Investigation of the kinetics of heat treatment of epoxy polymers

Abstract

The study examines the effect of the concentration of modifiers (BDI) on the annihilation characteristics of cured epoxy polymers using the positron annihilation method. The results show that both the concentration and size of microcavity defects decrease, which can be explained by the formation of densely sewn areas due to the production of additional bridges. The supramolecular structure of the formed epoxy polymer is discussed, with the identification of several distinct areas, including polymer globules formed by stacking chains of simple polyester macromolecules around polymerization centers, and the interglobular space consisting of the ends of macro chains and low molecular weight products. The end groups of polymerization-cured epoxy polymers, such as double bonds of the vinylidene type, hydroxyl and unreacted epoxy groups, create conditions for the splitting of BDI in the interglobular space. The study also demonstrates that at optimal concentrations of modifiers, there is a decrease in the radius and concentration of micropore defects, as well as a general decrease in the proportion of free volume. The curing processes of epoxy polymers and their heat treatment in the presence of modifiers are investigated, with BDI having a significant effect on the formation of the epoxy polymer structure.