Добірка наукової літератури з теми "Polymer-rubber compositions"

The study results of the influence of butadiene-nitrile rubber different grades concentration, cross-linking agent type and content on the physico-mechanical and thermo-deformation properties of polymer compositions based on polypropylene are presented. Mixing of the components was carried out on hot rollers in the melt mode at 170 °C. A preliminary study of rubber concentration affect on the properties of compositions based on polypropylene showed that the introduction of an elastomeric component leads to a regular decrease in the strength and elongation at break of the compositions. The results of investigation of the thermo-deformation properties of polymer compositions showed that at a rubber concentration of 30wt%, and higher on thermomechanical curves, the region of the high-elastic state characteristic of rubbers is noticeably distinguished. Taking into account that the rubber materials are obtained during the process of their vulcanization, it seemed interesting to crosslink materials with two types of vulcanizing agents – dicumyl peroxide and sulphur for obtaining comparable results. The concentration of dicumyl peroxide was varied between 0.5 - 2.0 wt%. It was found that the use of dicumyl peroxide in an amount of 1.0-2.0 wt% is accompanied by intense occurrence of crosslinking with the formation of an irreversible highly crosslinked structure in the polymer composition. Based on the evaluation of the melt flow index of the vulcanized compositions, it was found that at the concentration of dicumyl peroxide in an amount of 0.5 wt% they still retain the ability to flow. At concentrations above 0.5 wt% of dicumyl peroxide the polymer compositions completely lose the fluidity of the melt. It was found that with an increase in the sulphur concentration from 3.0 to 10 wt% the decrease in the melt flow index from 2.76 to 0.616 g/10 min is observed. It was found that the crosslinking process predominantly proceeds through double bonds of butadiene-nitrile rubber, thereby facilitating the production of dynamically vulcanized polymer materials with a unique combination of structure and properties. This was confirmed by the results of a study of the thermo-deformation characteristics of compositions, according to which a transition from the region of a high-elastic state to viscous-flow state is observed in all samples subjected to sulfur vulcanization. The results of the study make it possible to state that dynamic thermoplastic elastomers can be obtained only if the ratio of the components used in the polymer composition is correctly selected.

Abstract This paper reviews the utilization of waste rubber and waste plastics for the preparation of thermoplastic elastomers (TPEs). TPEs based on ground rubber tire (GRT), waste EPDM rubber, waste nitrile rubber, recycled rubber, latex waste, and waste plastics are described with respect to composition and physical properties. It is found that part of the rubber phase or plastics phase or both in the rubber-plastics blend can be replaced with corresponding waste polymer for the preparation of thermoplastic elastomers. In many cases, the materials prepared from waste polymers show properties comparable to those prepared from fresh polymers. However, in some cases, the materials prepared from waste rubber or waste plastics cannot be classified as TPEs, as the blend compositions show very low elongation at break. Modification of the waste polymer or the use of compatibilizers result in stronger composites.

A review of the scientific technical literature in the field of modern research on silicone rubber compositions with high temperature resistance, including those with fire-resistant properties, is presented. The polymer bases and heat-stabilizing and flame-retardant additives used in the developments, as well as methods for preparing rubber mixes and rubbers are shown. Features of compounding materials with a combination of heat resistance and fire-resistance are noted. The relevance of research for the needs of aviation equipment is shown.

A study was conducted in order to obtain a highly adhesive and highly elastic coating of the adhesive and sealing composition. Cooligomers of polyoxypropylene glycol and 4,4'-diphenyl-methane diisocyanate were obtained and their copolycondensation kinetics was studied. It has been established that the urethane formation reaction proceeds through a migration polymerization based on the addition of mobile hydrogen atoms of the polyester to the nitrogen atom. The morphology of the synthesized cooligomers was studied by IR spectroscopy. It was shown that the combination of cooligomer with butyl rubber (a copolymer of isobutylene and isoprene) increases the elasticity of the system, relieves shrinkage and increases the thermal and chemical resistance. In order to obtain an adhesive and highly elastic composite material, we studied mixtures of polyurethane cooligomer with butyl rubber (BK), which has high rates of heat resistance, elasticity and chemical resistance in aggressive environments. It was shown that when polyurethane copolymer is mixed with butyl rubber, a polymer system is formed, the macromolecules of which mechanically interact with each other to form so-called interpenetrating grids. This composition is also the very stable in aggressive environments, which makes its application promising. Comparison of the data of differential thermal analysis of the cooligomer and the composition of cooligomer + butyl rubber shows that the resulting composition is thermally more stable than the cooligomer. An important scientific and technical problem of improving the quality of adhesive compositions has been solved. Because of the study, recommendations have been developed for improving the properties of adhesive compositions that are competitive with existing analogues, according to the formulation of the structure, technology for the preparation and use of adhesive compositions. The compositions obtained in this way can be used in the production of polymer products for the petroleum and engineering industries.

