English

Abstract

Crystallization rate of isotactic polystyrene (iPS) from molten and glassy state was studied by polarized optical microscopy (POM), differential scanning calorimetry (DSC) and light intensity measurement (LIM) techniques. Samples were melted at different temperatures and subsequently crystallized from molten or glassy states. In all cases, the crystallization rate shows a temperature dependent bell shaped curve. At low melting temperatures, the crystallization rate is faster, due to insufficient melting, where the surviving crystals accelerate the crystallization process. With the increasing melting temperatures, crystallization rate slows down. At high melting temperature, the crystallization rate from glassy state is faster than from the molten state. The crystallization rates from molten states strongly depend on the crystallization temperatures and melting temperatures, where it depends only on crystallization temperatures in case of glassy states. These crystallization rates are discussed using Avrami equation.