Artículos de revistas: "Polyolefins stability"

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Kresge, E. N. "Polyolefin Thermoplastic Elastomer Blends". Rubber Chemistry and Technology 64, n.º 3 (1 de julio de 1991): 469–80. http://dx.doi.org/10.5254/1.3538564.

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Abstract Thermoplastic elastomers based on blends of polyolefins are an important family of engineering materials. Their importance arises from a combination of rubbery properties along with their thermoplastic nature in contrast to thermoset elastomers. The development of polyolefin thermoplastic elastomer blends follows somewhat that of thermoplastic elastomers based on block copolymers such as styrene-butadiene-styrene triblock copolymer and multisegmented polyurethane thermoplastic elastomers which were instrumental in showing the utility of thermoplastic processing methods. Polyoleflns are based on coordination catalysts that do not easily lend themselves to block or multisegmented copolymer synthesis. However, since polyolefins have many important attributes favorable to useful elastomeric systems, there was considerable incentive to produce thermoplastic elastomers based on simple α-olefins by some means. Low density, chemical stability, weather resistance, and ability to accept compounding ingredients without compromising physical properties are highly desirable. These considerations led to the development of polyolefin thermoplastic elastomer blends, and two types are now widely used: blends of ethylene-propylene rubber (EPM) with polypropylene (PP) and blends of EPDM and PP in which the rubber phase is highly crosslinked. This article reviews the nature of these blends. Both physical and Theological properties are very dependent on the morphology and crosslink density of the blend system. Moreover, the usefulness of practical systems depends extensively on compounding technology based on added plasticizers and fillers.

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2

Ishikawa, Masaru, Kiyotake Ushui y Kouichi Hatada. "Stability of plastic deformation in polyolefins". Polymer 37, n.º 9 (abril de 1996): 1601–5. http://dx.doi.org/10.1016/0032-3861(96)83708-6.

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3

Mammadli, Ulviyya M. "CROSSLINKED AND FILLED COMPOSITES BASED ON POLYOLEFINS". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, n.º 6 (6 de junio de 2018): 4. http://dx.doi.org/10.6060/tcct.20186106.5656.

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The paper gives an overview of literary material of a number of authors on the problem of the preparation of modified polyolefins during the crosslinking process. It is shown that materials based on polyolefins, characterized by increased heat-resistance favoring improvement of complex of technical requirements for light resistance, reliability, manufacturability in respect to the production and use of cable-conduction products. In particular, experimental data are presented on the use of organosilicon tin carboxylate in order to obtain products with the best quality characteristics. The results of theoretical and experimental investigations of the influence of formulation of polyolefin compositions on the kinetics of the crosslinking process and also on rheological and thermophysical properties are presented. The principal possibility of studying the influence of the irradiation dose on the regulation of the process of changing the structure of composites is considered.As shown by a number of authors, this method makes it possible to purposefully approach the development of crosslinked composite materials with predetermined properties. The method of radiation-chemical cross-linking compares the structure of the polymer base in the presence and without different types of fillers in highly filled composites. The data on the effect of radiation cross-linking conditions on the mesh density and the mechanical properties of cross-linked polyethylene at high temperatures are presented. The data on the chemical stability of cross-linked polyethylene to the action of various chemical reagents such as acetone, benzene, toluene, carbon tetrachloride, diethyl ether, benzene-76 and lubricants are given. One of the important circumstances in the study of the structure and properties of polymer composites is the possibility of mathematical modeling of viscoelastic compliance of thick-cross-linked polymers in correlation with the methodology of its theoretical parametric identification with subsequent prediction of the results of the thermomechanical experiment.Forcitation:Mammadli U.M. Crosslinked and filled composites based on polyolefins. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N6. P. 4-16

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4

Orji, Berlinda O. y Armando G. McDonald. "Evaluation of the Mechanical, Thermal and Rheological Properties of Recycled Polyolefins Rice-hull Composites". Materials 13, n.º 3 (3 de febrero de 2020): 667. http://dx.doi.org/10.3390/ma13030667.

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Understanding the properties and flow characteristics of recycled polyolefins in rice hull composite blends is of importance to facilitate process optimization whilst promoting sustainability. The influence of milled rice hull particle size (<0.5 mm and <1 mm) on properties of recycled polyolefins composites was studied with major focus on recycled high-density polyethylene (rHDPE) and polypropylene (rPP) together with added maleated polymer coupling agents. Composites were compounded/extruded using a twin-screw extruder and the thermal, mechanical, and physical properties were analyzed as well as their melt flow, dynamic. and capillary rheology tests. The incorporation of the <0.5 mm rice-hulls particles enhanced the composite properties of viscosity, flexural strength, moduli, water absorption, and thermal stability for both polyolefins with rHDPE composites showing more reliable properties as compared to rPP.

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Albano, C., J. González, M. Ichazo y D. Kaiser. "Thermal stability of blends of polyolefins and sisal fiber". Polymer Degradation and Stability 66, n.º 2 (noviembre de 1999): 179–90. http://dx.doi.org/10.1016/s0141-3910(99)00064-6.

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Kramer, E. y J. Koppelmann. "Measurement of oxidation stability of polyolefins by thermal analysis". Polymer Degradation and Stability 16, n.º 3 (enero de 1986): 261–75. http://dx.doi.org/10.1016/0141-3910(86)90030-3.

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Zaharescu, Traian, Ilona Plesa y Silviu Jipa. "Kinetic effects of silica nanoparticles on thermal and radiation stability of polyolefins". Polymer Bulletin 70, n.º 11 (14 de agosto de 2013): 2981–94. http://dx.doi.org/10.1007/s00289-013-1001-5.

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8

Mani, R., N. Sarkar, R. P. Singh y S. Sivaram. "Surface-Anchored Hindered-Amine Light Stabilizers for Improved UV Stability of Polyolefins". Journal of Macromolecular Science, Part A 33, n.º 9 (septiembre de 1996): 1217–26. http://dx.doi.org/10.1080/10601329608010916.

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9

Klimiec, Ewa, Halina Kaczmarek, Bogusław Królikowski y Grzegorz Kołaszczyński. "Cellular Polyolefin Composites as Piezoelectric Materials: Properties and Applications". Polymers 12, n.º 11 (16 de noviembre de 2020): 2698. http://dx.doi.org/10.3390/polym12112698.

