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Long chain branched impact copolymer of polypropylene: Microstructure and rheology

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Title Long chain branched impact copolymer of polypropylene: Microstructure and rheology
 
Creator CHIKHALIKAR, K
DESHPANDE, A
POL, H
DHOBLE, D
JHA, S
JADHAV, K
MAHAJAN, S
AHMAD, Z
KULKARNI, S
GUPTA, S
LELE, A
 
Subject MELT RADICAL REACTION
REACTIVE EXTRUSION
MOLECULAR-STRUCTURE
THERMORHEOLOGICAL BEHAVIOR
FLOW PROPERTIES
POLYMER MELTS
MONOMER
POLYETHYLENES
STRENGTH
TRIACRYLATE
 
Description A biphasic impact copolymer of polypropylene (ICP) was modified with peroxide by reactive extrusion process resulting in reduced melt flow index, improved melt strength, and higher die swell. The polymers were for the first time subjected to systematic rheological and microstructural characterization in an effort to understand their structure-property relations. In shear rheological tests, the modified ICP displayed higher flow activation energy, reduced values of loss tangent and nearly equal frequency dependence of storage and loss modulli. The modified ICP also showed strain hardening behaviour in uniaxial extensional rheology and higher crystallization temperature in differential scanning calorimetry (DSC). All these are definitive indications of the presence of long chain branches (LCB). Fitting the rheological data of modified ICPs with the eXtended Pom Pom (XPP) model indicated the presence of LCB on the higher molecular weight fraction in the polymer, a result which was corroborated with multi-detector high temperature gel permeation chromatography (HT-GPC). More importantly, the matrix and rubber phases of the ICP were separately characterized for presence of long chain branching by rheology, DSC and HT-GPC. The results indicate that while LCB existed in the matrix phase, microgels were present in both phases indicating that the reaction with peroxide occurred in both phases. POLYM. ENG. SCI., 55:1463-1474, 2015. (c) 2014 Society of Plastics Engineers
 
Publisher WILEY-BLACKWELL
 
Date 2016-01-14T10:45:44Z
2016-01-14T10:45:44Z
2015
 
Type Article
 
Identifier POLYMER ENGINEERING AND SCIENCE, 55(7)1463-1474
0032-3888
1548-2634
http://dx.doi.org/10.1002/pen.23993
http://dspace.library.iitb.ac.in/jspui/handle/100/17393
 
Language en