Synthesis and Thermal Behavior of Silica-graft-Polypropylene Nanocomposite

摘要

The silica graft Poly(propylene)(PP) nanocomposites are successfully synthesized and their thermal properties are studied. The silica-graft-PP nanocomposites are prepared by radical grafting copolymerization of modified silica, styrene, and maleic anhydride (MAH) in PP/xylene solution. The Differential Scanning Calorimetry (DSC) results show that the melting peak and the crystalline temperature shift to higher with the increase of silica content due to the remarkable heterogeneous nucleation effect of nanoparticles in PP matrix. The thermal degradation behavior of silica graft PP nanocomposites was investigated by using non-isothermal thermogravimetric analysis (TGA). The results indicate that the thermal stability was significantly improved with the increasing of grafted silica. The activation energy (Ea) of silica/PP nanocomposites, which is evaluated by using the Freeman-Carroll method, is large than that of neat PP and increases with the silica content. The reason for this enhancement may attribute to the physical-chemical adsorption of the volatile degradation products on the nanoparticles which delays the volatilisation of the products generated during decomposition, and the strong interaction between nanoparticles and polypropylene chains, which will largely weaken the breakage of polypropylene backbone chains.