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Piezoelectric polymers characterized by flexibility are sought for applications in microelectronics, medicine, telecommunications, and everyday devices. The objective of this work was to obtain piezoelectric polymeric composites with a cellular structure and to evaluate their usefulness in practice. Composites based on polyolefins (isotactic-polypropylene and polyethylene) with the addition of aluminosilicate fillers were manufactured by extrusion, and then polarized in a constant electric field at 100 V/µm. The content of mineral fillers up to 10 wt% in the polymer matrix enhances its electric stability and mechanical strength. The value of the piezoelectric coefficient d33 attained ~150 pC/N in the range of lower stresses and ~80 pC/N in the range of higher stresses, i.e., at ~120 kPa. The materials exhibited high durability in time, therefore, they can be used as transducers of mechanical energy of the human motion into electric energy. It was demonstrated that one shoe insert generates an energy of 1.1 mJ after a person walks for 300 s. The miniaturized integrated circuits based on polyolefin composites may be applied for the power supply of portable electronics. Due to their high sensitivity, they can be recommended for measuring the blood pulse.

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10

Lamas, L., G. A. Mendez, A. J. Müller y M. Pracella. "Thermal stability of blends of nylon 6 with polyolefins that contain acrylic acid". European Polymer Journal 34, n.º 12 (diciembre de 1998): 1865–70. http://dx.doi.org/10.1016/s0014-3057(98)00028-7.

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Kabir, Afsana S., Zhongshun Yuan, Takashi Kuboki y Chunbao (Charles) Xu. "De-polymerization of industrial lignins to improve the thermo-oxidative stability of polyolefins". Industrial Crops and Products 120 (septiembre de 2018): 238–49. http://dx.doi.org/10.1016/j.indcrop.2018.04.072.

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12

Paszkiewicz, Sandra, Krzysztof Pypeć, Izabela Irska y Elzbieta Piesowicz. "Functional Polymer Hybrid Nanocomposites Based on Polyolefins: A Review". Processes 8, n.º 11 (17 de noviembre de 2020): 1475. http://dx.doi.org/10.3390/pr8111475.

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For the last twenty years, polymer hybrid nanocomposites have enjoyed unflagging interest from numerous scientific groups and R&D departments, as they provide notable enhancement of properties, even at low nanofillers’ content. Their performance results from many factors, the most important of which is the uniform distribution in the entire volume of the matrix, that still is very challenging, but is the right choice of two types of nanoparticles that can lead to an increase of dispersion stability and even more uniform distribution of fillers. The incorporation of two types of nanofillers, especially when they differ in aspect ratio or chemical nature, allows to additively reduce the price of the final composite by replacing the more expensive filler with the cheaper one, or even synergistically improving the properties, e.g., mechanical, thermal, and barrier, etc., that can extend their usage in the industry. Despite numerous review papers on nanocomposites, there is no review on how the introduction of a hybrid system of nanofillers affects the properties of polyolefins, which are the most commonly used engineering plastics. This review deeply focuses on the structure–properties relationship of polyolefins-based hybrid nanocomposites, especially based on two types of polyethylenes (low-density polyethylenes (LDPE) and high-density polyethylenes (HDPE)) and polypropylene.

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13

Hollande, Louis, Sandra Domenek y Florent Allais. "Chemo-Enzymatic Synthesis of Renewable Sterically-Hindered Phenolic Antioxidants with Tunable Polarity from Lignocellulose and Vegetal Oil Components". International Journal of Molecular Sciences 19, n.º 11 (26 de octubre de 2018): 3358. http://dx.doi.org/10.3390/ijms19113358.

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Despite their great antioxidant activities, the use of natural phenols as antioxidant additives for polyolefins is limited owing to their weak thermal stability and hydrophilic character. Herein, we report a sustainable chemo-enzymatic synthesis of renewable lipophilic antioxidants specifically designed to overcome these restrictions using naturally occurring ferulic acid (found in lignocellulose) and vegetal oils (i.e., lauric, palmitic, stearic acids, and glycerol) as starting materials. A predictive Hansen and Hildebrand parameters-based approach was used to tailor the polarity of newly designed structures. A specific affinity of Candida antarctica lipase B (CAL-B) towards glycerol was demonstrated and exploited to efficiently synthesized the target compounds in yields ranging from 81 to 87%. Antiradical activity as well as radical scavenging behavior (H atom-donation, kinetics) of these new fully biobased additives were found superior to that of well-established, commercially available fossil-based antioxidants such as Irganox 1010® and Irganox 1076®. Finally, their greater thermal stabilities (302 < Td5% < 311 °C), established using thermal gravimetric analysis, combined with their high solubilities and antioxidant activities, make these novel sustainable phenolics a very attractive alternative to current fossil-based antioxidant additives in polyolefins.

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14

Raut, Iuliana, Mariana Calin, Zina Vuluga, Elvira Alexandrescu, Melania Liliana Arsene, Violeta Purcar, Cristian-Andi Nicolae, Ana Maria Gurban, Mihaela Doni y Luiza Jecu. "Comparative Study on the Behavior of Virgin and Recycled Polyolefins–Cellulose Composites in Natural Environmental Conditions". Journal of Composites Science 3, n.º 2 (15 de junio de 2019): 60. http://dx.doi.org/10.3390/jcs3020060.

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Polypropylene–cellulose composites have great potential in many important commercial applications, and it is important to understand and properly evaluate their biodegradative behavior to achieve improved composite formulations in accordance with their future applications. In the present study, an outdoor soil burial test was performed in order to evaluate the susceptibility to degradation of polyolefins–cellulose composites. The structural and morphological changes were analyzed by Fourier transform infra-red spectroscopy with attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). The weight loss of composite samples after burying in soil was recorded. The presence of new bands, as an indicator of degradation, was confirmed by FTIR-ATR spectra. The thermal stability of the composites after soil burial analyzed by TGA was slightly improved, with relatively higher temperatures being required to decompose the samples after exposure to environmental factors. SEM micrographs presented some modifications of the polymer surface, such as holes, cracks, exfoliations, and fractures. Increasing the cellulose percentage of the composite samples led to increased weight loss. From the obtained results, it can be concluded that composites based on polyolefins and renewable resources undergo a slow process of biodegradation after contact with environmental microorganisms and, with appropriate composition, could be applied to various environmental fields.

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15

Salas, Santiago D., Amanda L. T. Brandão, João B. P. Soares y José A. Romagnoli. "Data-Driven Estimation of Significant Kinetic Parameters Applied to the Synthesis of Polyolefins". Processes 7, n.º 5 (22 de mayo de 2019): 309. http://dx.doi.org/10.3390/pr7050309.

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A data-driven strategy for the online estimation of important kinetic parameters was assessed for the copolymerization of ethylene with 1,9-decadiene using a metallocene catalyst at different diene concentrations and reaction temperatures. An initial global sensitivity analysis selected the significant kinetic parameters of the system. The retrospective cost model refinement (RCMR) algorithm was adapted and implemented to estimate the significant kinetic parameters of the model in real time. After verifying stability and robustness, experimental data validated the algorithm performance. Results demonstrate the estimated kinetic parameters converge close to theoretical values without requiring prior knowledge of the polymerization model and the original kinetic values.

