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Head to head polymers IX: The rheological behavior of H‐H and H‐T atactic polystyrenes
Author(s) -
Jacovic M.,
Vogl O.
Publication year - 1978
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.760181109
Subject(s) - polystyrene , materials science , polymer , rheology , dynamic mechanical analysis , polymer chemistry , shear stress , rheometry , composite material
The rheological behavior of a sample of H‐H polystyrene of M n of 41,000 and a M w /M n of 2 was compared at 160 and 190°C with a sample of H‐T atactic polystyrene of similar molecular weight. The melt viscosity of H‐H polymer (unlike the H‐T polymer) was non‐Newtonian at low stresses and decreased more rapidly with stress. This observation seems to indicate a stiffer polymer chain for the H‐H polystyrene. The flow activation energy ( E *) of H‐H polystyrene was found to be dependent on the dynamic shear stress and decreased with increasing dynamic shear stress. The dynamic shear storage modulus of the H‐H polymer has a smaller increase of G ′ with ω than that of the H‐T polystyrene.