Characterization of Thermotropic Liquid Crystalline Polymer Blends by Positron Annihilation Lifetime Spectroscopy
Abstract
Positron annihilation lifetime spectroscopy (PALS) has been used to investigate polymer-based molecular composites of two separate thermotropic liquid crystalline polymers (TLCPs) and the thermoplastic matrix polyetherimide. Variations in PALS spectral components were observed as a function of both TLCP content and temperature and are discussed as a function of free volume and molecular structure. It has been shown that these differences, between the matrix and reinforcing phase, has substantial influence on the localization and annihilation of o-Ps. The more miscible HX4000 composites exhibited TLCP dominated lifetime characteristics at room temperature. Differential scanning calorimetry, used as a complementary characterization technique to PALS to investigate the differences in miscibility of the two systems and possible effects on lifetime values, has shown that the. greater miscibility exhibited by the HX4000 system over the Vectra system provides the potential to form composites on a size scale closer to the molecular level.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 17, 1992
- Accession Number
- ADA253616
Entities
People
- Phillip L. Jones
- Robert A. Naslund
Organizations
- Duke University