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16

Dolgov, V. V., Sh G. Sadykov, M. M. Usmanova, N. R. Ashurov y S. Sh Rashidova. "Polyethylene/Layered Aluminosilicate Nanocomposites: Investigation of Thermal Stability under Static and Dynamic Conditions". Eurasian Chemico-Technological Journal 18, n.º 4 (18 de febrero de 2017): 305. http://dx.doi.org/10.18321/ectj473.

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Based on linear low-density polyethylene and maleated polyethylene a polymer nanocomposites containing modified montmorillonite have been obtained, structure is investigated by XRD analysis. In turn, by the methods of thermal analysis in static and dynamic modes, the resistance of polymer nanocomposites to oxidative destruction it was investigated. In parallel with this, a comparative analysis of the thermal stability of polymer nanocomposites and polymer compositions containing commercially available organic antioxidants for stabilization of materials based on polyolefins. By results of the analysis carried out in a dynamic mode, for a series of polymer composites the activation energy of thermooxidative destruction was calculated. It is shown that the nanocomposites based on polyethylene, containing the modified montmorillonite not only not concede to polymer compositions with antioxidants in to thermal stability, but also exceed their. Accelerated tests, carried out at relatively high temperatures allowed evaluate the durability of polymer nanocomposites to thermooxidative destruction. Received results allow approve about a long-term thermal stability of these materials in the processing, and in the exploitation conditions.

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Missio, André L., Rafael A. Delucis, Caio Gomide Otoni, Pedro H. G. de Cademartori, Rodrigo Coldebella, Arthur B. Aramburu, Bruno D. Mattos et al. "Thermally Resistant, Self-Extinguishing Thermoplastic Composites Enabled by Tannin-Based Carbonaceous Particulate". Polymers 14, n.º 18 (7 de septiembre de 2022): 3743. http://dx.doi.org/10.3390/polym14183743.

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Flame-resistant materials are key components in buildings and several other engineering applications. In this study, flame retardancy and thermal stability were conferred to a highly flammable technical thermoplastic—polypropylene (PP)—upon compositing with a carbonaceous tannin-based particulate (CTP). Herein, we report on a straightforward, facile, and green approach to prepare self-extinguishing thermoplastic composites by thermoblending highly recalcitrant particulate. The thermal stability and mechanical properties of the composites are tethered to the CTP content. We demonstrate that the addition of up to 65 wt% of CTP improved the viscoelastic properties and hydrophobicity of the PP, whereas having marginal effects on bulk water interactions. Most importantly, compositing with CTP remarkably improved the thermal stability of the composites, especially over 300 °C, which is an important threshold associated with the combustion of volatiles. PP-CTP composites demonstrated great capacity to limit and stop fire propagation. Therefore, we offer an innovative route towards thermally resistant and self-extinguishing PP composites, which is enabled by sustainable tannin-based flame retardants capable of further broadening the technical range of commodity polyolefins to high temperature scenarios.

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Jozef, Rychlý, Rychlá Lyda, Novák Igor, Vanko Vladimír, Preťo Jozef, Janigová Ivica y Chodák Ivan. "Thermooxidative stability of hot melt adhesives based on metallocene polyolefins grafted with polar acrylic acid moieties". Polymer Testing 85 (mayo de 2020): 106422. http://dx.doi.org/10.1016/j.polymertesting.2020.106422.

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19

Zeynalov, Eldar B., Minira M. Agaguseynova y Nazila I. Salmanova. "EFFECT OF NANOCARBON ADDITIVES ON STABILITY OF POLYMER COMPOSITES". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, n.º 11 (27 de octubre de 2020): 4–12. http://dx.doi.org/10.6060/ivkkt.20206311.6213.

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This review briefly describes a state of research on the effect of fullerenes and carbon nanotubes (CNTs) on a durability of various polymer composite materials under extreme conditions. Fullerenes C60, C70, fullerene soot and CNTs integrated into the polymer matrix effectively prevent both thermal and thermo-oxidative degradation, as well as photo-oxidation processes. The stabilization mechanism of the carbon nanocompounds (CNC) is likewise and consists of the substantial end-capping termination of oxidation destructive chains on the nanocarbon skeleton. At that, the data array unequivocally indicates the predominant addition of carbon-centered alkyl radicals. Various polymer composite materials based on polyolefins, polyacrylates, polyamides, polycarbonates, elastomers are involved into the consideration. The approaches described are mostly aimed to increase the level of stabilizing activity of the polymer composites using different combinations of nanocarbon additives. The optimal dosage of CNC and interfacial compatibility between the polymer and fillers can significantly increase the heat resistance of the composites. The replacement of carbon atoms in the fullerene molecule with heteroatoms can also change its electronic properties and improve the antiradical and antioxidant activity. Areas for the effective use of fullerene C60 in aqueous media can be significantly expanded by modification with hydrophilic polymers. Thus, the performance of CNC integrated in the polymer composites is similar with those for strong synthetic stabilizers. CNC have good prospects for real industrial applications.

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Курбанов, М. А., И. С. Рамазанова, З. А. Дадашов, Ф. И. Мамедов, Г. Х. Гусейнова, У. В. Юсифова, Ф. Н. Татардар y И. А. Фараджзаде. "Релаксационные, термические и межфазные эффекты в композитах полимер-сегнетопьезокерамика различной структуры". Физика и техника полупроводников 53, n.º 8 (2019): 1115. http://dx.doi.org/10.21883/ftp.2019.08.48004.8970.

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AbstractThe relaxation and thermal processes and interphase phenomena in composites based on ferroelectrics and a polymer matrix are studied. It is shown that the charge stabilized at the interface of the composite during its electrothermopolarization is mainly determined by the structure of the polymer matrix and the piezoelectric phase. The results obtained make it possible to reveal the main factors affecting the piezoelectric properties of the heterogeneous polymer–ferroelectric ceramic system. Polyolefins and fluorine-containing polar polymers are used as the organic phase, and ferroelectric ceramics of rhombohedral, tetragonal, and mixed structures serve as the inorganic phase. The relaxation processes and interphase phenomena are studied using a differential scanning calorimeter, and the charge state is analyzed by recording the thermally stimulated depolarization current. The charge-state stability is determined by the electret potential difference of the composites. The molecular relaxation is analyzed by the dielectric method. It is established that the composites in which the interphase interaction is more pronounced are characterized by high piezoelectric properties.

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Maldhure, Atul V. y Jayant D. Ekhe. "Effect of modifications of lignin on thermal, structural, and mechanical properties of polypropylene/modified lignin blends". Journal of Thermoplastic Composite Materials 30, n.º 5 (22 de octubre de 2015): 625–45. http://dx.doi.org/10.1177/0892705715610402.

