Effect of molecular weight on crystalline structure in thermotropic random copolymers

Abstract

The characteristics of thermotropic liquid crystalline p-oxybenzoate/2,6-oxynaphtoate copolymers of similar composition with degrees of polymerization in the range of 25-150 were studied by TEM. Measurement of the crystallite dimensions shows that the thickness is not a strong function of the DP, whereas the length appears to become a linear function of DP when DP≥65. The breadth of each L c distribution also decreases with DP, suggesting more uniform crystallites are present in high molecular weight polymers