Role of Molecular Architecture on Mechanical Failure of Glassy/Semicrystalline Block Copolymers: CEC verses CECEC lamellae.
Abstract
The bulk mechanical properties of lamella forming CEC triblock and CECEC pentablock copolymers were evaluated. The two systems were initially tested in the polydomain, "multi-grained" state and were found to have very similar mechanical properties. The polymer samples were then processed with reciprocating shear leading to long-range domain orientation and a "single grain" state. Mesophase structure characterization and strain-induced structural changes were determined using 2-D small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM). Bulk mechanical properties of the multi-grained and single-grained samples were determined using modified ASTM tensile tests. Although the triblock and pentablock materials where nearly mechanically indistinguishable in the multi-grained state, significant enhancements in strength were obtained from the pentablock architecture along certain strain directions with the single-grain materials.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2003
- Bibcode:
- 2003APS..MARK17009B