Polypropylene/Silica Nanocomposites Prepared by In-Situ Melt Ultrasonication

A novel process using ultrasonic irradiation to enhance nanosilica dispersion in polypropylene-based nano-composites has been proposed and investigated. The nanocomposites were isotactic polypropylene reinforced with silica nanoparticles at 3 wt% loading level. Ultrasonic processing in the melt state is an effective method for improving nanosilica dispersion. The effectiveness of the proposed ultrasonic processing technique on polypropylene nanocomposites was evaluated by XRD and transmission electron microscopy (TEM). Poly(propylene-g-maleic anhydride) copolymer (PP-g-MAH) containing 5 wt% maleic anhydride content was added to nanocomposites at 0.5 wt% concentration based on silica content. PP-g-MAH plays an important role in nanosilica dispersion in polymer matrix and interface interaction. The reaction of maleic anhydride groups with the hydroxyl groups on the surface of nanosilica was characterized by FTIR spectrum. The final nanocomposites result in a further enhancement of mechanical properties because of silica agglomerate reduction and improving interface combination, even loading level being much lower than that of ordinary fillers in conventional composites. POLYM. COMPOS., 30:835-840, 2009. (C) 2009 Society of Plastics Engineers