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Use of organic biomass, industrial waste lignin, was considered interesting due to its easy availability, polymeric nature, and ample scope to modify with an aim to replace conventional metal oxides to achieve improved properties of the blend when blended with polyolefins. To study the effect of chemical modification of lignin on the thermal, structural, and mechanical properties of polypropylene (PP)/modified lignin blends, purified industrial waste lignin was modified by two different chemical methods and blended in various proportions in PP matrix. The thermal stability of the blends was studied by thermogravimetric analysis, whereas melting and crystallization behavior of blends was studied by non-isothermal differential scanning calorimetry. The results show improved thermal stability of blends with increasing modified lignin proportion in the PP matrix. More depression in melting point was observed in PP/alkylated lignin blends than PP/arylated lignin blends, whereas addition of alkylated lignin shows polymorphism in PP matrix. Intermolecular interactions between blend components have been evaluated by applying several mathematical models to experimental mechanical property data. In most of the cases, good agreement has been obtained between the predictions made by using mathematical models and interpretations done on the basis of experimental data, showing the suitability of these models for predicting the mechanical properties of PP/modified lignin blends.

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Georgieva, Krasimira, Yordan Denev y Nikola Todorov. "Characterization of multilayer films based on recycled high density polyethylene (hdpe) using methods of ir-spectroscopy". International Conference on Technics, Technologies and Education, n.º 1 (2018): 6–11. http://dx.doi.org/10.15547/ictte.2018.01.001.

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The spectra in middle IR-region of common polymers obtain different characteristic bands which can be analyzed for proper characterization and identification of single polymers in polymer mixture. In the present work the results of multilayer polymer films based on recycled high density polyethylene (HDPE) characterization are presented. The main technological problem in the secondary processing of HDPE is determination of the polymer degradation degree. The most suitable region in the IR-region is between 1850 – 1630 cm-1 , where the carbonyl group displays bands related to the oxidation processes of polyolefins. All IR-spectra have weak absorption in this region which proves the oxidation processes in macromolecular chains. The carbonyl index of the studied films is calculated too. It is proved that the recycling process of HDPE is insignificantly related to its stability, macromolecular characteristics and possibility for secondary processing. The results of present study show a perspective possibility for utilization of huge amounts of waste HDPE as main component in multilayer films with good characteristics, suitable for packaging purposes of foods.

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Quiles-Carrillo, Luis, Sergi Montava-Jordà, Teodomiro Boronat, Chris Sammon, Rafael Balart y Sergio Torres-Giner. "On the Use of Gallic Acid as a Potential Natural Antioxidant and Ultraviolet Light Stabilizer in Cast-Extruded Bio-Based High-Density Polyethylene Films". Polymers 12, n.º 1 (23 de diciembre de 2019): 31. http://dx.doi.org/10.3390/polym12010031.

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This study originally explores the use of gallic acid (GA) as a natural additive in bio-based high-density polyethylene (bio-HDPE) formulations. Thus, bio-HDPE was first melt-compounded with two different loadings of GA, namely 0.3 and 0.8 parts per hundred resin (phr) of biopolymer, by twin-screw extrusion and thereafter shaped into films using a cast-roll machine. The resultant bio-HDPE films containing GA were characterized in terms of their mechanical, morphological, and thermal performance as well as ultraviolet (UV) light stability to evaluate their potential application in food packaging. The incorporation of 0.3 and 0.8 phr of GA reduced the mechanical ductility and crystallinity of bio-HDPE, but it positively contributed to delaying the onset oxidation temperature (OOT) by 36.5 °C and nearly 44 °C, respectively. Moreover, the oxidation induction time (OIT) of bio-HDPE, measured at 210 °C, was delayed for up to approximately 56 and 240 min, respectively. Furthermore, the UV light stability of the bio-HDPE films was remarkably improved, remaining stable for an exposure time of 10 h even at the lowest GA content. The addition of the natural antioxidant slightly induced a yellow color in the bio-HDPE films and it also reduced their transparency, although a high contact transparency level was maintained. This property can be desirable in some packaging materials for light protection, especially UV radiation, which causes lipid oxidation in food products. Therefore, GA can successfully improve the thermal resistance and UV light stability of green polyolefins and will potentially promote the use of natural additives for sustainable food packaging applications.

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Kamarudin, Siti Hasnah, Emiliana Rose Jusoh, Luqman Chuah Abdullah, Mohd Halim Shah Ismail, Min Min Aung y Chantara Thevy Ratnam. "Thermal and Dynamics Mechanical Analysis of Polypropylene Blown Films with Crude Palm Oil as Plasticizer". Indonesian Journal of Chemistry 19, n.º 3 (29 de mayo de 2019): 545. http://dx.doi.org/10.22146/ijc.30460.

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This research aims to investigate the effect of crude palm oil (CPO) as a plasticizer in polypropylene blown film on thermal and dynamic mechanical properties. Polypropylene (PP) was blended with 1, 3, and 5% of CPO using a twin screw extruder. The extruded samples were blown using the blown thin film technique. The samples were analyzed using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). From the dynamic mechanical analysis, the storage modulus and loss modulus for PP presented decreasing pattern about 3–5% due to the action of CPO as plasticizer which introduced free volume and enabled the polyolefins chains to deform more easily. The glass transition temperatures (Tg) of PP were found being shifted to lower temperature from 10 to 1 °C with the increasing CPO content. The fraction of crystallization was determined using DSC. The thermogravimetric analysis (TGA) results showed that the incorporation of CPO as plasticizer showed a small increased effect in the thermal stability for PP. These findings have contributed new knowledge to the additives area and give important implications for designing and manufacturing polymer packaging materials.

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Rigail-Cedeño, Andrés, Miriam Lazo, Julio Gaona, Joshua Delgado, Clotario V. Tapia-Bastidas, Ana L. Rivas, Estephany Adrián y Rodrigo Perugachi. "Processability and Physical Properties of Compatibilized Recycled HDPE/Rice Husk Biocomposites". Journal of Manufacturing and Materials Processing 6, n.º 4 (23 de junio de 2022): 67. http://dx.doi.org/10.3390/jmmp6040067.

