Compression Molded Polyurethane Block Copolymers. 1. Thermal and Thermomechanical Properties
Abstract
The thermal and thermomechanical properties of a series of compression molded MDI/BDO/PPO-PEO segmented polyurethane block copolymers are reported as a function of hard segment content. Correlations between these properties show that the hard microdomain morphology is continuous for hard segment contents exceeding ca. 40%. At high program temperature rates, DSC thermograms exhibit a single high temperature endotherm corresponding to the melting of an extended form of MDI/BDO crystal. Multiple endotherms are observed at low DSC scan rates. For high hard segment content specimens, catastrophic softening is coincident with the onset of the first high temperature endotherm. The primary softening point for materials with discrete hard microdomains occurs at the soft microphase Tg. The soft microphase Tg is a minimum for a hard segment content of 50%. The apparent hard microdomain Tg decreases monotonically with increasing hard content and is consistent with heat capacity data for the soft microphase Tg which indicates increased incorporation of soft segment material into the hard microdomain for higher hard segment content materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 27, 1990
- Accession Number
- ADA220068
Entities
People
- A. F. Galambos
- J. T. Koberstein
- L. M. Leung
Organizations
- University of Connecticut