Кинетика окисления полиизопрена в присутствии активных добавок

Analysis of changes in the structure and properties of polyisoprene films was carried out. The samples contained chemically active additives (antioxidants, antiscorchings) and were subsequenly warmed up.Проведен анализ изменения структуры и свойств пленок полиизопрена, содержащих химически активные добавки (противостарители, антискорчинги) с последующим прогревом образцов

Элемент согласования волноводной линии передачи с диодом

The article deals with the issues of matching a waveguide transmission line with millimeter wave diodes. The implementation of the transition of a rectangular waveguide to a microstrip switching line in the form of a line of the fin-line type is described. The computer simulation results of the transmission coefficient module of the developed element and the standing wave coefficient by voltage separately for the transition from a rectangular waveguide to a microstrip transmission line and as part of an amplitude detector are shown. A joint application of the developed element with a microstrip detector based on a Schottky diode in the frequency range from 118.1 to 178.4 GHz is proposed. The results of measuring its parameters and the results of determining the sensitivity are given, as well as the evaluation of the results obtained is performed. The obtained results proved the possibility of using the matching element of a waveguide transmission line with a diode in the millimeter wavelength range. Рассмотрены вопросы согласования волноводной линии передачи с диодами миллиметрового диапазона длин волн. Описана реализация перехода с прямоугольного волновода на микрополосковую линию передачи в виде линии типа фин-лайн. Показаны результаты компьютерного моделирования модуля коэффициента передачи разработанного элемента и коэффициента стоячей волны по напряжению отдельно перехода с прямоугольного волновода на микрополосковую линию передачи и в составе амплитудного детектора. Представлена реализация совместного применения разработанного элемента с микрополосковым детектором на базе диода Шоттки в диапазоне частот от 118,1 до 178,4 ГГц. Приведены результаты измерения его параметров и определения чувствительности. При оценке полученных данных подтверждена возможность применения разработанного элемента согласования волноводной линии передачи с диодом в миллиметровом диапазоне длин волн

Development of a mathematical model of two-phase polymer curing systems

The formation a heterogeneous structure in two-phase elastomer composites was studied. Computer modeling of curing system in a set of five reaction–diffusion equations was carried out. In numerical experiments it is shown that density of the crosslinking of the entire system increases slower than the cure in the absence of curative’s diffusion, and the cure rate and the total degree of crosslinking of the composite as a whole is reduced

Modification of nitrile butadiene rubber at the stage of its allocation

Search for additives that increase the wear resistance of rubbers is relevant. It is known that the introduction of hollow corundum microspheres (NCM) into rubber reduces the wear of rubber products. The uniform distribution of small amounts of microspheres in rubber by traditional "dry" mixing in a rubber mixer or on rollers is difficult. Microspheres were introduced into rubber at the stage of its separation from latex. The work consisted in the selection of thickeners capable of holding the NSM in rubber latex SCN-18SNT at the stage of its coagulation, and evaluation of physical and mechanical properties of rubbers in the presence of NCM. The retention capacity of thickeners of polyacrylamide (PAA), carboxymethylcellulose (CMC) and polyvinyl alcohol (PVA) was determined. Thickened latex was coagulated in the presence of microspheres with polymeric coagulant and sulfuric acid. When filling the polymer with microspheres, it is preferable to use a PAA thickener. The yield of microspheres in rubber using thickeners PAA, CMC and PVA was 71.1, 66.5 and 38.7% , respectively. The physico-mechanical characteristics of rubbers based on SKN-18SNT in the presence of microspheres introduced both as a "dry" method in rubber and at the stage of its isolation from latex are determined. The presence of microspheres in an amount of 4.4-4.7% by weight. on rubber, did not affect the hardness and elasticity of rebound rubbers. It has been confirmed that the presence of microspheres, especially those introduced from the latex rubber release stage, provides an increase in abrasion resistance. In turn, the presence of microspheres in rubber with traces of polyacrylamide provided an increase in the resistance of rubbers to tearing, the modulus at 100 and 200% elongation with a decrease in the elongation at break

Modeling the kinetics of vulcanization polydienes

A model of vulcanization kinetics, which allows describing the kinetic curves of any form and on the basis of economical laboratory experiment analytically evaluate the kinetics of isothermal curing was proposed. In studying the kinetics of vulcanization, we assumed that the individual stages of the vulcanization process differ significantly speed and to determine the parameters on reometric curve isolated several areas. It allows to describe the process of a set of simple coupled first and second order vulcanization reactions

Development of mathematical model of curing two-phase polymeric systems

During research of kinetics of curing of two-phase elastomeric composites the new kinetic model, allowed to explain heterogeneity of the grid which was formed in this process of curing crosslink was developed. In numerical experiments it is shown that average extent of sewing together of all system increases more slowly, than when curing in lack of diffusion of vulcanizing substances, and the speed of curing and the general extent of sewing together of a composite as a whole decreases

WAYS TO OBTAIN AMIDES CONTAINING SALTS 3D-METALS BASED ON TALL OIL ROSIN AND STUDYING THEI INFLUENCE ON THE PROPERTIES OF THE SYSTEM "RUBBER - BRASSED METAL CORD"

