Characterization of Thermotropic Liquid Crystalline Polymer Blends by Positron Annihilation Lifetime Spectroscopy

Abstract

ABSTRACTPositron annihilation lifetime spectroscopy (PALS) is used to investigate polymer-based molecular composites of two separate thermotropic liquid crystalline polymers (TLCPs) and the thermoplastic matrix polyetherimide. Trends in PALS spectral components obtained isothermally at 20°C and 120°C as a function of TLCP content are discussed as a function of free volume and molecular structure. Differential scanning calorimetry was employed as a complementary technique to investigate the differences in miscibility of the two systems and possible effects on positron lifetime values.