotton paper-based products fulfill the requirements of CNS 10559 standard. The initial temperature of the thermal degradation of molding plates is >345°C. The performance of the molding plates decreased with increasing ratios of Py-oil.
9
Billah, Md Maruf, Md Sanaul Rabbi, and Afnan Hasan. "A Review on Developments in Manufacturing Process and Mechanical Properties of Natural Fiber Composites." Journal of Engineering Advancements 2, no. 01 (February 3, 2021): 13–23. http://dx.doi.org/10.38032/jea.2021.01.003.
Повний текст джерелаАнотація:
From the last few decades, the study of natural fiber composite materials has been gaining strong attention among researchers, scientists, and engineers. Natural fiber composite materials are becoming good alternatives to conventional materials because of their lightweight, high specific strength, low thermal expansion, eco-friendly, low manufacturing cost, nonabrasive and bio-degradable characteristics. It is proven that natural fiber is a great alternative to synthetic fiber in the sector of automobiles, railway, and aerospace. Researchers are developing various types of natural fiber-reinforced composites by combining different types of natural fiber such as jute, sisal, coir, hemp, abaca, bamboo, sugar can, kenaf, banana, etc. with various polymers such as polypropylene, epoxy resin, etc. as matrix material. Based on the application and required mechanical and thermal properties, numerous natural fiber-based composite manufacturing processes are available such as injection molding, compression molding, resin transfer molding, hand lay-up, filament welding, pultrusion, autoclave molding, additive manufacturing, etc. The aim of the paper is to present the developments of various manufacturing processes of natural fiber-based composites and obtained mechanical properties.
10
Kim, Young Shin, Jae Kyung Kim, and Euy Sik Jeon. "Effect of the Compounding Conditions of Polyamide 6, Carbon Fiber, and Al2O3 on the Mechanical and Thermal Properties of the Composite Polymer." Materials 12, no. 18 (September 19, 2019): 3047. http://dx.doi.org/10.3390/ma12183047.
Повний текст джерелаАнотація:
Among the composite manufacturing methods, injection molding has higher time efficiency and improved processability. The production of composites via injection molding requires a pre-process to mix and pelletize the matrix polymer and reinforcement material. Herein, we studied the effect of extrusion process conditions for making pellets on the mechanical and thermal properties provided by injection molding. Polyamide 6 (PA6) was used as the base, and composites were produced by blending carbon fibers and Al2O3 as the filler. To determine the optimum blending ratio, the mechanical properties, thermal conductivity, and melt flow index (MI) were measured at various blending ratios. With this optimum blending ratio, pellets were produced by changing the temperature and RPM conditions, which are major process variables during compounding. Samples were fabricated by applying the same injection conditions, and the mechanical strength, MI values, and thermal properties were measured. The mechanical strength increased slightly as the temperature and RPM increased, and the MI and thermal conductivity also increased. The results of this study can be used as a basis for specifying the conditions of the mixing and compounding process such that the desired mechanical and thermal properties are obtained.
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Zhang, Shi Chao, Wei Wu, Yu Feng Chen, Liu Shi Tao, Kai Fang, and Xian Kai Sun. "Preparation and Properties of Phase Change Thermal Insulation Materials." Solid State Phenomena 281 (August 2018): 131–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.131.
Повний текст джерелаАнотація:
With the increase of the speed of vehicle, the thermal protection system of its powerplant requires higher insulation materials. Phase change materials can absorb large amounts of heat in short time. So the introduction of phase change materials in thermal insulation materials can achieve efficient insulation in a limited space for a short time. In this paper, a new phase change thermal insulation material was prepared by pressure molding with microporous calcium silicate as matrix and Li2CO3 as phase change material. The morphology stability, exudation and heat insulation of the materials were tested. The results show that the porous structure of microporous calcium silicate has a good encapsulation when the phase transition of Li2CO3 is changed into liquid. And the material has no leakage during use. The thermal performance test also shows that the insulation performance of the material has obvious advantages in the short term application.
12
Egész, Ádám, and László A. Gömze. "Quality Control Methods of Al2O3 Based Ceramic Injection Molding Raw Materials." Materials Science Forum 812 (February 2015): 35–40. http://dx.doi.org/10.4028/www.scientific.net/msf.812.35.
Повний текст джерелаАнотація:
In the illuminant industry, for producing arc tube parts for high intensity discharge lamps the applied method is the ceramic injection molding. The ceramic arc tube parts are made of high purity alumina powder. By producing ceramic parts, one of the most critical step is to optimizing the injection molding process, [1] but first of all we need to know the properties of injection molding raw material, because later the molding process will be optimized for this material, to decrease the amount of cracked ceramics.For producing ceramic arc tube parts (plugs), there are used two different major components for producing injection molding raw material (feedstock): high purity alumina powder as the main component, and an organic paraffin wax as a binder material. It is expressly important to know the material, physical and chemical properties of these components, since mainly these have affect on the homogenity of feedstock, and therefore on the quality of end product. [3]In this research, both of the main components and the moldable raw material was investigated by visual, physical, chemical and thermal methods. As most important and main statement, the researchers found that the dynamic viscosity of the injection molding raw material depends on the used mixer equipment and the applied deformation velocity.Applied analitycal methods were laser granulometry, differential thermal analysis, and rheological analysis.
13
Sattinova, Zamira, Gaukhar Ramazanova, Bakhytzan Assilbekov, and Elmira Mussenova. "Investigation of Thermodynamic Properties of the Slurry of the Molding Process Beryllium Ceramics." Proceedings 2, no. 22 (December 10, 2018): 1391. http://dx.doi.org/10.3390/proceedings2221391.
Повний текст джерелаАнотація:
Obtaining of ceramic fabrications by hot molding from dispersion materials with anomalous physical properties, such as BeO is particularly complicated. In this case, the difficulties of obtaining of quality products were caused firstly by thermal properties of beryllium oxide, in particular, its unique thermal conductivity. Results of experiments and calculations of the mathematical model of the motion and heat exchange of the slurry mass in the annular cavity are presented. The results of experiments and calculations show the process of molding of the slurry in the annular cavity.
14
Contos, Vaclav. "Effect of Variation of Injection Molding Parameters on Static, Dynamic and Thermo-Mechanical Material Properties of Filled Polymer Materials." Materials Science Forum 1020 (February 2021): 181–86. http://dx.doi.org/10.4028/www.scientific.net/msf.1020.181.
