Simplified model of stress-induced crystallization kinetics of polymers

A stress-induced crystallization model for semicrystalline plastics is proposed based on the theory that stress-induced orientation of molecules and chains increase the melting temperature of thermoplastics, and hence, the supercooling which is the driving force for crystallization. By assuming that the effect of stress on crystallization is only by increasing the melting temperature, the basic quiescent-state crystallization equation can be directly applied to model stress-induced crystallization kinetics. The model has a minimum of experimentally based constants. A simple experimental technique, such as a rotational rheometer, can be used to determine the melting temperature shift. The model predicts the most prominent features of stress-induced crystallization. The main advantage of the model is that the parameters in the quiescent-state crystallization model do not change. Consequently, the parameters in the melting temperature shift model are easy to determine, and unknown constarits are kept to a minimum.