A Predictive Model for Heat Flow During Crystallization of Semi-Crystalline Polymers

Abstract

Crystallization plays an important role in polymer processes such as fiber spinning, injection molding and extrusion. The morphology of the crystalline phase obtained influences the mechanical and physical properties of the material. The energy or the heat flow at the liquid-solid interface during crystallization plays a key role in controlling the kinetics and subsequently influencing the morphology of the transforming material. However, formulating the problem using Stefan's approach with constant interface temperature is not sufficient for semi-crystalline matenals. In this paper, a numerical approach is taken to investigate the influence of crystallization kmetics, processing conditions and varying thermo-physical properties on the movement of the crystallization front. The change in crystallinity is modeled by modifying the crystallization temperature by relating it to the overall cooling rate of a hypothetical control volume in the crystalline domain. The results are compared with the analytical solutions and experimental studies reported in the literature.

Two-Dimensional Finite Element Model of the Pultrusion Process

“…A one-dimensional heat transfer model is also treated, and the solution is compared with that of the two-dimensional model. The governing equation is from Hackett and Prasad (1989), with the heat of reaction term added (Erhun and Advani, 1990) In Equation (11), all thermal properties are determined using Equations (3) through (7). This is another point that is different from the formulation of Hackett and Prasad (1989).…”