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Cyclization in crosslinking polymerization. I. Chain polymerization of a bis unsaturated monomer (monodisperse case)

1975; Wiley; Volume: 53; Issue: 1 Linguagem: Inglês

10.1002/polc.5070530109

1936-0959

Karel Dušek, M. Ilavský,

Microplastics and Plastic Pollution

Abstract Cyclization in the chain polymerization of bis unsaturated monomers has been treated by cascade formalism based on primary chains for a kinetically controlled reaction. The primary chains consist of repeat units bearing an unreacted (pendent) double bond and units engaged in effective branchings (crosslinks), or cycles. Calculation of the participation of the units of individual types is based on the probability for growing macroradicals of different lengths to react with double bonds of the monomer, or attached to other (branched) macromolecules, or with double bonds on the same growing macroradical and on primary chains already attached to it (multiple crosslinking). The cyclization probability is controlled by the conformational statistics of the linear sequence of bonds between the reacting functionalities. Correlations due to already existing cycles are not considered. Differential increments of units of different types are integrated. Relationships have been derived which characterize the degree of unsaturation, cyclization, and effective branching as a function of the degree of polymerization of the primary chains, chain flexibility, dilution, and conversion up to the gel point, and conditions for the gel point. In this part, systems with monodisperse primary chains have been treated, two variants for the calculation of the cyclization probability based on the average and variable composition of the growing macroradical have been discussed, and the effect of multiple crosslinking has been evaluated.