Premium
Influence of long‐chain branching on the viscoelastic properties of low‐density polyethylenes
Author(s) -
Wild L.,
Ranganath R.,
Knobeloch D. C.
Publication year - 1976
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.760161206
Subject(s) - branching (polymer chemistry) , low density polyethylene , materials science , viscoelasticity , melt flow index , intermolecular force , swell , polymer , long chain , elasticity (physics) , die swell , polymer chemistry , thermodynamics , composite material , polymer science , molecule , organic chemistry , chemistry , copolymer , extrusion , physics
Melt How data has been determined for a series of fractionated and whole low density polyethylenes which has been characterized in terms of their molecular weights and degree of long‐chain branching, (LCB). The resulting data indicate that low LCB influences melt flow both through a reduction in molecular size and an increased level of intermolecular interaction. Die swell measurements on whole polymers indicate an increase in melt elasticity with increase in degree of LCB for samples of similar melt flow (MI). Comparison of GPC data with observed die swell characteristics indicates that die swell is a molecular size dependent property and independent of intermolecular entanglement effects, suggesting that the measurement of elastic properties of LDPE melts will provide a means of determining relative degrees of LCB for commercial resins.