Constructing flame retardant silica nanoparticles through styrene maleic anhydride copolymer grafting for PC/ABS composites

Organic-inorganic hybrid particles have been prepared by grafting styrene maleic anhydride copolymer (SMA) onto reactive amino-modified silica nanoparticles. The SMA modified SiO2 (SMA-SiO2) was incorporated into polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) composites (4:1, wt%/wt%) with bisphenol A bis (diphenyl phosphate) (BDP) to simultaneously improve the mechanical properties and flame retardancy. The mechanical properties of the sample containing SMA-SiO2 are apparently improved compared with that of samples containing unmodified SiO2. It is found that SMA-SiO2 tends to distribute at the phase interface of PC/ABS, and therefore improves the compatibility between PC and ABS. Besides, the peak of heat release rate (PHRR) and the total smoke production (TSP) of the PC/ABS composites are decreased by the presence of SMA-SiO2. It is suggested that SMA-SiO2 can form a flame retarding shell at the phase interface to protect ABS. In summary, both the mechanical properties and flame retardancy of PC/ABS composites are significantly improved due to the selective distribution of SMA-SiO2.