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The circular economy promotes plastic recycling, waste minimization, and sustainable materials. Hence, the use of agricultural waste and recycled plastics is an eco-friendly and economic outlook for developing eco-designed products. Moreover, new alternatives to reinforce recycled polyolefins and add value to agroindustrial byproducts are emerging to develop processable materials with reliable performance for industrial applications. In this study, post-consumer recycled high-density polyethylene (rHDPE) and ground rice husk (RH) of 20% w/w were blended in a torque rheometer with or without the following coupling agents: (i) maleic anhydride grafted polymer (MAEO) 5% w/w, (ii) neoalkoxy titanate (NAT) 1.5% w/w, and (iii) ethylene–glycidyl methacrylate copolymer (EGMA) 5% w/w. In terms of processability, the addition of RH decreased the specific energy consumption in the torque experiments with or without additives compared to neat rHDPE. Furthermore, the time to reach thermal stability in the extrusion process was improved with EGMA and MAEO compatibilizers. Tensile and impact test results showed that using coupling agents enhanced the properties of the RH composites. On the other hand, thermal properties analyzed through differential scanning calorimetry and thermogravimetric analysis showed no significant variation for all composites. The morphology of the tensile fracture surfaces was observed via scanning electron microscopy. The results show that these recycled composites are feasible for manufacturing products when an appropriate compatibilizer is used.

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Liu, Guangtian. "Cationic vinyl monomer-grafted polypropylene preparation and its use as a compatibilizer for polypropylene/poly(vinyl chloride) blends". Journal of Polymer Engineering 35, n.º 3 (1 de abril de 2015): 223–29. http://dx.doi.org/10.1515/polyeng-2014-0098.

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Abstract Grafting polymerization is a valuable method for the modification of the chemical and physical properties of polymer surfaces. In this paper, the grafting of cationic vinyl monomer with quaternary ammonium groups, i.e., methacryloxyethyltrimethyl ammonium chloride (DMC), onto the isotactic polypropylene (iPP) granule was performed by the suspension solid-state grafting process. The technique offers new opportunities in modification of polyolefins, which has advantages of being solventless and having a lower process temperature. The grafted PP [PP-g-(St-co-DMC)] was systematically characterized by using various analytic tools including Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The FTIR spectra of the grafted iPP confirmed that DMC was successfully grafted onto the iPP backbone. The results of TGA and the hydrophilicity measurement indicated that the thermal stability of the grafted iPP was enhanced remarkably, and the hydrophilicity was also enhanced due to the addition of hydrophilic quaternary ammonium groups. Furthermore, the mechanical properties effect of PP-g-(St-co-DMC) on PP/poly(vinyl chloride) (PVC) blends was investigated. The measurements of tensile strength and impact strength indicated that the PP-g-(St-co-DMC) could remarkably enhance compatibility of PP/PVC blends. The tensile strength and the impact strength of PP/PVC blends with a concentration of PP-g-(St-co-DMC) at 4% (wt) increased up to 19.15% and 74.48%, respectively.

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Chernyavsky, A. y A. Grigorov. "SHIPPING FUEL PRODUCED FROM SECONDARY POLYMER RAW MATERIALS". Integrated Technologies and Energy Saving, n.º 4 (12 de diciembre de 2022): 39–45. http://dx.doi.org/10.20998/2078-5364.2022.4.04.

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The article considers the possibility of expanding the raw material base of the production of motor fuels, particularly the fuels for shipping due to the use of secondary polymer raw materials. It was established that this raw material, which is represented by various polyolefins, is characterized by the absence or rather low (up to 150–200 ppm) content of sulfur-containing compounds. Therefore, according to such an indicator as the sulfur content, using thermal or catalytic pyrolysis technologies in a reactor-type apparatus, it is possible to obtain fuels from secondary polymer raw materials, which in terms of sulfur content (0.5 % and 0.1 %, respectively) will correspond to marine gasoil (MGO) or low sulfur marine gasoil (LS-MGO). It was experimentally established that the products of thermal pyrolysis of secondary polymer raw materials contain up to 30–40 % of olefinic hydrocarbons, which have low chemical stability and increased hygroscopicity compared to paraffinic and naphthenic hydrocarbons. Given their properties, such products should only be used as components of marine fuels. The products of catalytic pyrolysis (the process was carried out using the ZSM-5 zeolite catalyst) of secondary polymer raw materials, on the contrary, have high chemical stability due to the low (up to 3 %) content of olefinic hydrocarbons. But, at the same time, they contain up to 15 % aromatic hydrocarbons in their composition, which does not exceed the generally accepted restrictions on their content in motor fuels. It has been determined that the initial boiling point of the obtained fractions is the main parameter, which can be used to regulate some quality indicators of the products obtained. Its increase significantly reduces hygroscopicity and increases the flash point of the obtained products. However, it is not advisable to significantly increase this indicator, given the decrease in the yield of the target product (increasing the boiling point of the fraction by only 1 °C leads to a decrease in its yield by 0.275–0.325 %).

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Kahraman, Merve y Nilgün Kızılcan. "Investigation of flame retardancy properties of polypropylene-colemanite and intumescent flame retardant additive blends". Synthesis and Sintering 2, n.º 3 (10 de septiembre de 2022): 110–19. http://dx.doi.org/10.53063/synsint.2022.2397.

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Polypropylene (PP) represents a considerable proportion of polyolefins (PO) used in different industrial applications such as automobile components, textiles, packaging, insulation, medical devices, various housewares and household appliances due to its efficient cost, desirable mechanical, thermal and electrical properties, easy processability and recyclability. Because of its carbonaceous structure, PP is a highly flammable material with a LOI value of 18 that presents serious fire hazard. In this research, Intumescent flame retardant (IFR) and colemanite were added to polypropylene to compose 30% of the total mass of the polymeric compounds and the synergistic effect of colemanite with intumescent flame retardant (IFR) additive in PP was investigated by limiting oxygen index (LOI), glow wire test (GWT), UL-94 test and mechanical properties measurements. The LOI, UL 94 and glow wire test results showed that colemanite had a significant effect on flame retardancy and LOI value which can reach to 37.6 % with loading level of 2 wt.% colemanite at the total amount of flame retardant additives kept constant at 30 wt.%. Additionally, the PP/IFR compounds passed UL 94 V0 rating and both 750 °C and 850 °C glow wire tests and with 2-8 wt.% colemanite loading. According to TGA analyses, the results indicated that colemanite improved the thermal stability of PP/IFR compounds and also promoted the formation of char layer. When colemanite mineral added to polypropylene without IFR system, it has no effect on flame retardancy properties of polypropylene. When all properties have been taken into consideration, colemanite can be used up to 6 wt% in IFR.

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29

Chin, Alfred, Radha R. Ramakrishnan, Norman N. Yoshimura, Erwin W. S. Jeong, Leslie J. Nii y Lourdes S. DiMeglio. "Paclitaxel Stability and Compatibility in Polyolefin Containers". Annals of Pharmacotherapy 28, n.º 1 (enero de 1994): 35–36. http://dx.doi.org/10.1177/106002809402800105.

