Study of Thermal Aging of the PCM Using Acoustic Emission and Optical Microscopy

Abstract

This work presents results of a study of the influence assessment based on the recorded acoustic emission (AE) parameters of thermo-oxidative aging conditions on the destruction process of a polymer composite material (PCM). The objects of the study were specimens cut from a fiberglass reinforced plastic (FGRP) plate. The plate was made by vacuum infusion technique using Derakane 411-350 resin and 9 layers of St-62004 glass fabric. Specimens aging were done by holding in a muffle furnace for 96 hours at temperatures of 60, 100, 120, and 200 ° C. Mechanical test was the three-point static bending method. For the AE recording was used a hardware-software complex developed at KnASU. The AE signal Fourier spectra were two-stage clustered with the self-organizing Kohonen map according to the technique previously developed and tested by the authors. The types of the PCM structure damage were characterized by the obtained clusters centroids. The fracture process kinetics is described depending on the conditions of thermo-oxidative aging and based on the accumulation of clusters during mechanical tests. The negative influence of high temperatures on the polymer matrix degradation, leading to a decrease in the ability of the matrix to effectively distribute internal stresses over the PCM volume due to the adhesion corruption with the reinforcing material, has been established.