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Thermal and mechanical modification of LDPE in single‐screw extruder
Author(s) -
Ono Kazuya,
Yamaguchi Masayuki
Publication year - 2009
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.29980
Subject(s) - low density polyethylene , materials science , viscoelasticity , plastics extrusion , composite material , polyethylene , shear (geology) , polymer , chain scission , polymer chemistry
The effect of processing history in a single‐screw extruder on molecular characteristics was studied by employing commercially available low‐density polyethylene with no additives. Generation of long‐chain branch, which is responsible for the neck‐in phenomenon and draw resonance, is indicated by nonlinear viscoelastic properties of the extruded samples. Consequently, the processed samples show higher level of elastic property than the original pellet. However, thermal analysis revealed that there is no change in the distribution of short‐chain branch. Moreover, both chain scission and cross‐linking take place, and the chain scission is predominant above 320°C. Furthermore, processing history at low temperature depresses the melt elastic nature, although primary molecular structure is unchanged. This would be attributed to shear modification phenomenon. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009