Повний текст джерелаАнотація:
A material (polymer + glass fibers) is characterized by its inhomogeneity and anisotropy. This material is subjected an injection molding simulation at first (generally unnewton type of fluid). Then the material is cooled and common structural analysis (static, dynamic and thermal) is performed. The cooled material has dissimilar mechanical properties for each of discrete element. Thus the mechanical properties (after simulation of load) will completely have different values when influence of injection molding is included.
15
Arbeiter, Daniela, K. Schümann, O. Sahmel, T. Eickner, K. P. Schmitz, and N. Grabow. "The effect of thermal treatment on the mechanical properties of PLLA tubular specimens." Current Directions in Biomedical Engineering 2, no. 1 (September 1, 2016): 27–29. http://dx.doi.org/10.1515/cdbme-2016-0009.
Повний текст джерелаАнотація:
AbstractConventional permanent stent systems for vascular applications are associated with long-term risks, such as restenosis and thrombosis. To overcome these limitations, novel approaches using various biodegradable materials for stent construction have been investigated. In this context, thermal treatment of polymer materials is investigated to adjust the mechanical properties of biodegradable stents. In this work polymeric tubular specimens of biodegradable poly(L-lactide) (PLLA) were extruded and subjected to a molding process using different temperatures above glass transition temperature TG. Physicochemical properties of the molded samples were analyzed using DSC measurements and uniaxial tensile tests. The molding process resulted in a weakening of the PLLA tubular specimens with a simultaneous increase in the degree of crystallinity (χ).
16
Sun, Yonggen, Yanhan Fei, Yanchun Wang, Yuhui Jin, Lanjun Du, Yuansheng Cheng, and Zhiming Du. "Preparation and properties of ZrO2-5CrMnMo composites by ceramic injection molding." Materials Express 11, no. 9 (September 1, 2021): 1594–601. http://dx.doi.org/10.1166/mex.2021.2058.
Повний текст джерелаАнотація:
ZrO2-5CrMnMo composites were fabricated by ceramic injection molding in this research. The hardness and wear properties of ZrO2 ceramic layer and 5CrMnMo substrate were investigated. Moreover, physical properties and microstructures of ZrO2 ceramic coatings were studied and the interfaces of composite samples were observed. The results illustrated that the interface was smooth and properly bonded, and it was concluded that the 5CrMnMo substrate ceramic layer could be provided effectively by ZrO2 ceramic coating. Thermal insulation and thermal shock cycle tests were carried out. The heat insulating property of ZrO2 ceramic coating was remarkable, and even better at a high temperature. The composite samples prepared at 1200 °C did not failed until after more than 68 thermal shocks. The main reasons of limiting the application of this composites so far were still the physical and thermodynamic mismatch between ceramics and steel. But the composite samples fabricated by ceramic injection molding showed excellent thermal shock resistance and high bonding strength in this work.
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Pandit, Partha Pratim, Chang Liu, Scott Iacono, Giancarlo Corti, and Yingbin Hu. "Microstructural Characterization and Property of Carbon Fiber Reinforced High-Density Polyethylene Composites Fabricated by Fused Deposition Modeling." Materials 16, no. 1 (December 25, 2022): 180. http://dx.doi.org/10.3390/ma16010180.
Повний текст джерелаАнотація:
As a promising industrial thermoplastic polymer material, high-density polyethylene (HDPE) possesses distinct properties of ease to process, good biocompatibility, high recyclability, etc. and has been widely used to make packaging, prostheses and implants, and liquid-permeable membranes. Traditional manufacturing processes for HDPE, including injection molding, thermoforming, and rotational molding, require molds or post processing. In addition, part shapes are highly restricted., Thus, fused deposition modeling (FDM) is introduced to process HDPE materials to take advantage of FDM’s free of design, no mold requirement, ease and low cost of processing. To improve the mechanical properties (such as stiffness and strength) and thermal resistance of HDPE, carbon fiber (CF) was incorporated into HDPE, and CF-reinforced HDPE composites were successfully fabricated using FDM process. In addition, the effects of CF content on surface quality, microstructure characterizations, tensile properties, dynamic mechanical properties, and thermal properties have been investigated. Experimental results show that an appropriate CF content addition is beneficial for improving surface quality, and mechanical and thermal properties.
18
Tikhomirova, I. N., A. V. Makarov, and Zin Min Khtet . "Thermal insulation materials based on expanded vermiculite and foamed liquid glass." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 8 (October 23, 2020): 41–45. http://dx.doi.org/10.17073/1683-4518-2020-8-41-45.
Повний текст джерелаАнотація:
This article examines the properties of thermal insulation materials made on the basis of expanded vermiculite and a liquid-glass binder obtained by foaming with a gas-forming agent (foaming agent) and volume-cured by chemical reaction with sodium fluorosilicate. The relations between the amount of binder and filler are determined, which make it possible to form products by injection molding and obtain materials with different strength, thermal conductivity and density.
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Kim, C. O., J. S. Park та T. W. Kim. "The effect of molding pressure on the structural and electrical properties of Y1Ba2Cu3O7−δ superconductors". Journal of Materials Research 13, № 8 (серпень 1998): 2067–70. http://dx.doi.org/10.1557/jmr.1998.0290.
Повний текст джерелаАнотація:
Measurements of structural and electrical properties as a function of the molding pressure in Y1Ba2Cu3O7−δ superconductors have been performed to investigate the texturing behavior. The magnitudes of the molding pressure were 0.5 × 103 N/cm2, 1 × 103 N/cm2, 2 × 103 N/cm2, and 4 × 103 N/cm2. As the molding pressure increases, the anisotropy of the crystal structure decreases and the crystal grows preferentially along the c-axis. As the molding pressure increases, since the size of the grain becomes larger due to the decreased porosity, denser textures are formed. This result indicates that the critical current density is improved, resulting in increased thermal stability at higher molding pressure. While the molding pressure does not affect the oxygen mole fraction below 500 °C, increases in the molding pressure have a remarkable effect on the formation of textures and on the onset temperature for the superconducting transition in Y1Ba2Cu3O7−δ. These results indicate that structural and electrical properties in Y1Ba2Cu3O7−δ superconductors are affected by the molding pressure during growth.
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Li, Han, Hong Zhao Xu, Yan Yan Wang, Chang Ling Zhou, Rui Xiang Liu, and Lu Ping Yang. "Preparation and Properties of NZP Family Ceramics." Solid State Phenomena 281 (August 2018): 450–55. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.450.
