Reactive Extrusion of PP for Long Chain Branching
Sung Chul Kim
Center for Advanced Functional Polymers, Korea Advanced Institute of Science and Technology
Korea

Keywords: branching, PP-g-MA, diamine

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One of post-reactor modifications of PP for long chain branching is reactive extrusion of randomly functionalized PP with polyfunctional monomers. In this study, reactive melt processing of maleated polypropylene (PP-g-MA) with hexamethylene diamine (HMDA), and poly(propylene glycol)-bis-(2-propylamine) (Jeffamine D-400) was carried out. Three kinds of PP-g-MA having different maleic anhydride content of respectively 0.2, 0.5, 1.0 wt% were used. FTIR spectra show that branches and crosslinks were formed through the formation of amide and imide linkages between maleic anhydride group and diamine, and the reactivity of HMDA to maleic anhydride group is higher than that of Jeffamine D-400. Molecular weight of resulting polymer was increased with the increasing amount of diamine initially added, and some gels are formed at high diamine content. For PP-g-MA with low maleic anhydride content, increases in storage modulus and shear viscosities of reacted polymers were not observed, but there were considerable increases, when PP-g-MA having high maleic anhydride content reacted with HMDA.