To develop and create effective vibration-damping composite polymer materials (VDСPM) with high viscoelastic and strength properties, the choice of research objects to increase durability reduces vibration of parts and structures of machines consequently, the noise level in industrial premises is stated and substantiated. A method is described for studying the viscoelastic properties, adhesive strength, microhardness, impact strength of polymer coatings, and compositions based on them, filled with organomineral ingredients. The results of studies of the viscoelastic and physicomechanical properties of polymer composite materials based on epoxy polymers and an organomineral filler - rubber powder are presented. Based on complex analyzes and the obtained results of the study of the physicomechanical and viscoelastic properties of materials, several effective compositions of vibration-damping polymer materials using rubber powder have been developed.

Research has been carried out to assess the impact of mold fungi on polymer composite materials based on polypropylene produced by Omsk Polypropylene Plant LLC and unrefined natural rubber produced in Vietnam, grade RSS-1. The amount of natural rubber varied up to 15% of the mass. The fungal resistance of the compositions to the following types of fungi was assessed: Aspergillus niger, Aspergillus terreus, Aspergillus flavus, Chaetomium globosum, Paecilomyces variotii, Penicillium funiculosum, Penicillium chrysogenum, Trichoderma viredens. The decrease in the weight of the samples after incubation depends on the content of natural rubber in the composition. With the content of natural rubber in the composition in an amount of 1%, the average weight loss is 0.4% by weight, and when the content of natural rubber is 15% by weight. already ~ 2% of the mass. Starting with the addition of natural rubber in an amount of 1% by weight, the growth of fungi occurs, and the degree of their development is characterized by points 3-5. The resulting compositions are biodegradable, susceptible to the action of fungi, and, therefore, the manufacture of materials based on them will be an environmentally friendly alternative for further use.

Rutting is an important problem in Russia today. One of the ways to improve the properties of asphalt concrete mixtures and reduce wear on road surfaces is to modify the binder with polymer additives. The aim of the work was to test the selected compositions of MMAC mixtures containing bitumen modified with the addition of sevilene and rubber for rutting resistance, which make it possible to predict the formation of plastic rut. It was revealed that when using sevilen in its composition, with an increase in the concentration of vinyl acetate, the depth of the track increases in comparison with the industrial polymer-bitumen binder. It is shown that with the introduction of a complex additive based on sevilen and rubber into the binder composition, its rutting decreases and the service life of the road surface increases, which indicates a high elasticity of the complex-modified binder. In this work, the calculation of the service life of the coating before the formation of a critical rut requiring repair of the coating is carried out. It was found that in terms of the slope of the rutting curve and the proportional depth of the rut, the compositions with sevilene and rubber are not inferior to traditional industrial PBB.

Hevea brasiliensis is the most relevant source of natural rubber-based products in the world, and it is mostly found in Southeast Asia. This species is highly functional because its seeds can be utilized as a starting material for many essential applications related to polymer engineering and technology. The main practical compositions are its shell and kernel. The importance of each composition is varied based on the content of each structure. The kernel is predominantly composed of oil, where the oil can be utilized for the production of biofuel and to impart flexibility in many polymer-based composites. Furthermore, the carbon and lignocellulosic contents are heavily represented in the shell of the rubber seed, making the shell useful as a natural resource for carbon-derived applications.