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OBJECTIVE: To determine the compatibility and stability of paclitaxel in polyolefin containers. DESIGN: The following paclitaxel concentrations were determined by a stability-indicating HPLC method: 0.3 and 1.2 mg/mL diluted in dextrose 5% for injection, USP (D5W) or sodium chloride 0.9% for injection, USP (NS). The solutions were prepared in polyolefin containers and the stability and compatibility were monitored for 48 hours when stored at ambient temperature (20–23 °C)and normal fluorescent lighting. A mixture of the drug carrier consisting of approximately 10% polyoxyethylated castor oil (Cremophor EL) and 10% ethanol in D5W and NS, without paclitaxel, was studied to differentiate the effect of paclitaxel from the effect of the drug carrier on the container. Paclitaxel concentrations, pH changes, and visual clarity were used as stability and compatibility indicators. RESULTS: Paclitaxel concentrations remained at 96–99 percent of the initial concentration for up to 48 hours when placed in the polyolefin containers. No changes in color or visual clarity were noted. Only minor changes in the pH of the admixtures were observed. CONCLUSIONS: Paclitaxel diluted in D5W or NS at concentrations of 0.3 and 1.2 mg/mL is stable and compatible in flexible, polyolefin containers for up to 48 hours.

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30

Bayandin, V. V., N. S. Shaglaeva, T. A. Podgorbunskaya, N. D. Lukyanov, N. V. Minaev y С. С. Makarov. "IR spectroscopy and X-ray diffraction analysis of industrial polyvinyl chloride suspension". Proceedings of Universities. Applied Chemistry and Biotechnology 10, n.º 3 (8 de octubre de 2020): 529–35. http://dx.doi.org/10.21285/2227-2925-2020-10-3-529-535.

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In terms of the contemporary plastic industry, world production of polyvinyl chloride is second only to polyolefins. Recyclable by almost all known methods, polyvinyl chloride offers high strength, good insulating properties, as well as resistance to acids, oxidising agents and solvents. At the same time, the ability to process polyvinyl chloride into products is limited by its lack of stability at high melt viscosity temperatures, since hydrogen chloride released during its heating catalyses further process of polymer decomposition. Thus, due to the softening temperature of polyvinyl chloride being higher than its decomposition temperature, it cannot be processed in its pure form. Consequently, functional polyvinyl chloride-based materials tend to be composites. By varying the composition of mixtures, plastic masses characterised by either very soft (plastic compounds) or hard (vinyl plastics) structures can be obtained. The properties of polyvinyl chloride-based polymer products are largely determined by the structure and morphology of the polymer. In the present work, the properties of industrial suspension polyvinyl chloride (Sayanskkhimplast JSC, Irkutsk Oblast) were studied in detail for the first time. The molecular weight of the polymer determined by the viscometric method was 1.0 · 106. Thermogravimetric analysis showed that polyvinyl chloride mass loss started to occur at 160 °C. Following the complete IR band assignment of the polymer, the polyvinyl chloride under study was established to contain no foreign substances (impurities of stabilisers, emulsifiers and additives). The diffraction curve of the polymer was established to be qualitatively similar to equivalent partially crystalline polymers. Two amorphous halos were detected at 2θ of 24° 30′ and 39° 30′ below a group of crystalline peaks. The crystallinity degree of polyvinyl chloride was determined and mechanisms for the formation of its regular and irregular structure were proposed.

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Biale, Greta, Jacopo La Nasa, Marco Mattonai, Andrea Corti, Virginia Vinciguerra, Valter Castelvetro y Francesca Modugno. "A Systematic Study on the Degradation Products Generated from Artificially Aged Microplastics". Polymers 13, n.º 12 (18 de junio de 2021): 1997. http://dx.doi.org/10.3390/polym13121997.

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Most of the analytical studies focused on microplastics (MPs) are based on the detection and identification of the polymers constituting the particles. On the other hand, plastic debris in the environment undergoes chemical and physical degradation processes leading not only to mechanical but also to molecular fragmentation quickly resulting in the formation of leachable, soluble and/or volatile degradation products that are released in the environment. We performed the analysis of reference MPs–polymer micropowders obtained by grinding a set of five polymer types down to final size in the 857–509 μm range, namely high- and low-density polyethylene, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (PET). The reference MPs were artificially aged in a solar-box to investigate their degradation processes by characterizing the aged (photo-oxidized) MPs and their low molecular weight and/or highly oxidized fraction. For this purpose, the artificially aged MPs were subjected to extraction in polar organic solvents, targeting selective recovery of the low molecular weight fractions generated during the artificial aging. Analysis of the extractable fractions and of the residues was carried out by a multi-technique approach combining evolved gas analysis–mass spectrometry (EGA–MS), pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS), and size exclusion chromatography (SEC). The results provided information on the degradation products formed during accelerated aging. Up to 18 wt% of extractable, low molecular weight fraction was recovered from the photo-aged MPs, depending on the polymer type. The photo-degradation products of polyolefins (PE and PP) included a wide range of long chain alcohols, aldehydes, ketones, carboxylic acids, and hydroxy acids, as detected in the soluble fractions of aged samples. SEC analyses also showed a marked decrease in the average molecular weight of PP polymer chains, whereas cross-linking was observed in the case of PS. The most abundant low molecular weight photo-degradation products of PS were benzoic acid and 1,4-benzenedicarboxylic acid, while PET had the highest stability towards aging, as indicated by the modest generation of low molecular weight species.

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32

Yin, Hua y Yao Ting Zhu. "Experimental Study of Asphalt Mixtures Containing Polyolefin/Ethylene Copolymer Modifier by Dry Process". Advanced Materials Research 671-674 (marzo de 2013): 1945–49. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1945.

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This paper presents a laboratory test to characterize the pavement performance of asphalt mixture containing polyolefin/ethylene copolymer modifier. The modifier is directly added into mixture like aggregates and is not necessary to modify the asphalt binder firstly, which is different with conventional modifier and is so-called dry process. Based on the aggregate grade of AC-13 mixture, the mechanical properties of polyolefin/ethylene copolymer modified hot mixtures asphalt (dry process) were studied by experimental tests, which include the high-temperature stability and water stability. The test results indicate that compared to the SBS asphalt mixture the dynamic stability and TSR improved 66% and 2.3% respectively, when the addition of RK300 is 0.3%.

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33

Malavolta, Laura, Antonio Terella, Francesca De Giorgio y Catia Arbizzani. "Improved Adhesion of Nafion™-Coated Separator to Water-Processable LiNi0.5Mn1.5O4 Electrodes". Batteries 6, n.º 2 (11 de mayo de 2020): 28. http://dx.doi.org/10.3390/batteries6020028.