Summary. This article discusses how to obtain amide-containing salts of 3d-metals based on tall rosin. A scheme of obtaining amide containing salts 3dmetals. The scheme of obtaining amide-containing salts of 3d-metals presented here. Ammonolysis maleopimaric acid was carried out, the technological parameters of the process were identified. Found that the process of ammonolysis affected by the following controlled technological factors: the ratio of the components, the temperature of the reaction medium and the duration of holding ammonolysis. The results of studies of the effect of additives on the received technical and technological properties of the elastomer compositions, adhesion and corrosion resistance rubber-systems are presented. The most efficient promoters are metalcord-rubber adhesion systems for use in the manufacture of tires fitted. Providing the necessary technological properties of manufacturing rubber compounds achieved when using elastomeric compositions consisting of a cobalt salt of amide MTC. Found that necessary to adjust the composition of the vulcanizing system using the synthesized compounds. It was revealed that the elastomeric composition comprising cobalt salt of amide maleated rosin and cobalt naphthenate are less susceptible to oxygen and air at elevated temperature compared to rubber containing salts Mn (II) and Cr (III) amide MTC. The results of studies of bond strength rubber with steel showed that the adhesive properties of rubber-systems with the test components depend on the dosage and rubber compound. It was determined that the introduction of salts of Co (II), based on amide maleated tall oil rosin at a dosage of 1.5 wt. parts per 100 wt. phr produces indicators adhesion and corrosion properties at the level of those with industrial modifier cobalt naphthenate. The results of research of obtained compounds influence on the technical and technological properties of the elastomer compositions, adhesion and corrosion resistance of rubber-cord systems are given

CREATING ACTIVATING SYSTEMS FOR THE EFFICIENT VULCANIZATION OF ELASTOMERS

Results of the study vulcanization of polydienes were presented. Vulcanization activators role in the formation of the actual curing agents and the formation of the spatial structure of the vulcanizates was considered. It is shown that to be effective requires the use of sulfur-vulcanization of zinc-containing vulcanization activators with a developed surface, capable of uniformly dispersed in a medium rubber. Activating sulfur vulcanization system elastomers as alloys of zinc oxide with fatty acids and their derivatives, modified halogenated compounds have been developed. Experimental vulcanization activators were tested in formulations of rubber compounds based on styrene butadiene rubber. Found that the use of experienced vulcanization activators enhances the cure rate and improved tensile properties, elastic rubber presumably due to the formation of a network structure of the cross-linking of different nature and energy. It is noted that the use of the experimental products enables products to reduce the vulcanization time by 7-10%. The possibility of reducing the dosage formulation activators in rubber vulcanization by using effective activating systems. The possibility to reduce 4-5 times the content of environmentally dangerous zinc oxide in rubber products and im-proved manufacturing techniques of rubber compounds by the use of experimental products in non-dusting form

Synthesis and properties of butadiene-alpha-methylstyrene thermoplastic elastomer

Butadiene-α-methylstyrene block – copolymer – a thermoplastic elastomer (TPE-R DMST) occupies a special place among the ethylene – vinyl aromatic block copolymers. TPE-R DMST comprising as plastic – poly-α-methylstyrene unit and elastic – polybutadiene block. TPE-R DMST has high heat resistance, flexibility, abrasion resistance compared to butadiene-styrene thermoplastic elastomer (TPE DST). The synthesis of block copolymers of butadiene and α-methylstyrene was carried out. The process of polymerization the α-methylstyrene characterized the high speed of polymerization in polar medium and low reaction speed in hydrocarbon solvents. Anionic catalyst nbutyllithium (n-BuLi) and high concentration – 60–80% α-methylstyrene in the mixture influenced by synthesis of the 1st block of TPE-R DMST, it’s technologically difficult. Found that the low temperature of polymerization α-methylstyrene (+61 o C), the reversibility of these reactions and the high concentration of residual monomer are very importance. It was revealed that a high polymerization rate α-methylstyrene can be achieved by conducting the reaction in a hydrocarbon solvent with polar additives compounds such as tetrahydrofuran (THF) and methyl tert-butyl ether (MTBE). The conditions for the synthesis of P-DMST were developed. The kinetics of polymerization for the first DMST-P unit was obtained. Analysis of physical and mechanical properties DMST-P samples was conducted. The optimum content of bound α-methylstyrene block copolymer provides a good combination of properties in a relatively wide temperature range. The tensile strength at normal and elevated temperatures, the hardness and the stiffness of the polymer increased by increasing the content of bound α-methylstyrene. The elongation and the elasticity reduced by increasing the content of bound α-methylstyrene

Influence of cure activator on the structure and properties of rubbers

The influence of vulcanization activator type on the properties of the compositions and elastic-strength characteristics of rubber was studied. Found that the modification of zinc oxide as the basis of actual formation curing vulcanization agents leads to an increase of vulcanization active centers, providing an increase in the velocity of rubber vulcanization and improvement of physical and mechanical rubber’s properties