SYNERGETIC EFFECT OF PEROXIDE AND MODIFIER TO OBTAIN HIGH MELT STRENGTH POLYPROPYLENE

Abstract

The goal of this research was to increase the melt strength of different polypropylene matrices to make them suitable for processes like thermoforming, extrusion coating, blow molding etc. involving the extensional flows. The enhanced melt strength was achieved by branching and crosslinking the chains with the help of a monomer - peroxide system. The cross-links induce a strain-hardening behavior which was verified by dynamic frequency sweep tests. The flow behavior was tested with the help of a melt indexer. FTIR analysis justified the incorporation of monomer onto the polymer backbone. DSC analysis showed the shifting of peaks resulting from a structural change among the chains. Based on these observations, conclusions were drawn for optimum concentrations of the monomer and peroxide required to yield best possible crosslinking efficiency between the chains.