Investigation of the T sub ll (> T sub g) Relaxation in Homopolymers and Block Copolymers of Styrene by Torsional Braid Analysis.
Abstract
Investigation of the T sub ll (> T sub g) relaxation in amorphous polymers of styrene by the technique of torsional braid analysis has been reviewed. For the most part the relaxation behaves like the glass transition (T sub g) in its dependence on molecular weight, on average molecular weight in binary polystyrene blends, and on composition in a polystyrene homogeneously plasticized throughout the range of composition. Diblock and triblock copolymers also display a T > Tg relaxation above the Tg of the polystyrene phase. Two results in particular suggest that the T sub ll relaxation is molecularly based. 1) The temperature T sub ll is determined by the number average molecular weight for binary blends of polystyrene when both components have molecular weights below Mc (the critical molecular weight for chain entanglements). 2) Homopolymers, and diblock and triblock copolymers of styrene, have a T > T sub g relaxation at approximately the same temperature when the molecular weight of the styrene block is equal to that of the homopolymer. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1977
- Accession Number
- ADA048455
Entities
People
- J. K. Gillham
- R. F. Boyer
Organizations
- Princeton University