Peculiarities of Formation Kinetics and Structure of Linear Polymers in Confined Intranetwork Space During Synthesis of Sequential Semi-interpenetrating Polymer Networks

摘要

Peculiarities of formation kinetics of sequential semi-interpenetrating polymer networks (IPNs) based on polyurethanes with different crosslink densities and linear polystyrene, poly(butyl methacrylate), and poly(methacrylic acid) have been studied. The molecular-mass distributions of linear polymers developed in semi-IPNs are examined by size-exclusion chromatography. Viscoelastic and thermophysical properties of sequential semi-IPNs were investigated by the method of dynamic mechanical analysis and differential scanning calorimetry. The experimental data show the dependence of the kinetic parameters of polymerization and relaxation properties on M_c. As a result, the material structure may change in a wide range from a nearly single-phase system to a two-phase one. Small angle X-ray scattering measurements indicate that there is symbate dependence between the degree of segregation of components of sequential semi-IPNs and their microheterogeneous structure on the internetwork space. Two hierarchical heterogeneity levels are found to exist in polymer networks, and the features of each of these levels are analyzed.