Recently, environmental problems caused by the overproduction and consumption of synthetic polymer materials led to an urgent need to develop efficient methods for processing plastics. The accumulation of polymer waste for their subsequent incineration does not solve the problem due to the limited areas of landfills for waste storage. In addition, the incineration of polymer waste can cause toxic air pollution, which, in turn, does not contribute to an improvement in the environmental situation. Recycling plastics, although a more environmentally friendly waste disposal method, requires significant labor and energy costs and can be performed a limited number of times. Thus, the most promising solution to this problem is the creation of biodegradable polymers capable of degradation with the formation of simpler chemical structures (water, carbon dioxide, biomass, etc.), which are easily included in the metabolic processes of natural biological systems. The article provides an overview of the main trends in the creation of biodegradable composites for the needs of agriculture. Also, the article proposes a new composition based on polyethylene with natural rubber that surpasses existing biodegradable materials in a number of physical and mechanical characteristics and has the ability to complete biodegradation in 60 months. It is shown that the studies carried out to date indicate that these composites are highly promising for the creation of biodegradable packaging materials with good performance characteristics. Thus, it was concluded that further research on composites based on polyethylene and natural rubber is important.

Об’єкт дослідження: процес змішування поліетилен-каучукових композицій в одночерв’ячному екструдері. Предмет дослідження: вплив геометричних розмірів змішувальних елементів черв’яка на процес перемішування поліетилен-каучукових композицій в одночерв’ячному екструдері. Метою дисертаційної роботи є встановлення закономірностей якості змішування від геометричних розмірів змішувального елементу для підвищення ефективності проведення процесу змішування полімер–каучукових композиційних матеріалів. Наведено інформацію про походження проблеми змішування полімер–каучукових композицій та аналіз методики експериментальних досліджень. Сформульовано фізичну модель процесу гомогенізації в умовах деформації зсуву неоднорідної суміші каучуку з поліетиленом у робочих зазорах. Сформульовано математичну модель течії розплаву у робочих зазорах змішувального елементу при гомогенізації полімер–каучукових композицій, розроблено алгоритм та програму розрахунку математичної моделі процесу. Розроблено рекомендації щодо проектування нових конструкцій змішувальних елементів.
Object of research: the process of mixing polyethylene-rubber compositions in a single-screw extruder. Subject of research: the influence of geometrical dimensions of the screw mixing elements on the process of mixing polyethylene-rubber compositions in a single-screw extruder. The purpose of the dissertation is to establish the quality of mixing from the geometric dimensions of the mixing element to improve the effectiveness of the process of mixing polymer-rubber composite materials. Given the information on the origin of the problem of mixing polymer-rubber compositions and the analysis of experimental research methods. Formulated the physical model of the process of homogenization in the conditions of the deformation of the shift of the non-uniform mixture of rubber with polyethylene in working clearances. Formulated the mathematical model of the melt flow in the working clearances of the mixing element during homogenization of polymer-rubber compositions, developed the algorithm and the program for calculating the mathematical model of the process. Developed recommendations for designing new constructions of mixing elements.
Объект исследования: процесс смешивания полиэтилен-каучуковых композиций в одношнековом экструдере. Предмет исследования: влияние геометрических размеров смесительных элементов червяка на процесс перемешивания полиэтилен-каучуковых композиций в одношнековом экструдере. Целью диссертационной работы является установление закономерностей качества смешивания от геометрических размеров смесительного элемента для повышения эффективности проведения процесса смешивания полимер-каучуковых композиционных материалов. Приведена информация о происхождении проблемы смешивания полимер-каучуковых композиций и анализ методики экспериментальных исследований. Сформулировано физическую модель процесса гомогенизации в условиях деформации сдвига неоднородной смеси каучука с полиэтиленом в рабочих зазорах. Сформулировано математическую модель течения расплава в рабочих зазорах смесительного элемента при гомогенизации полимер-каучуковых композиций, разработан алгоритм и программа расчета математической модели процесса. Разработаны рекомендации по проектированию новых конструкций смесительных элементов.

Organic-Inorganic composite materials (OICs) are used to describe the group of materials synthesized from polymers and inorganic metal alkkoxides. The interests in these materials arised from the need to ‘combine' the physical properties of inorganic glass materials and polymers such that the resultant OICs have the strength of the inorganic glass and flexibiliy of polymeric materials. Sol-gel technique have been the technique of choice due to much of its advantages, in particular the low temperature reaction. This is very important when natural rubber and its derivatives are used as the polymer component of the OICs. Work in our laboratory has demonstrated that OICs form liquid natural rubber (LNR) and 50% epoxidised natural rubber (ENR-50) can be prepared from various metal alkoxides, such silicon, zirconium and titanium. The OICs can be prepared as flexible transparent films, nanofibers and nanobeads. This Chapter will describe the preparation techniques and the properties of these OICs from various compositions of one and more metal alkoxides in both LNR and ENR-50. The applications of these materials in PANI will be briefly described.