z-logo
Premium
Investigation of the T u (>T g ) relaxation in homopolymers and block copolymers of styrene by torsional braid analysis
Author(s) -
Gillham J. K.
Publication year - 1979
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760191015
Subject(s) - polystyrene , copolymer , materials science , styrene , polymer chemistry , glass transition , relaxation (psychology) , polymer , amorphous solid , crystallography , composite material , chemistry , psychology , social psychology
Investigation of the T u (>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 ( T 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 > T g relaxation above the T g , of the polystyrene phase. Two results in particular suggest that the T u relaxation is molecularly based. (1) The T u 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.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here