Study on poly(propylene)/ammonium polyphosphate composites modified by ethylene-1-octene copolymer grafted with glycidyl methacrylate

The compatibilization effect of ethylene-1-octene copolymer grafted with glycidyl methacrylate (POE-g-GMA) as an interface compatibilizer on the mechanical and combustion properties, and the morphology and structures of the cross sections of ammonium polyphosphate (APP)-filled poly(propylene) (PP) were investigated by thermogravimetry, dynamic mechanical analysis, and differential scanning calorimetry. The results indicated that the toughness of the PP/APP composites increased rapidly with adding POE-g-GMA; the dynamic mechanical spectra revealed that the increase of the toughness was closely related to the peaks of loss modulus (E) and mechanical loss (tan 5). The improvement of the dispersion of APP in the PP matrix was attributed to the addition of POE-g-GMA; it was found that the interfacial adhesion between the filler and matrix was enhanced when the grafting material was added to the composites. Under such circumstances, the ratio of char formation was increased when the PP composites were heated, although the content of flame retardant was not changed, so the flame retardance of the material was improved. The addition of POE-g-GMA increased the rate of crystallization. At the same time, the degree of crystallinity and the temperature at the beginning of crystallization were decreased, although exerting little influence on the melt behavior of the crystallization of the composites. (C) 2004 Wiley Periodicals, Inc.