Crystallization and Melt Kinetics for Process Modelling of PEEK Matrix Composites
Process models of composite materials are useful tools for ensuring optimum process conditions and minimizing production risks and costs. In recent years, there has been growing interest in using thermoplastics, such as PEEK composites, in aircraft structures. In contrast to the commonly used thermosets, during the heat up process the thermoplastic material continuously melts and recrystallizes, while during cool down crystallization occurs.A major component of process modelling platforms for thermoplastics is the crystallization and melt kinetics model. Different crystallization models are available in the literature. Most models deal with isothermal and constant cooling rate non-isothermal crystallization separately and do not consider the induction time of crystallization. Also very little work has been done for studying melt kinetics quantitatively.In this study, we investigate the crystallization and melt behaviour of PEEK-AS4 composites using isothermal and non-isothermal DSC experiments. A rate-type crystallization kinetics model is presented which is capable of predicting melt crystallization, cold crystallization and recrystallization. An empirical model from the literature and the additivity rule are adopted for predicting the induction time. Also a melt model is presented which will be used along with the crystallization kinetics model for predicting the degree of crystallinity. It is shown that model predictions are in good agreement with experimental results.
Authors: Kamyar Gordnian, Reza Vaziri, and Anoush Poursartip
Conference: SAMPE Seattle 2017