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Thermal oxidation‐induced long chain branching and its effect on phase separation kinetics of a polyethylene blend
Author(s) -
Niu YanHua,
Wang ZhiGang,
Duan XiaoLi,
Shao Wei,
Wang DuJin,
Qiu Jie
Publication year - 2010
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.32664
Subject(s) - branching (polymer chemistry) , polyolefin , materials science , rheology , polymer chemistry , kinetics , polyethylene , copolymer , phase (matter) , chemical engineering , polymer , composite material , chemistry , organic chemistry , physics , layer (electronics) , quantum mechanics , engineering
Thermal oxidation‐induced long chain branching (LCB) during the molding processes for polyolefin copolymer poly(ethylene‐co‐butene) (PEB) and its blend with another polyolefin copolymer poly(ethylene‐co‐hexene) (PEH/PEB 50/50 blend, denoted as H50) was investigated mainly by rheological measurements. LCB with different levels could be introduced on PEB backbones by changing the molding temperature and/or molding time, which could be sensitively characterized by changes of rheological parameters, that is, storage modulus G ′ and complex viscosity η*. Thermal oxidation‐induced LCB of PEB in H50 samples could largely influence the phase separation kinetics. Rheological measurements and phase‐contrast optical microscope observations coherently indicated that thermal oxidation‐induced LCB of PEB more or less retarded the development of phase separation and once it reached a certain level, the reduced chain diffusion even arrested phase separation. The decrease of mass‐averaged molecular mass in H50 with high LCB level was ascribed to the reduced hydrodynamic volume. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011