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The degradation of polystyrene during extrusion
Author(s) -
Arisawa Kunio,
Porter Roger S.
Publication year - 1970
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1970.070140402
Subject(s) - polystyrene , extrusion , degradation (telecommunications) , gel permeation chromatography , activation energy , rheometer , materials science , molar mass distribution , composite material , shear rate , shear stress , shear (geology) , polymer chemistry , rheology , polymer , chemistry , organic chemistry , telecommunications , computer science
An investigation was made of the magnitude and mechanism of shear degradation of a narrow distribution, high molecular weight ( M w = 670,000) polystyrene. An Instron rheometer was used to perform the extrusion at temperatures from 164° to 250°C. The change in molecular weight distribution was studied by gel permeation chromatography. The maximum shear stress employed was 5.83 kg/cm 2 . It was found that degradation could be induced at high stress at temperatures of 50°C lower than degradation of polystyrene would occur exclusively due to thermal forces. An activation energy for the degradation, calculated at constant shear rate, was +20.2 kcal/mole. The direction and magnitude of this value are consistent with degradation induced through a mechanical reduced activation for thermal degradation.