Principal Regularities of the Aging Behavior of Glass-Filled Polyamides

Abstract

The results of research on the aging of glass-filled polycaproamide materials are reviewed. The data on the influence of the type and concentration of glass fillers, stabilizers, and modifiers of different chemical structures, used in the manufacture of glass-filled polyamides, on the formation of the supramolecular structure of polyamides and porous structure of complex composites are summarized. Irreversible changes in the performance and mechanical properties of glass-filled polyamides are shown to be caused by damage accumulation on the glass-fiber–polyamide interface. This damage manifests itself in an increase in the volume and surface area of pores and a decrease in their average size due to crystallization and re-crystallization processes, which occur during initial storage time (1–3 years) and involve changes in crystallinity and ratio between different crystallinity forms in polyamide-6, as well as due to seasonal and daily temperature changes during further storage periods. A strong impact of storage conditions (temperature and humidity) on the level of polymer degradation and structural transformations is revealed. The mechanism of humidity (as a climatic factor) effect is established. A change of the relaxation mechanism at temperatures above 140°C (transition from the kinetic to diffusion region) is demonstrated. The main fields of practical application of the results presented in this paper are outlined.