Premium
The reactive modification of polyethylene. I: The effect of low initiator concentrations on molecular properties
Author(s) -
Suwanda D.,
Balks S. T.
Publication year - 1993
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.760332402
Subject(s) - degree of unsaturation , branching (polymer chemistry) , linear low density polyethylene , reactive extrusion , molar mass distribution , polyethylene , dispersity , materials science , extrusion , high density polyethylene , polymer chemistry , low density polyethylene , chemical engineering , analytical chemistry (journal) , polymer , organic chemistry , chemistry , composite material , engineering
Commercial samples of high density, linear low density, and low density polyethylene were modified by injection of low concentrations of free radical initiator during extrusion. Molecular properties monitored included molecular weight distribution, degree of unsaturation, and branching. When the polyethylene teed to this reactive extrusion process had similar values of M w , but varying polydispersity, degree of branching and degree of unsaturation, the magnitude of the change in molecular weight distribution was found to be in the following order: HDPE 1 > LDPE2 > LLDPE. In general, terminal vinyls enhanced molecular weight increase, and branching promoted degradation. However, for a second high density polyethylene sample with M w = 154,000 (rather than the previous sample's M w of 85,600), the change in molecular weight distribution was small and located at the lower molecular weight end. This work provided data for the kinetic model development detailed in Part II.