On thermo-fluctulation description of chemical reactions in polymers

Investigations of polydienes with various chemical structures and microstructures were carried out, and interrelations of molecular-structural characteristics of polydienes with their macroscopic properties in thermo-oxidation processes were shown. An experimental-formal approach to substantiation of cross-linking and destruction depth of carbon-chain linear polydiene macromolecules is proposed. The extrapolation value of the molecular weight of the chain ensuring activation of chemical reactions of vulcanization and oxidation was obtained. It is proposed to use the criterion of destruction for calculating the number of chain splinters resulting from macromolecule ruptures

Simulation of polidiene oxidation kinetics

Synthetic isoprene rubber (SIR) is similar in structure and to the properties of natural rubber (NR). Currently, it can almost completely replace NR in the production of automobile tires and rubber products. An urgent task is to study the aging processes of polymers and their products, assess the impact of various factors on the oxidative stability of polymers and the selection of effective ways to protect polymers from aging. We simulated aging of inhibited (commodity) and reprecipitation (purified) polyisoprene

On thermo-fluctulation description of chemical reactions in polymers

Investigations of polydienes with various chemical structures and microstructures were carried out, and interrelations of molecular-structural characteristics of polydienes with their macroscopic properties in thermo-oxidation processes were shown. An experimental-formal approach to substantiation of cross-linking and destruction depth of carbon-chain linear polydiene macromolecules is proposed. The extrapolation value of the molecular weight of the chain ensuring activation of chemical reactions of vulcanization and oxidation was obtained. It is proposed to use the criterion of destruction for calculating the number of chain splinters resulting from macromolecule ruptures

Simulation of polidiene oxidation kinetics

Synthetic isoprene rubber (SIR) is similar in structure and to the properties of natural rubber (NR). Currently, it can almost completely replace NR in the production of automobile tires and rubber products. An urgent task is to study the aging processes of polymers and their products, assess the impact of various factors on the oxidative stability of polymers and the selection of effective ways to protect polymers from aging. We simulated aging of inhibited (commodity) and reprecipitation (purified) polyisoprene

The study of characteristics of powders of polymers for 3D printing

One of the biggest challenges is to find ways of recovering the expensive powder. With this aim, we needed to find out what happens with polyamide powder in the chamber of the printer and what processes affect raw materials, thereby impairing the physico-mechanical properties. In order to answer these questions, we conducted a number of studies. Articles of mixtures with a high aspect ratio of the secondary powder lose their properties: their surface is rough, increased fragility, there is a possibility of deformation of details. We carried out studies of the powder based on polyamide-12, applied by JSC "Center of technological competence of additive technologies" of the city of Voronezh, brand PA2200 modified. Material white powder, odourless. An increase in the degree of crystallinity from recycled polymer is considered an anomaly. But the violation of this trend due to the peculiarities of the technology of selective laser sintering. Thus, prolonged exposure of the powder in the chamber at a temperature close to the melting point, followed by a long cooling to room temperature represents the ideal conditions for the growth of crystalline phase. The research was able to identify differences due to deterioration of the physico-chemical properties of the powder after processing. The most important is the agglomeration of particles of the secondary powder in relation to the primary. In this regard, powder, already passed the stage of processing, an increase in the melting temperature, which causes defects in the fabricated parts: as the capacity of the carbon laser melting powder particles is fixed, its energy is not sufficient for the occurrence of the endothermic reaction caused by melting of the secondary powder. Thus, the powder particles only partially fused, whereby the resulting products of the observed increase in fragility

Optimization of the properties of radiation regenerate used in elastomeric roofing materials

The results of research on the problem of regeneration of rubbers based on butyl rubber are presented. The advantages of radiation destruction of butyl rubbers are substantiated. The diaphragms of the vulcanizer formers, which were exposed to ionizing radiation at the Co60 source, were chosen as the objects of the study. The effect of the irradiation dose on the technological properties of the recovered regenerates and the elasto-strength properties of the compositions based on them was studied. It is established that the treatment of diaphragm rubbers with a dose of 50, 70 kGy provides an optimal set of properties. An analysis of the structural changes that occur during irradiation of spent diaphragms showed that at high doses of 20-40 kGy a high level of high-elastic deformation remains, while a sufficient number of crosslinked structures remain. At an irradiation dose > 40 kGy, the destructant acquires the ability to roll. The effect of machining on diaphragm rubbers subjected to radiation exposure has been studied. It was found that processing on rotor-type equipment reduces the viscosity of the compositions. The procedure for optimizing the composition of roofing rubber compounds was performed depending on the irradiation dose of diaphragm rubbers and the dosage of the regenerate. Regression statistics and variance analysis confirmed the adequacy of the model and the significance of the coefficients of the equation. The error in the calculations for the tensile strength was 0.65%, for the MI viscosity, 1.23%. On the basis of the developed regenerants, roofing rubber compounds were made and their properties were investigated. It is shown that the use of butyl rubber regenerants in a recipe of roofing rubbers with a dose of 50, 70 kGy provides the required level of properties and reduces their cost price. It is recommended to use these materials in the composition of hydro-insulating materials to improve technological properties and reduce their cost