Polymerization of vinyl monomers

A systematic study of the kinetics of photosensitized polymerization of vinyl monomers with the system Dye (erythrosin or acriflavine)-reducing agent (ascorbic acid), in the presence of oxygen and under buffered conditions (pH 6) in aqueous solution has been made. The determinations of the monomer disappearance, dye disappearance and of chainlengths of the polymers obtained against the different variables like light intensity, concentrations of monomer, dye, ascorbic acid, etc., have been made. A kinetic mechanism proposed for the overall reaction is discussed in the light of the experimental results and certain rate constants have also been evaluated.     

Modification of the mechanical properties of synthetic fibers by grafting vinyl monomers

Graft polystyrene has been synthesized on polypropylene fibers. The isometric heating curves of the grafted fibers have two maxima. The first is associated with the preserved oriented polypropylene structures, the second with the oriented structures formed directly in the process of polystyrene synthesis. The maximum stress corresponding to the latter maximum is proportional to the amount of polystyrene and the degree of orientation of the starting polypropylene and depends on the mechanical stress in the fiber during the process of polystyrene synthesis.Mekhanika Polimerov, Vol. 3, No. 6, pp. 963–969, 1967     

Mechanism of the increase in strength and heat resistance of oriented polymeric materials modified by graft copolymerization with vinyl monomers

The mechanical properties and structures of oriented films and fibers composed of polyethylene, polymethyl methacrylate, and other amorphous and crystalline polymers modified by the synthesis of uniformly distributed graft and block copolymers of methyl methacrylate, acrylonitrile, vinylidene chloride and other monomers have been the subject of a comparative investigation. The effect of the grafted polymers on the molecular mobility, relaxation processes, and solubility of the materials is explained by reference to a universal physical "crosslinking" mechanism. A theory of the interrelation between the structure and physical properties of the materials, the nature of the polymers, and the grafting conditions is developed and used to analyze the experimental data on a broad range of systems.V. I. Lenin Belorussian State University, Minsk. Translated from Mekhanika Polimerov, No. 6, pp. 968–975, November–December, 1973.     

Polymerization stresses in linear viscoelastic media

It is proposed to use a model of the hereditary type to take into account the stresses developing in the process of polymerization. The effect of the degree of polymerization (cure) on the viscoelastic properties of the material is taken into account by introducing a function analogous to the temperature shift function in time-temperature superposition. In this case the system of equations consists of the above-mentioned system of equations of viscoelasticity, the kinetic equation of the curing process, and the equation of heat conduction with allowance for the presence of sources and variable thermophysical characteristics.M. V. Lomonosov Moscow State University. Translated from Mekhanika Polimerov, Vol. 4, No. 4, pp. 716–723, July–August, 1968.     

Gelation of a Reversible Markov Process of Polymerization

In this paper a reversible Markov process as a chemical polymers reaction of two types of monomers is defined.By analyzing the partition functions of the process we obtain three different distributions of the average molecular weight,depending of the value of strength of the fragmentation reaction,and prove that a gelation of the process will occur in the thermodynamic limit.     

一类带扩散的聚合物模型的定性分析

本文研究一类带扩散的聚合物模型,并在参数γ＞0和γ＜0两种不同情形给出定性分析.主要运用抛物型方程比较原理和相应常微分方程的结论得到反应扩散方程的先验估计和渐近性分析.     

Graph theory and molecular distribution: Part I: copolycondensation of polyfunctional monomers bearing identical reactive groups

The equilibrium distribution for a random f-functional polycondensation system was derived by different probability arguments by Flory, Stockmayer, Good, Gordon, Whittle and others. The extension of these techniques to more complex systems involves abstract mathematics and often requires deriving probability generating functions. This study shows how Graph Theory allows one to obtain directly and readily theses molecular distribution functions in the most general systems of order I, i.e. consisting of various monomer units with different functionalities, all sites being identical and equireactive.     

Modelling the semi-batch vinyl acetate emulsion polymerization in a real-life industrial reactor

A detailed dynamic model of the polymerization reaction of vinyl acetate in a real-life industrial reactor is presented. With the recipe and the operating procedures observed in the factory as inputs, the model predicts with reasonable accuracy the final conversion, the average particle diameter, the solid content and the viscosity. The manual and semi-manual operations, and the decision process followed by the operator, are also modelled in order to replicate closely the process carried out in the factory. The model provides further insight into the reaction kinetics and allows us to make knowledge-based decisions. The model is intended to be used for the optimization of the policy of adding monomer in order to reduce the batch time.