Повний текст джерелаАнотація:
The matrix of NZP family ceramics is natrium phosphate zirconium (for short, NZP) . NZP family ceramics have the designabolity of thermal expansion coefficient, and the average thermal expansion coefficient can be changed from negative value to positive value by means of composition adjustment, thus obtaining zero thermal expansion ceramics with good thermal shock resistance. With NZP family ceramics the thermal stress can be effectively reduced and the thermal properties of materials can be enhanced.Therefore, NZP family ceramics have become a hot topic in materials science community in recent years.The calcium phosphate zirconium powder was prepared by coprecipitation method, and NZP family ceramics were prepared after pressing molding and pressureless sintering. The results show that the compressive strength of the prepared NZP family ceramics is 199 MPa and the thermal expansion coefficient is-0.5×10-6/°C at sintering temperature of 1100°C.
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Al-Falahi, Ahmad H. M. "Effect of Immersion Mediums on the Structural and Thermal Properties of [EP/Zr02-Y203] Nanocomposites." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 63, no. 3 (November 11, 2020): 147–52. http://dx.doi.org/10.52763/pjsir.phys.sci.63.3.2020.147.152.
Повний текст джерелаАнотація:
This research studies is the effects of the chemical solutions on the structural properties and thermal conductivity of the nanocomposite materials. Samples were prepared via the hand lay-up molding method, using epoxy resin as a matrix and a variety of weight ratios of the nanoceramic powder (Zirconia- Yttria) as a reinforcement material with different weight ratios,using hand lay-up molding method. Distilled water H20 and diluted HCl and Na0H solutions were used as immersion mediums. Surface roughness, granularity cumulating distribution and thermal conductivity were investigated. The results showed an increase in the surface roughness and changes in the granularity cumulating distribution and thermal conductivity that were dependent on the type of immersion medium used, as well as on the addition ratio of Zirconia-Yttria.
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Li, Jing, and Guo Zhong Li. "Study on the Waterproofing Properties of Cement-Based Composite Thermal Insulation Materials." Applied Mechanics and Materials 711 (December 2014): 166–69. http://dx.doi.org/10.4028/www.scientific.net/amm.711.166.
Повний текст джерелаАнотація:
Polystyrene granules (EPS) for lightweight aggregate and cement for cementing material, while adding a variety of additives, were used to prepare cement-based composite thermal insulation materials by the method of vibration molding. The effects of different waterproof agent on water absorption and strength of cement-based composite thermal insulation materials were studied contrastively by adding emulsified stearic acid and emulsified composite waterproofing agent, and the related mechanisms were analyzed. Results showed that the waterproofing effect and strengthen effect of emulsified composite waterproofing agent is superior to emulsified stearic acid, when the content of emulsified stearic acid and emulsified composite waterproofing agent are 5% and 5%, respectively, the 2h, 24h water absorption of samples are 20.59%, 47.64% and 15.53%, 34.53%, the flexural and compressive strength of samples are 0.32MPa, 0.42MPa and 0.35MPa, 0.47MPa.
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Mertol, A. "Stress Analysis and Thermal Characterization of a High Pin Count PQFP." Journal of Electronic Packaging 114, no. 2 (June 1, 1992): 211–20. http://dx.doi.org/10.1115/1.2906420.
Повний текст джерелаАнотація:
A three-dimensional finite element model of a high pin count plastic-quad-flat-pack (PQFP) has been developed by using ANSYS™ finite element simulation code [1]. The model has been used for both thermo-mechanical stress analysis during temperature cycling and thermal characterization of the package under forced air cooling. Parametric studies have been performed on two different molding compounds with and without a drop-in heat spreader. In addition, the model has been simplified by substituting the leadframe and molding compound with a single homogeneous material, reflecting both molding compound and the leadframe thermo-physical properties. Results from the molding compound parametric studies indicate a lower package stress if the molding compound with low thermal expansion coefficient is used. Comparisons of principal and von Mises stresses show that the simplified model, overall, underpredicts the stresses. Although both the simplified and detailed models predict almost the same value for junction-to-case resistance (θJC), calculated values are significantly lower than the measured θJC. In contrast to θJC, the predicted junction-to-ambient resistances (θJA) are in good agreement with the measured data.
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Miryuk, Olga A. "INFLUENCE OF FILLERS ON PROPERTIES OF LIQUID-GLASS COMPOSITIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 12 (December 7, 2019): 51–56. http://dx.doi.org/10.6060/ivkkt.20196212.5915.
Повний текст джерелаАнотація:
The article presents the results of studies of compositions based on sodium liquid glass and technogenic fillers of mineral and organic origin. As fillers materials were used that can affect the rheological properties and thermal transformation of liquid glass. The introduction of fillers increases the viscosity of the liquid glass compositions. To ensure the molding properties of compositions with a structural strength of 0.2 MPa, 65% or more of the filler is required. It was found that the molding properties of the compositions depend on type of filler. The greatest increase in the viscosity of the compositions is provided by the flask, slates combustible and lignite-bauxite, which limit the effect of free and adsorption water in the composition of the liquid glass. The effect of dispersity of fillers on the change in the molding properties of compositions was studied. An increase in the specific surface area of fillers from 350 to 550 m2/kg makes it possible to increase the structural strength of molding mixtures by 10 to 30%. To improve the molding properties of compositions characterized by high porosity, it is suggested to use combined fillers: cullet and organic filler; cullet and mineral filler containing pore-forming component (slates combustible, flask, lignite-bauxite, wastes of ore dressing).
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Jivotkov, Oleg, Vladimir Kotlyar, Grigorii Kozlov, Irina Jivotkova, and A. Kozlov. "Silicate Brick with Reduced Density and Thermal Conductivity." Materials Science Forum 1011 (September 2020): 37–43. http://dx.doi.org/10.4028/www.scientific.net/msf.1011.37.
Повний текст джерелаАнотація:
Modern housing practice involves the widespread use of silicate brick. The main disadvantage of this building material is its high average density, accompanied by high thermal conductivity, which is accompanied by large heat losses through the enclosing walls of buildings and structures. This article discusses the possibility of improving the thermal characteristics of silicate materials through the use of ash microspheres in the production of piece silicate products, which will significantly reduce the thermal conductivity of the manufactured material. Ash microspheres, being a component of ash and slag waste from the thermal power plants, have a number of valuable properties: firstly, very low density, secondly, closed micro porosity, thirdly, chemical and mineralogical composition prone to reactions under conditions of elevated temperatures and pressures. We have studied the chemical and mineralogical composition as well as physical and mechanical properties of ash microspheres, developed the compositions and technological parameters for the silicate materials production. It has been established that the replacement of quartz sand with ash microspheres as part of the molding mass makes it possible to obtain a silicate brick of medium density class 1.0 and strength sufficient to erect load-bearing enclosing products and structures. Compositions of molding materials using a silicate binder and aluminosilicate ash microspheres using the generally accepted methods were developed and the properties of the obtained silicate material and were studied in accordance with the current GOST requirements for the similar materials.
