A Multifaceted Approach for Process Characterization of Polymer-matrix Composites

Abstract

During processing of advanced polymer-matrix composites, the matrix undergoes several phase transitions and possible phase separations. As curing progresses, a thermosetbased matrix changes from a high viscosity liquid to a viscoelastic rubber and eventually a hypo-elastic glass. Such progression of behaviour combined with the multiscale nature of composites is manifested as a complex and dynamic response at the laminate-level. As the need for process simulation of composites has become more apparent in recent years, so has the need to develop effective process characterization methods. A comprehensive review of characterization methods is presented in this study. Attention is given to the resin thermal expansion and cure shrinkage. Methods including Digital Image Correlation (DIC), Thermomechanical Analysis (TMA) and Digital Microscopy (DM) are discussed and compared. It is shown that a single approach cannot be used to characterize the response of material across all phases. It is also shown that by using a combination of these methods, a comprehensive understanding of material behaviour can be achieved. The effectiveness of such an approach is demonstrated by a cross-comparison of experimental results for the AS4/8552 prepreg system.