Dynamic‐mechanical and thermal characterization of polypropylene/ethylene–octene copolymer blend

Abstract

AbstractPolypropylene/Ethylene–Octene copolymer (PP/EOC) blends were prepared by melt blending technique followed by compression molding. The effect of addition of EOC on the mechanical behavior of the PP matrix was investigated. Tensile and flexural strengths decreased with the incorporation of EOC. However, the impact strength of the matrix polymer increased in all the blend systems. The blends prepared at 30% EOC content showed an increase in the impact strength to the tune of 380% as compared with polypropylene (PP) matrix. The morphology of the fractured surfaces was investigated employing Scanning Electron Microscopy. SEM micrographs depicted the formation of biphase structure, wherein the EOC phases were homogeneously dispersed as small droplets within the PP matrix. WAXD patterns revealed that the α monoclinic form of isotactic PP does not show any significant change with the incorporation of EOC up to 70 wt %. DSC thermograms revealed a decrease in the melting temperature of the virgin matrix with the addition of EOC. The blend system at 50% EOC exhibited a broad crystallization exotherm at 75°C thus indicating multiple crystallization behavior primarily attributed to the difference in the nucleation process. Further DMA analysis showed presence of two different relaxation peaks corresponding to the Tg of EOC and PP matrix respectively, confirming the formation of a biphase structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007