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Yeung, Dickson T. S., and Matthew M. F. Yuen. "Warpage of Plastic IC Packages as a Function of Processing Conditions." Journal of Electronic Packaging 123, no. 3 (December 22, 1999): 268–72. http://dx.doi.org/10.1115/1.1349421.
Повний текст джерелаАнотація:
Variation of processing conditions on warpage prediction of a plastic quad flat package (PQFP) is examined. Thermal mismatch between package constituent materials is the major cause of IC package warpage. To minimize the warpage problem, a thorough understanding of epoxy molding compound (EMC) properties with molding parameters is necessary as EMC is epoxy-based with time and temperature dependent viscoelastic properties. This paper first addressed the thermal characterization of encapsulating material. Degree-of-cure (DOC or β), coefficient of thermal expansion (CTE or α), glass transition temperature Tg, and shear modulus G′ and G of the molded specimens were measured by various thermal analysis techniques. The glass transition temperature was shown to be a good and direct measure of the degree-of-cure. The CTEs (α1 and α2),G′ and G″ were found to be decreasing functions of degree-of-cure. Viscoelastic EMC material models with DOC (i.e., Tg) dependent were formulated. Package warpage predictions against different processing conditions were performed via finite element analyses. Out-of-plane displacement measurements were performed on plastic quad flat package (PQFP) to validate the numerical results. Warpage prediction by the viscoelastic material model was found to agree with the measured data better than the thermoelastic one. For a given cured content, less warpage was found in packages molded at low temperature and longer molding time OR high temperature and shorter molding time.
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Samoylov, V. M., D. A. Budnik, K. A. Tarasov, M. A. Fateeva, N. N. Goncharova, A. V. Nachodnova, V. A. Elchaninova, and A. A. Konuschenkov. "Properties of fiber-filled molding material based on viscose carbon fiber and phenolformaldehyde resin of various types." Plasticheskie massy, no. 11-12 (January 16, 2023): 26–29. http://dx.doi.org/10.35164/0554-2901-2022-11-12-26-29.
Повний текст джерелаАнотація:
A comparative study of the characteristics of two fiber-filled molding materials, which include a discrete carbon viscose fiber as a filler and phenol-formaldehyde resins of the novolac or resol type as a binder, is given. The DTA-DTG characteristics of the initial resins and the physico-mechanical properties of carbon fiber blanks obtained from fiber-filled molding materials of these types by hot compression molding were determined. It has been established that, regardless of the type of phenol-formaldehyde resin, the density, strength characteristics, toughness and thermal conductivity of carbon fiber plastics based on various resins are practically the same. A comparison of the microstructure of the obtained carbon fiber plastics based on various resins showed that in the case of using phenol-formaldehyde resin of the novolac type, a higher degree of orientation of the fiber filaments parallel to the pressing plane is achieved, which is associated with greater fluidity of the initial fiber-filled molding material. In the direction perpendicular to the pressing axis, the chaotic orientation of the fiber filaments is realized.
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Zhang, Yihe, Anzhen Zhang, Zhichao Zhen, Fengzhu Lv, Paul K. Chu, and Junhui Ji. "Red mud/polypropylene composite with mechanical and thermal properties." Journal of Composite Materials 45, no. 26 (May 13, 2011): 2811–16. http://dx.doi.org/10.1177/0021998311401937.
Повний текст джерелаАнотація:
Polypropylene (PP) based composites containing 0, 5, 10, 15, 20, 30, and 50 wt% red mud are granulated by twin-screw extrusion and injection molding. Their mechanical properties such as tensile strength, flexural strength and modulus, impact strength, and thermal properties are determined. After filling with red mud, the flexural strength and modulus, thermal deformation temperature, and Vicat softening temperature increase, whereas the impact strength decreases with increasing red mud contents. The maximum tensile strength is observed from the PP doped with 15 wt% red mud. Scanning electron microscopy (SEM) is used to investigate the dispersion of red mud in the PP matrix.
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Chen, Furong, Yihang Yang, and Hualong Feng. "Regional Control and Optimization of Heat Input during CMT by Wire Arc Additive Manufacturing: Modeling and Microstructure Effects." Materials 14, no. 5 (February 24, 2021): 1061. http://dx.doi.org/10.3390/ma14051061.
Повний текст джерелаАнотація:
Wire arc additive manufacturing (WAAM) of aluminum-magnesium (Al–Mg) ER5356 alloy deposits is accomplished by cold metal transfer (CMT). During the process, the temperature change of the alloy deposits has a great influence on molding quality, and the microstructure and properties of alloy deposits are also affected by the complex thermal history of the additive manufacturing process. Here, we used an inter-layer cooling process and controlled the heat input process to attempt to reduce the influence of thermal history on alloy deposits during the additive process. The results showed that inter-layer cooling can optimize the molding quality of alloy deposits, but with the disadvantages of a long test time and slow deposition rate. A simple and uniform reduction of heat input makes the molding quality worse, but controlling the heat input by regions can optimize the molding quality of the alloy deposits. The thermophysical properties of Al-Mg alloy deposits were measured, and we found that the specific heat capacity and thermal diffusivity of alloy deposits were not obviously affected by the temperature. The microstructure and morphology of the deposited specimens were observed and analyzed by microscope and electron back-scatter diffraction (EBSD). The process of controlled heat input results in a higher deposition rate, less side-wall roughness, minimum average grain size, and less coarse recrystallization. In addition, different thermal histories lead to different texture types in the inter-layer cooling process. Finally, a controlled heat input process yields the highest average microhardness of the deposited specimen, and the fluctuation range is small. We expect that the process of controlling heat input by model height region will be widely used in the WAAM field.
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Dulebová, Ľudmila, Emil Spišák, Branislav Duleba, František Greškovič, and Tomasz Garbacz. "Characterization of Mechanical and Thermal Properties of PP/Mineral Composites." Advanced Materials Research 1025-1026 (September 2014): 241–45. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.241.
Повний текст джерелаАнотація:
The paper presents the impact of the use of fillers on the mechanical properties of composites with polymeric matrix from polypropylene (PP). Two main types of mineral fillers - talc and calcium carbonate - were used for experiments. PP composites of different percentage filler in matrix PP were compounded with twin-screw extruder and then injection molding. Properties of composites were investigated by tensile test and thermal analysis. Tensile strength was performed to determine and compare the mechanical properties of the unfilled PP and filled PP with various percentages of fillers. Thermal analysis by thermogravimetric was performed on the tested materials - weight loss, glass transition temperature, thermal decomposition, melting temperature.
