Atomic force microscopy study on structure and properties of irradiation crafted silica particles in polypropylene-based nanocomposites

Nanosilica particles treated by irradiation grafting polymerization can eff ectively improve the strength and toughness of a thermoplastic polymer at a rather low filler content. A detailed investigation on the modified nanopa rticles in the absence and presence of a polypropylene matrix is carried ou t by using atomic force microscopy. The results indicate that the loosen ag glomerates of the untreated SiO2 became more compact due to the linkage bet ween the nanoparticles offered by the grafting polymer. In addition, the mo lecules of the polypropylene matrix are able to diffuse into the modified n anoparticle agglomerates during the melt processing. Entanglement between t he molecules of the grafting polymer and the matrix is thus available, whic h in turn facilitates a strong particle-matrix interfacial interaction. (C) 2001 John Wiley & Sons, Inc.