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Effect of viscosity ratio, rubber composition, and peroxide/coagent treatment in PP/EPR blends
Author(s) -
Kim B. K.,
Do I. H.
Publication year - 1996
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/(sici)1097-4628(19960718)61:3<439::aid-app6>3.0.co;2-j
Subject(s) - spherulite (polymer physics) , crystallinity , materials science , electron paramagnetic resonance , polypropylene , izod impact strength test , ethylene propylene rubber , peroxide , crystallization , organic peroxide , copolymer , viscosity , composite material , polymer chemistry , ultimate tensile strength , polymer , chemistry , organic chemistry , physics , nuclear magnetic resonance
Effect of Viscosity ratio (ηEPR/ηPP), propylene (C 3 ) content of (ethylene‐propylene copolymer (EPR)), and peroxide/coagent treatment on polypropylene (PP)/EPR (80/20 by weight) melt blends were studied in terms of morphological, rheological, thermal, and mechanical properties. As the viscosity ratio increases from approximately 0.8 to 1.2, domain size increased (submicron‐1.5 μm), and the degree of supercooling (Δ T ) for crystallization increased (37.4–47.8°C) due to the decreased crystallization temperature ( T cc , 122.2–110.8°C). This resulted in larger spherulite size and increased hardness, modulus, and yield strength. With high C 3 EPR, total crystallinity (Δ H f ) of PP decreased, together with the mechanical properties, except the impact strength. With peroxide/coagent treatment, the spherulite size significantly decreased. The notched Izod impact strength decreased with increasing viscosity ratio, but significantly increased with high C 3 EPR and with peroxide/coagent treatments. The results were interpreted in terms of domain size and shape, chemical affinity between PP and EPR, copolymer formation, and main chain scission of PP. © 1996 John Wiley & Sons, Inc.