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Budiyantoro, Cahyo. "The Influence of Nano Filler on Thermal and Mechanical Properties of Polypropylene." Materials Science Forum 929 (August 2018): 78–85. http://dx.doi.org/10.4028/www.scientific.net/msf.929.78.
Повний текст джерелаАнотація:
In order to obtain specific properties in the commercial and engineering applications, PP materials are often combined with additives. Filler is one of solid additive type that made of inorganic materials and is generally distinguished by its influence on the mechanical properties of the resulting mixture with the plastic matrix. Filler dimension less than 100 nm is often categorized as a nanofiller and added to plastics with the range of percentage from 1% up to 10%. Various studies have been conducted to know the influence of filler on mechanical properties, but this study is also conducted to investigate the effect of nanofillers on thermal properties of PP material. Thermal properties are very important to know from the stage of design, processing until the end use final product. Most plastic products are made in soft or liquid condition, the melting temperature (melting temperature, Tm) becomes the basis of the processing parameter adjustment. Investigations done by comparing the thermal properties of commercial copolymer PP material (virgin material and injection molding specimen) and PP materials containing nanofiller (virgin material and injection molding specimen) by using Differential Scanning Calorimetry (DSC), while data of mechanical properties was obtained by the tensile test. Both 1st heating and 2nd heating DSC Experiment showed that nanofilled PP need the highest endothermic effect (2.63 W/g and 1.79 W/g), but nanofiller gave no effect on melting temperature to all type of specimens (in the range of 164.3 – 166.3 °C). The elastic modulus of nanofilled PP was around 1486 Mpa, higher than non-filled PP (999 Mpa).
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Guo, Zhouchao, Rui Xu, and Ping Xue. "Study on Preparation of Ultra-High-Molecular-Weight Polyethylene Pipe of Good Thermal-Mechanical Properties Modified with Organo-Montmorillonite by Screw Extrusion." Materials 13, no. 15 (July 27, 2020): 3342. http://dx.doi.org/10.3390/ma13153342.
Повний текст джерелаАнотація:
The study of processing characteristic and property optimization of ultra-high-molecular-weight polyethylene (UHMWPE) pipe is increasingly performed, mainly focusing on difficulties in the melting process and poor thermal-mechanical properties after forming, which have limited the wider engineering application of UHMWPE pipe. In this study, organo-montmorillonite (OMMT)-modified UHMWPE pipe with good thermal-mechanical properties was prepared by screw extrusion molding. First, high-density polyethylene was subjected to fluidity modification so that the screw extrusion molding of UHMWPE pipe was feasible. Then, OMMT-modified UHMWPE pipes under different addition amounts of OMMT were innovatively prepared by extrusion. Furthermore, the effects of the addition amounts of the compatibilizer HDPE-g-MAH and the silane coupling agent γ-(2,3-epoxy propoxy) propyl trimethoxy silane (KH560) on the thermal properties of OMMT-modified UHMWPE pipe were investigated for the first time. Compared with those of pure UHMWPE pipe, the Vicat softening temperature (from 128 to 135.2 °C), thermal deformation temperature (from 84.4 to 133.1 °C), bending strength (from 27.3 to 39.8 MPa), and tensile strength (from 20.8 to 25.1 MPa) of OMMT-modified UHMWPE pipe were greatly increased. OMMT-modified UHMWPE pipe with good thermal-mechanical properties was able to be prepared by extrusion for the first time. The compatibilizer method of HDPE-g-MAH was slightly more effective than the coupling agent method of KH560.
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Suplicz, András, and József Gábor Kovács. "Development of Thermally Conductive Polymer Materials and their Investigation." Materials Science Forum 729 (November 2012): 80–84. http://dx.doi.org/10.4028/www.scientific.net/msf.729.80.
Повний текст джерелаАнотація:
In the recent years a remarkable development can be observed in the electronics. New products of electronic industry generate more and more heat. To dissipate this heat, thermally conductive polymers offer new possibilities. The goal of this work was to develop a novel polymer based material, which has a good thermal conduction. The main purpose during the development was that this material can be processed easily with injection molding. To eliminate the weaknesses of the traditional conductive composites low-melting-point alloy was applied as filler. Furthermore in this work the effect of the filler content on thermal conductivity, on structure and on mechanical properties was investigated.
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Yu, Rui, Shusen Chen, Guanchao Lan, Jing Li, Chenglong Wei, and Shaohua Jin. "Thermal hazards evaluation of insensitive JEOL-1 polymer bonded explosive." Materials Express 9, no. 6 (September 1, 2019): 596–603. http://dx.doi.org/10.1166/mex.2019.1529.
Повний текст джерелаАнотація:
Thermal stimuli is one of the major external stiumuli resulting from an overheated explosion of a munition. In order to evaluate the influence of external thermal stiumuli on the thermal hazards of JEOL-1 (32 wt% octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 32 wt% 3-nitro-1,2,4-triazole-5-one (NTO), 28 wt% Al and 8 wt% binder system) explosive, accelerating rate calorimeter (ARC) is used to study the adiabatic thermal decomposition properties of JEOL-1 molding powders, and the slow cook-off properties of JEOL-1 are studied by experimental test and numerical simulation. The activation energy Ea, pre-exponential factor A, mechanism function f(α) and self-accelerating decomposition temperature (SADT) of adiabatic thermal decomposition of JEOL-1 molding powders are obtained according to ARC results. The response level of JEOL-1 polymer bonded explosive (PBX) columns exposed to an engulfing liquid pool fire is examined by the slow cook-off test. The ignition location, ignition temperature, ignition time and the transient temperature distributions of JEOL-1 PBX columns during the slow cook-off are obtained by numerical simulation. It can be concluded from this study that JEOL-1 is a low vulnerable explosive with high thermal safety.
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Park, Hyung-Pil, Baeg-Soon Cha, Soo-Bin Park, Jae-Hyuk Choi, Dong-Han Kim, Byung-Ohk Rhee, and Kye-Hwan Lee. "A Study on the Void Formation in Residual Wall Thickness of Fluid-Assisted Injection Molding Parts." Advances in Materials Science and Engineering 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/238251.
