Improvement of impact properties of polypropylene by modification with very low‐density polyethylene

Very low‐density polyethylene (VLDPE) was compounded with polypropylene (PP) to improve its impact strength. VLDPE was modified by grafting 3‐(trimethoxysilyl) propyl methacrylate silane (MS) to VLDPE to prepare mVLDPE. PP was melt‐mixed either with VLDPE or mVLDPE together with Cloisite®20A (C20A). The composites exhibited a phase‐separated morphology, irrespective of whether the VLDPE had been modified with the silane compounds or not. Incorporation of C20A decreased the domain size of the dispersed phases of both PP/VLDPE and PP/mVLDPE blends. The tensile strength and elongation at break of PP/VLDPE and PP/mVLDPE were improved by the addition of C20A. In contrast, their impact strengths were reduced by the clay. However, the decrease in impact strength was less significant in PP/mVLDPE/C20A than in PP/VLDPE/C20A. The superior mechanical properties of PP/mVLDPE/C20A over PP/VLDPE/C20A were attributed to enhanced interfacial interactions originating from chemical reactions between silane residues on mVLDPE and the silanol groups of C20A. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011