Surface treatment mechanism of nano-SiO2 and the properties of PP/nano-SiO2 composite materials

The effects of different surface treatments of nano-SiO^sub 2^ on the microstructure, the particle distribution, interfacial adhesion, and the mechanical properties of PP/nano-SiO^sub 2^ composite materials were investigated. The mechanism of particle distribution arising from nano-SiO^sub 2^ surface treatment was analyzed. The results show that, by using only a small amount of nano-SiO^sub 2^, the strength and the modulus of the composite material can be increased effectively, and increased toughness at room temperature can result. Nano-SiO^sub 2^ was treated by A-1010 liquid phase first, then by PP solution, which acts as a big molecular obstructer layer of PP to assure that the distance between centers of mass is always larger than the van der Waals radius of particles, thus diminishing the tendency of agglomeration of SiO^sub 2^. This is beneficial to its distribution in PP and to its strong interfacial bonding with the PP matrix. The mechanical properties were superior to those of PP/nano-SiO^sub 2^ composite materials treated by A-1010 only.[PUBLICATION ABSTRACT]