Повний текст джерелаАнотація:
In fluid-assisted injection molding, the distribution of the residual wall thickness on the inside and outside of the curved area is different, and void is formed due to the effect of the shrinkage on the outside where the residual wall thickness is thicker. The shrinkage that takes place in the residual wall is affected by the rheological changes in the polymer caused by temperature change and also by the thermal properties of the penetration fluid. In this study, the different effects on void formation in residual wall during fluid-assisted injection molding were analyzed, and water and silicone oil that had different thermal properties were used for the fluids. For this, heat transfer analysis and injection molding analysis were conducted. The void formation occurred due to the different temperature distribution and volumetric shrinkage in the direction of the residual wall in the curved area with a hollow section. It was also found that the void formation in the curved area decreased in the case of silicone oil compared to the case of water from simulation and experiments.
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Karácsony, Zs, A. Erős, E. Andersen, and Gy Bánhegyi. "Development of Ceramic Feedstock for Powder Injection Molding." Materials Science Forum 812 (February 2015): 95–99. http://dx.doi.org/10.4028/www.scientific.net/msf.812.95.
Повний текст джерелаАнотація:
As part of our technology development program we started to prepare for introducing ceramic injection molding technology. The technology consists of the following steps: 1. feedstock preparation (mixing the ceramic powder with binding agent), 2. injection molding (green body production), 3. thermal or solvent debinding (brown body production), 4. sintering of the brown body. To make alumina ceramic parts essential to know the properties of all raw materials which are used during the PIM process. That is why this article is focused on the thermogravimetric studies of potential raw materials. These thermogravimetric studies helped to optimize the debinding experiments at specimens with high alumina content. First of all the measured curves of the feedstock were compared with calculated curves from the single raw materials. This comparison helped us to understand the processes in the feedstock during the sintering. Then thermogravimetric experiments in air atmosphere were made to optimize the sintering process. These experiments resulted good structural properties at the sintered parts.
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Erben, Jakub, Katerina Blatonova, Tomas Kalous, Lukas Capek, Lubos Behalek, Martin Boruvka, and Jiri Chvojka. "The Injection Molding of Biodegradable Polydioxanone—A Study of the Dependence of the Structural and Mechanical Properties on Thermal Processing Conditions." Polymers 14, no. 24 (December 16, 2022): 5528. http://dx.doi.org/10.3390/polym14245528.
Повний текст джерелаАнотація:
Recent years have observed a significant increase in the use of degradable materials in medicine due to their minimal impact on the patient and broad range of applicability. The biodegradable polymer Polydioxanone (PDO) provides a good example of the use of such one polymer that can represent the aforementioned medical materials in the field of medicine, due to its high level of biocompatibility and interesting mechanical properties. PDO is used to produce absorbable medical devices such as sutures and stents, and is also suitable for the fabrication of certain orthopedic implants. Polydioxanone can be processed using the injection molding method due to its thermoplastic nature; this method allows for the precise and easily-controllable production of medical materials without the need for toxic additives. A number of small commercial polymer implants have recently been introduced onto the market based on this processing method. It is important to note that, to date, no relevant information on the molding of PDO is available either for the scientific or the general public, and no study has been published that describes the potential of the injection molding of PDO. Hence, we present our research on the basic technological and material parameters that allow for the processing of PDO using the laboratory microinjection molding method. In addition to determining the basic parameters of the process, the research also focused on the study of the structural and mechanical properties of samples based on the thermal conditions during processing. A technological frame work was successfully determined for the processing of PDO via the microinjection molding approach that allows for the production of samples with the required homogeneity, shape stability and surface quality in a laboratory scale. The research revealed that PDO is a polymer with a major share of crystalline phases, and that it is sensitive to the annealing temperature profile in the mold, which has the potential to impact the final crystalline structure, the fracture morphology and the mechanical properties.
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Immonen, Kirsi, Sini Metsä-Kortelainen, Juha Nurmio, Amélie Tribot, Tuomas Turpeinen, Atte Mikkelson, Tomi Kalpio, Otto-Ville Kaukoniemi, and Heli Kangas. "Recycling of 3D Printable Thermoplastic Cellulose-Composite." Sustainability 14, no. 5 (February 25, 2022): 2734. http://dx.doi.org/10.3390/su14052734.
Повний текст джерелаАнотація:
3D printing enables sustainable product innovations through novel design, reduced use of materials, and local manufacturing. Sustainable 3D printing can further be realized using recyclable materials. Cellulose is an abundantly available renewable material. Modified celluloses, such as thermoplastic cellulose esters, are widely used in injection molding applications. The aim of this research was to study the properties of a cellulose-based composite (cellulose acetate propionate (CAP) polymer matrix with 20 wt. % microcellulose) in injection molding and granular extrusion-based 3D printing processes over multiple recycles. The impact of the processing methods on the composite’s properties were investigated. Both injection molded and 3D printed samples were ground with plastic grinding mill to particle sizes below 3 mm after each preparation stage and reused as such in the next process cycle. Morphology, mechanical and thermal properties, and material degradation were analyzed. The thermoplastic cellulose-based compound was found to be directly recyclable for both processes without the need for any additional compounding steps. The polymer matrix was able to withstand at least seven processing cycles without degradation. However, microcellulose was found to be more sensitive to thermal stress. The mechanical and thermal properties of the cellulose-based composites remained close to initial levels throughout.
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Li, Xiao Long, and Guo Zhong Li. "Preparation and Study on the Performance of Glazed Hollow Beads Thermal Insulation Materials." Advanced Materials Research 662 (February 2013): 335–38. http://dx.doi.org/10.4028/www.scientific.net/amr.662.335.
Повний текст джерелаАнотація:
The glazed hollow beads thermal insulation board was made of glazed hollow beads and perlite by selecting cement and fly ash as cementitious materials, and adding appropriate amount of VAE emulsion and fibers, in the compression molding process. In this paper, the influence of different dosages of perlite replacing vitrified beads, VAE emulsion and fiber on the material properties were studied. Besides, the internal morphology of the sample was observed by scanning electron microscopy, and the action mechanism of the insulation material was explored.
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Skubic, Blaž, Mitja Lakner, and Igor Plazl. "Thermal Treatment of New Inorganic Thermal Insulation Board Based on Expanded Perlite." Advanced Materials Research 560-561 (August 2012): 249–53. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.249.
