Investigation of the T(ll) (> T(g)) Relaxation of Homopolymers and Block Copolymers of Styrene by Torsional Braid Analysis.
Abstract
Investigation of the T (ll) (> T(g)) relaxation in amorphous polymers of styrene by the technique of torsional braid analysis is reviewed. For the most part the relaxation behaves like the glass transition 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 > T(g) relaxation above the T(g) of the polystyrene phase. Unlike the glass transition, the T(ll) relaxation appears to depend on the nature of the substrate. Two results in particular suggest that the T(ll) relaxation is molecularly based. (1) The T(ll) temperature is determined by the number average molecular weight for binary blends of polystyrene when both components have molecular weights below M(c) (the critical molecular weight for chain entanglements). (2) Homopolymers, and diblock and triblock copolymers of styrene, have a T > T(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
- Jul 01, 1979
- Accession Number
- ADA072075
Entities
People
- J. K. Gillham
Organizations
- Princeton University