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The adhesion between electrode and separator is a key feature in cell assembly. Nafion™-coated separators for water-processed LiNi0.5Mn1.5O4 (LNMO) electrodes are here proposed as an alternative to the polyolefin separators. Specifically, polyolefin separators are modified with Nafion™ solutions and their adhesion to high-potential LNMO electrodes is investigated. The physicochemical properties of the Nafion™-coated separator and its electrochemical performance in Li/LNMO cells are discussed and compared to those obtained with polyolefin Celgard® (Charlotte, NC, USA) PP2075 separator. Improved adhesion and cycling stability, which could be further enhanced by a mild lamination process, were demonstrated with a thin layer of Nafion™ (0.1 mg cm−2).

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34

Lee, Jun H., Barry R. Goldspiel, Sujung Ryu y Gopal K. Potti. "Stability of tacrolimus solutions in polyolefin containers". American Journal of Health-System Pharmacy 73, n.º 3 (1 de febrero de 2016): 137–42. http://dx.doi.org/10.2146/ajhp150264.

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35

Grigoryeva, Olga, Olga Starostenko, Alexander Fainleib, Gonzalo Martínez-Barrera, Jean-Marc Saiter y Boulos Youssef. "Joint Reuse of Post-consumer Polyolefines and Ground Tire Rubber for Thermoplastic Elastomers Production. Mechanical Performance, Thermal and Radiation Stability". Chemistry & Chemical Technology 6, n.º 1 (15 de marzo de 2012): 59–72. http://dx.doi.org/10.23939/chcht06.01.059.

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36

Dai, Jianhui, Chuan Shi, Chao Li, Xiu Shen, Longqing Peng, Dezhi Wu, Daoheng Sun, Peng Zhang y Jinbao Zhao. "A rational design of separator with substantially enhanced thermal features for lithium-ion batteries by the polydopamine–ceramic composite modification of polyolefin membranes". Energy & Environmental Science 9, n.º 10 (2016): 3252–61. http://dx.doi.org/10.1039/c6ee01219a.

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We report a rational design of separator for lithium-ion batteries by the polydopamine–ceramic composite-modification of polyolefin membranes, which leads to substantially enhanced thermal and mechanical stability.

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37

Wear, Jennifer, Timothy B. McPherson y William M. Kolling. "Stability of sodium bicarbonate solutions in polyolefin bags". American Journal of Health-System Pharmacy 67, n.º 12 (15 de junio de 2010): 1026–29. http://dx.doi.org/10.2146/ajhp090301.

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38

Alberti, M. G., A. Enfedaque, J. C. Gálvez y A. Picazo. "Recent advances in structural fibre-reinforced concrete focused on polyolefin-based macro-synthetic fibres". Materiales de Construcción 70, n.º 337 (18 de febrero de 2020): 206. http://dx.doi.org/10.3989/mc.2020.12418.

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Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.

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39

Almagambetova, Elise, David Hutchinson, Danielle M. Blais y Fang Zhao. "Stability of Diluted Adenosine Solutions in Polyolefin Infusion Bags". Hospital Pharmacy 48, n.º 6 (junio de 2013): 484–88. http://dx.doi.org/10.1310/hpj4806-484.

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40

Szpilska, Katarzyna, Krystyna Czaja y Stanislaw Kudla. "Thermal stability and flammability of polyolefin/halloysite nanotubes composites". Polimery 61, n.º 11/12 (noviembre de 2015): 673–79. http://dx.doi.org/10.14314/polimery.2015.673.

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41

Sayre, Brian E., Terrence Prettyman y Gagan Kaushal. "Extended Stability of Magnesium Sulfate Infusions Prepared in Polyolefin Bags". Hospital Pharmacy 47, n.º 4 (abril de 2012): 289–92. http://dx.doi.org/10.1310/hpj4704-289.

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42

Sayre, Brian E., Terrence Prettyman y Gagan Kaushal. "Extended Stability of Sodium Bicarbonate Infusions Prepared in Polyolefin Bags". Hospital Pharmacy 47, n.º 7 (julio de 2012): 538–43. http://dx.doi.org/10.1310/hpj4707-538.

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43

Dolatkhani, Marc, Henri Cramail, Alain Deffieux, Maria Rosário Ribeiro, Jorge M. Santos y João M. Bordado. "Synthesis of polyolefin based materials with improved thermo-oxidative stability". Macromolecular Symposia 213, n.º 1 (junio de 2004): 347–56. http://dx.doi.org/10.1002/masy.200450931.

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44

Anžlovar, Alojz, Mateja Primožič, Iztok Švab, Maja Leitgeb, Željko Knez y Ema Žagar. "Polyolefin/ZnO Composites Prepared by Melt Processing". Molecules 24, n.º 13 (2 de julio de 2019): 2432. http://dx.doi.org/10.3390/molecules24132432.

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Composites of polyolefin matrices (HDPE and PP) were prepared by melt processing using two commercially available nano ZnO powders (Zinkoxyd aktiv and Zano 20). The mechanical and thermal properties, UV-Vis stability, and antibacterial activity of composites were studied. Tensile testing revealed that both nano ZnO types have no particular effect on the mechanical properties of HDPE composites, while some positive trends are observed for the PP-based composites, but only when Zano 20 was used as a nanofiller. Minimal changes in mechanical properties of composites are supported by an almost unaffected degree of crystallinity of polymer matrix. All polyolefin/ZnO composites exposed to artificial sunlight for 8–10 weeks show more pronounced color change than pure matrices. This effect is more evident for the HDPE than for the PP based composites. Color change also depends on the ZnO concentration and type; composites with Zano 20 show more intense color changes than those prepared with Zinkoxyd aktiv. Results of the antibacterial properties study show very high activity of polyolefin/ZnO composites against Staphylococcus aureus regardless of the ZnO surface modification, while antibacterial activity against Escherichia coli shows only the composites prepared with unmodified ZnO. This phenomenon is explained by different membrane structure of gram-positive (S. aureus) and gram-negative (E. coli) bacteria.

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45

Lin, Guo, Chenchen Liu, Zhongxiang Bai, Shuning Liu, Mangui Han, Yumin Huang y Xiaobo Liu. "Heat-resistant poly (arylene ether nitriles) separator for high-safety lithium batteries via dual-functional modification". Journal of Physics: Conference Series 2338, n.º 1 (1 de septiembre de 2022): 012031. http://dx.doi.org/10.1088/1742-6596/2338/1/012031.

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Abstract Herein, we report a dual-modified organic-inorganic separator as an alternative to polyolefin commercial separator for lithium metal batteries. This composite separator exhibits high thermal stability properties due to the use of an engineering plastic matrix of poly (arylene ether nitriles) (PEN). The dual hydrophilic modification strategy also allows the separator to have a high ionic conductivity and a low interfacial impedance. With this new separator, lithium-metal batteries have high charge/discharge capacity and high-rate performance. Moreover, Li/Li symmetric cells display long-term stability and phenomenon of suppressing the lithium dendrite in lithium-metal batteries.