Повний текст джерелаАнотація:
A new lightweight thermal insulation board, containing expanded perlite and inorganic silicate binder with corresponding industrial production procedure was developed. The industrial technology was developed in cooperation between company Trimo d.d. and Faculty of chemistry and chemical technology Ljubljana and among others includes mixing of raw materials, molding, microwave drying and high temperature treatment of the dried board. A new product has low density (130 – 160 kg/m3), good mechanical properties and durability and can be used in various fields where inorganic thermal insulation is required. The current work presents the experimental study of the final process during plate production – high temperature treatment with sintering. During thermal treatment of the board, certain shrinkage is required to obtain sufficient mechanical properties and durability. Controlling the process of high temperature thermal treatment is the key to achieve the right balance between low final density of the board and its good mechanical properties.
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Maramygin, Alexandr. "MODIFIED EPOXY COMPOSITION FOR PRODUCTION OF THERMAL PROTECTION COATING." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 63 (2020): 88–96. http://dx.doi.org/10.15593/2224-9982/2020.63.10.
Повний текст джерелаАнотація:
The material summed up in this article is recommended for engineers of aerospace industry, as well as can be of inter-est for the production personnel. The article covers the production of “scale-like” outer thermal protection coatings on the basis of syntactic materials with tumescent characteristics used in the production of special purpose equipment. The research per-formed sums up the results of the practical implementation of the technology adaptative method in the conditions of the real outer thermal protection coatings production. This work describes a typical technological process of “scale-like” outer thermal protection coating production from the panels based on syntactic material, including the stages of separate panels production with the help of shape-generating molding tools and forming of thermal protection coating by laying and molding-on of separate panels on the pressure restraint layer of the aircraft. The author proves the effectiveness of technology adaptative method us-age on the example of modification processes of pattern polymer composition being the basis of syntactic material. The re-search describes the solutions for the production cycle optimization via improvement of technological properties of the materials used. The work also contains the results of the researches, including spectral and thermochemical analyses of polymer compo-sitions modified by polyisocyanates, and describes the research techniques of their properties. Quasi-eutectic compositions of aliphatic and aromatic amines are received, which, being used as curative of reactive epoxiurethane polymers produced on the basis of epoxy-diane oligomers and polyisocyanates, enable to divide the polymerization process into two stages. The method described in the article provides the elimination of panel defects on the stage of molding-on due to implementation of mode separation in polymerization processes, which contributes towards the quality and reliability of thermal protection coating.
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Tang, Bo, Ying Wang, Li Hu, Lianbin Lin, Chenxi Ma, Chongyin Zhang, Yonggen Lu, Kai Sun, and Xinfeng Wu. "Preparation and properties of lightweight carbon/carbon fiber composite thermal field insulation materials for high-temperature furnace." Journal of Engineered Fibers and Fabrics 14 (January 2019): 155892501988469. http://dx.doi.org/10.1177/1558925019884691.
Повний текст джерелаАнотація:
The main purpose of this work is to make lightweight carbon/carbon fiber composite with low density and low thermal conductivity for high-temperature furnace. Lightweight carbon/carbon fiber composite thermal field insulation materials were prepared by the process method of needle punching—molding curing high-temperature graphitization. The results show that the long carbon fiber in the carbon/carbon fiber composite forms a three-dimensional structure of X-Y-Z with a density of 0.16 ± 0.02 g/cm3, which makes the composite material have excellent thermal insulation performance at high temperature. The thermal conductivity of the carbon/carbon fiber composite at 2000°C is only 0.38 W/(m·K), and the impurity element content is only 19.09 ppm. The method of needle-punching-forming-felt high-temperature graphitization can provide some suggestions for the preparation of the lightweight long carbon fiber composite.
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Jiang, Qing-song, He-sheng Liu, Qing-wu Xiao, Shih-feng Chou, Ai-hua Xiong, and Hua-rong Nie. "Three-dimensional numerical simulation of total warpage deformation for short-glass-fiber-reinforced polypropylene composite injection-molded parts using coupled FEM." Journal of Polymer Engineering 38, no. 5 (April 25, 2018): 493–502. http://dx.doi.org/10.1515/polyeng-2016-0445.
Повний текст джерелаАнотація:
Abstract Based on the effects of natural cooling on the warpage of the injection-molded parts, a concept of total warpage deformation was proposed. A three-dimensional numerical model of total warpage for the injection-molded parts of short-glass-fiber-reinforced polypropylene (PP) composites was established using coupled finite element method (FEM). The total warpage deformation is composed of two parts: stress-induced deformation during injection molding and thermally induced shrinkage deformation after ejection. The residual stress, temperature, and anisotropic thermal and mechanical properties formed in injection molding were subsequently transferred into the thermal stress analysis package as initial conditions. On account of the difference between the fluid and structural mesh, the tetrahedral and hexahedral mesh types were used in injection molding simulation and thermal stress analysis, respectively. The comparison between the simulation and experimental results showed that the simulated warpage deformation agreed well with the experimental measurements quantitatively and qualitatively, suggesting the validation of the proposed numerical model.
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Chandrasekaran, Kailasam, Periyasamy Shanmugam, and Palanisamy Senthilkumar. "Mechanical and thermal properties of cotton-bamboo fabric/glass fiber epoxy composites." Polimery 67, no. 11-12 (January 2, 2023): 567–74. http://dx.doi.org/10.14314/polimery.2022.11.4.
Повний текст джерелаАнотація:
Five-layer epoxy composites consisting of two outer layers made of glass fiber and three inner layers of cotton-bamboo fabric were obtained by compression molding. The influence of glass fiber content (35, 40, 45 and 50 wt%) and the order of stacking laminate layers on the mechanical properties (tensile, flexural, compressive, impact strength), thermal properties (TGA) and structure (FTIR, SEM) of the composites was investigated. The best mechanical and thermal properties were obtained with the content of 45 wt% glass fiber.
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Huang, Zhen, Heyi Ge, Jiaojiao Yin, and Fanggang Liu. "Effects of fiber loading and chemical treatments on properties of sisal fiber-reinforced sheet molding compounds." Journal of Composite Materials 51, no. 22 (December 14, 2016): 3175–85. http://dx.doi.org/10.1177/0021998316683440.
Повний текст джерелаАнотація:
In this study, the effects of fiber loading from 0 vol.% to 15 vol.% and the chemical treatments on the properties of the sisal fiber-reinforced sheet molding compounds were investigated. The chemical treatments were performed with alkali, γ-ammoniapropyl-triethoxy-silane (KH-550) and γ-methacryloxypropyl-trimethoxy-sliane (KH-570), respectively, to improve the interfacial adhesion between sisal fiber and the matrix (unsaturated polyester resin). The changes of surface morphology and sisal fiber functional groups were investigated by scanning electron microscopy and Fourier transform infrared spectroscopic analysis, respectively. Compared to the untreated sisal fiber-reinforced sheet molding compounds, the mechanical property of the treated sisal fiber-reinforced sheet molding compounds increased due to the interfacial enhancement between sisal fiber and the matrix, which could be observed through the scanning electron microscopy images of fracture surface. Moreover, the better interfacial adhesion was also assisted in water absorption resistance and the thermal stability of the treated sisal fiber-reinforced sheet molding compounds. In the chemical treatments, KH-570 treatment was proved to be an effective method to improve the interfacial adhesion between sisal fiber and the matrix.
