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On the effect of mechanical energy on the degradation of polyethylene in the solid state and in the melt
Author(s) -
Holmström Arne,
Andersson Arne,
Sörvik Erling M.
Publication year - 1977
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.760171006
Subject(s) - materials science , branching (polymer chemistry) , gel permeation chromatography , viscometer , polyethylene , composite material , molar mass distribution , molding (decorative) , shear (geology) , polymer , degradation (telecommunications) , viscosity , telecommunications , computer science
The influence of mechanical forces on structural changes in commercial grades of high and low density polyethylenes was investigated by using extremely high shear rates (>2 × 10 4 S −1 ) during processing in a special injection molding machine and by long‐term loading at ambient temperature. Changes in molecular weight distribution (MWD) and the degree of long‐chain branching (LCB) were followed by gel permeation chromatography and viscometry. No effect of the mechanical forces was observed either in the long‐term loading or in the processing. At temperatures exceeding 280°C the small changes noted in MWD and LCB wrere found to be entirely due to thermal de radation.