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46

Sundaramurthi, Prakash, Sean Chadwick y Chakravarthy Narasimhan. "Physicochemical stability of pembrolizumab admixture solution in normal saline intravenous infusion bag". Journal of Oncology Pharmacy Practice 26, n.º 3 (25 de agosto de 2019): 641–46. http://dx.doi.org/10.1177/1078155219868516.

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Introduction Pembrolizumab is an anti-PD-1 monoclonal antibody, approved and under development for numerous indications in oncology. It is available as either lyophilized powder for reconstitution or ready-to-use solution. Both are required to be diluted in saline or dextrose solution prior to intravenous infusion. After dilution, the recommendation per summary of product characteristics is 24 h at 2–8℃ and 6 h at room temperature. The purpose of this study was to investigate the physicochemical stability of pembrolizumab diluted solution (1 mg/mL) at both refrigerated and room temperature conditions for an extended period. Methods Under aseptic conditions, pembrolizumab was diluted in 250 mL of saline injection in polyolefin bags to obtain the final protein concentration of 1 mg/mL. Thus, prepared bags were then stored at either 5℃ ± 3℃, refrigerator exposing the product to ambient light or room temperature (20℃ ± 3℃) on the benchtop. Results Using several analytical methods, it was demonstrated that pembrolizumab solution for infusion, diluted in normal saline can be stored in polyolefin infusion bags for at least 1 week at 5℃ or RT with no evidence of chemical or physical instability. No aggregation was observed. Conclusion Thus, the practical use of aseptically prepared diluted pembrolizumab in saline can be safely extended to optimize the workload of centralized preparation units and to minimize costs. However, it is the responsibility of the end-user to maintain overall quality of prepared admixture solution that is administered to patient, by following aseptic compounding process as recommended in the packaging insert.

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47

Chen, Weiping, Xiang Wang, Jianyu Liang, Yao Chen, Wei Ma y Siyuan Zhang. "A High Performance Polyacrylonitrile Composite Separator with Cellulose Acetate and Nano-Hydroxyapatite for Lithium-Ion Batteries". Membranes 12, n.º 2 (20 de enero de 2022): 124. http://dx.doi.org/10.3390/membranes12020124.

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The traditional commercial polyolefin separators suffer from high-temperature thermal shrinkage, low electrolyte wettability and other issues. In order to improve the overall performance of the separators, electrostatic spinning technology was applied to obtain PAN nanofiber separators with an average diameter of 320 nm. Then cellulose acetate (CA) resin and nano-hydroxyapatite (HAP) were introduced to fabricate the PAN/CA/HAP composite separators through the constant temperature hot pressing and dip-coating crafts. The composite separator has a good thermal stability, with no significant dimensional change after a constant temperature treatment of 200 °C for 35 min. The electrolyte uptake rate of the PAN/CA/HAP-1.0 composite separator reaches 281%, which exhibits an efficient ionic conductivity. At the same time, it also attains a tensile strength of 11.18 MPa, which meets the requirement for separator use. Button cells assembled from PAN/CA/HAP-1.0 composite separators have an excellent rate of performance (160.42 mAh·g−1 at 0.2 C) and cycle capability (157.6 mAh·g−1 after 50 cycles at 0.5 C). The results support that lithium-ion batteries assembled with PAN/CA/HAP-1.0 composite separators will exhibit higher safety stability and better electrochemical performance than that of polyolefin separators, with a very immense potential for application.

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48

Mun, Sung Cik y Jong Ho Won. "Manufacturing Processes of Microporous Polyolefin Separators for Lithium-Ion Batteries and Correlations between Mechanical and Physical Properties". Crystals 11, n.º 9 (24 de agosto de 2021): 1013. http://dx.doi.org/10.3390/cryst11091013.

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Rechargeable lithium-ion batteries (LIBs) have emerged as a key technology to meet the demand for electric vehicles, energy storage systems, and portable electronics. In LIBs, a permeable porous membrane (separator) is an essential component located between positive and negative electrodes to prevent physical contact between the two electrodes and transfer lithium ions. Among several types, microporous polyolefin membranes have dominated the commercial separator market for LIBs operated with liquid electrolytes, favored for their chemical and electrochemical stability, high mechanical strength, uniform pore size, and inexpensive manufacturing and materials cost. In this review, we summarize the principles and theoretical background underlying conventional manufacturing processes and newly emerging microporous polyolefin separators. Based on their mechanical and physical properties, as collected from the literature, we introduce a number of processing type-dependent characteristics and universal correlations among their properties. This will provide a macroscopic view on the subject and a guideline for the development of next-generation separators.

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DeAngelis, Michael, Alexander Ferrara, Kaleigh Gregory, Kimberly Zammit y Fang Zhao. "Stability of 2 mg/mL Adenosine Solution in Polyvinyl Chloride and Polyolefin Infusion Bags". Hospital Pharmacy 53, n.º 2 (30 de noviembre de 2017): 73–74. http://dx.doi.org/10.1177/0018578717742516.

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Adenosine is a potent endogenous mediator of vasodilation. Compounded sterile solutions of adenosine are used in cardiac catheterization lab to perform stress tests on the heart. These tests are used to determine the fractional flow reserve (FFR) and are commonly used in the management and diagnosis of cardiovascular conditions. The purpose of this study was to assess the physical and chemical stability of 2 mg/mL adenosine in 0.9% Sodium Chloride Injection, USP in polyvinyl chloride [PVC]) and polyolefin infusion bags stored at room temperature (20°C-25°C) and under refrigeration (2°C-8°C). The compounding and analytical methods used in this study were very similar to those described in the prior publications from the authors’ laboratory. To ensure a uniform starting concentration of all stability samples, a batch of 2 mg/mL adenosine solution was prepared and then packaged into empty PVC and polyolefin infusion bags. These stability samples were prepared in triplicate for each bag type and storage temperature (a total of 12 samples). The infusion bag samples were assessed for stability immediately after preparation and after 1 day, 3 days, 7 days, and 14 days. At each time point, the infusion bags were first visually inspected against a light background for color change, clarity, and particulates. Aliquots were drawn from each sample at each time point for pH analysis and high-performance liquid chromatography (HPLC) analysis. Over 14 days of storage at room temperature or refrigeration, no considerable change in visual appearance or pH was observed in any bags. All samples retained 90% to 110% of the initial drug concentration. No significant degradation peaks were observed in the HPLC chromatograms.

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50

Frenette, Anne Julie, Robert D. MacLean, David Williamson, Pierre Marsolais y Ronald F. Donnelly. "Stability of levothyroxine injection in glass, polyvinyl chloride, and polyolefin containers". American Journal of Health-System Pharmacy 68, n.º 18 (15 de septiembre de 2011): 1723–28. http://dx.doi.org/10.2146/ajhp100599.

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