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Ghoreishy, M. H. R., M. Rafei, and G. Naderi. "OPTIMIZATION OF THE VULCANIZATION PROCESS OF A THICK RUBBER ARTICLE USING AN ADVANCED COMPUTER SIMULATION TECHNIQUE." Rubber Chemistry and Technology 85, no. 4 (December 1, 2012): 576–89. http://dx.doi.org/10.5254/rct.12.88917.
Повний текст джерелаАнотація:
ABSTRACT A previously developed computer simulation technique was extended for the optimization of the molding time of a thick rubber article in which a commercial finite element code was employed in conjunction with an in-house developed subroutine. The kinetics of the rubber-curing reaction and the physical and thermal properties of the materials were determined using appropriate methods. The accuracy of the method was examined by comparison of the measured temperature profile with calculated data. Two cure simulations were carried out. First, the molding time was set to the actual time used in the manufacturing specification. Having checked the distribution of the state of the cure at the center of the rubber, the molding time was reduced to save time, reduce energy, and avoid the risk of overcure at the rubber surfaces. Based on the proposed molding time, a second simulation was performed. A comparison between the hardness of the rubber article made by the reduced molding time and the measured hardness on the article manufactured by the previous molding time showed that there was 5 shore A increase in the hardness, which confirmed the applicability of procedures used in this work.
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Rodrigues, Daniel, Gilberto V. Concílio, Elisa Pinto da Rocha, José A. de Castro, and Marcos F. de Campos. "Thermal Analysis Investigation of NdFeB Bonded Magnets." Materials Science Forum 802 (December 2014): 590–95. http://dx.doi.org/10.4028/www.scientific.net/msf.802.590.
Повний текст джерелаАнотація:
NdFeB bonded magnets are produced by compression molding and curing. Typical raw materials are mixtures of epoxy resin and Nd2Fe14B flakes, produced mostly by melt spinning. The curing temperature should be adjusted for obtaining the best in terms of mechanical properties without overheating the pressed component. High curing temperatures can strongly oxidize Nd, generating more heat, and burning may occurs. The curing reaction is exothermic, thus the actual curing temperature will depend on the cured mass. This paper investigates this heating generation during curing, using DSC experimental apparatus.
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Babashov, V. G., V. V. Butakov, S. G. Kolyshev, and V. G. Maksimov. "RESEARCH OF THE UNEVENNESS OF DISTRIBUTION OF THE STRENGTH PROPERTIES OF HIGH-TEMPERATURE THERMAL INSULATION MATERIALS." Proceedings of VIAM, no. 6 (2021): 123–34. http://dx.doi.org/10.18577/2307-6046-2021-0-6-123-134.
Повний текст джерелаАнотація:
The article considers the results of the study of the uneven distribution of the strength properties of a rigid high-temperature fibrous heat-protective material over the volume of the block. The article presents a comparative study of the uneven strength of two materials that differ in the method of introducing the binder. A conclusion is proposed about the mechanism of the occurrence of unevenness of the strength properties of a rigid fibrous thermal insulation material when a soluble binder is introduced into the material by the strait method. The absence of such a mechanism is shown for materials obtained using a solid-phase binder introduced into the molding hydraulic mass.
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Ma, Long, and Guo Zhong Li. "The Preparation of Red Mud Foam Lightweight Thermal Insulation Material." Applied Mechanics and Materials 541-542 (March 2014): 104–7. http://dx.doi.org/10.4028/www.scientific.net/amm.541-542.104.
Повний текст джерелаАнотація:
Red mud foam lightweight thermal insulation material was prepared by red mud, fly ash, cement as main raw materials, adding a certain amount of adhesive, through ingredients, mixing, molding, foam, sintering process. The influence of the ratio of red mud and fly ash on the properties of materials was studied and the mechanism of influence was analyzed. The test results show that performances of the samples were best when the ratio of red mud and fly ash is 5:4 and its flexural strength is 0.44MPa, compressive strength is 1.23MPa, density is 481kg/m3.
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Viana, Júlio C., and Lyudmil Todorov. "Structure-Properties Relationships in Processed Poly(ethylene terephthalate)." Key Engineering Materials 554-557 (June 2013): 1757–62. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1757.
Повний текст джерелаАнотація:
Abstract. Upon processing, polymeric products feature a complex microstructure. Besides evolving over the molded component, a through-the-thickness variation is also developed. This is the result of the thermo-mechanical environment (combined thermal and mechanical fields) applied during processing, which varies with the molding technique, the selected molding conditions and polymer properties (rheological, thermal, constitution). This complex microstructure makes rather intricate the establishment of structure-properties relationships in processed polymers. In fact, the basic identification of most relevant morphological parameters determining the behavior of the moldings is been revealed a difficult endeavor, further complicated by the multi-scale morphology presented by polymeric materials. This work follows an inductive approach for establishing the relationships between the structure and the properties (mechanical and barrier) of molded poly(ethylene terephthalate), PET. These relationships are investigated for specimens prepared by different methods, from “simple” to more “complex” stretching modes. Initially, PET specimens were prepared by stretching thin films at different high temperatures and strain rates, followed by quick cooling in a universal testing machine equipped with a thermal camera (uniaxial stretched specimens). More closely to processing, PET injection molded preforms were free blown without a mold with distinct conditions (free blown specimens). Finally, PET bottles were produced from the preforms also under different blown conditions. The morphology of all specimens was assessed by bi- and tri-refringence and DSC. The mechanical properties were evaluated by tensile tests at room temperature. Also, the oxygen transmission rate, OTR, was assessed for the PET bottles. For this low crystallinity and slowly crystallizable polymer, the initial modulus is mainly related to the amorphous phase (i.e., molecular mobility and orientation level). The yield stress appears to be determined by the degree of crystallinity and level of molecular orientation. In the case of free blown specimens (bi-axially stretched) the anisotropy of the initial modulus depends upon the induced anisotropy of the molecular orientation. OTR is influenced by the molecular orientation and the degree of crystallinity of the polymer. An attempt to interpret these types of relationships by molecular dynamics simulations is made.