Polystyrene-matrix Micro-and Nano-composites Modified By MA-g-SEBS

PS/maleic anhydride grafted styrene-(ethylene-co-butyl-ene)-styrene (MA-g-SEBS) blend, PS/micro-sized glass bead (GB) and PS/nano-sized SiO2 composites with MA-g-SEBS as toughener and compatilizer, were prepared by melt compounding and compression molding. Their morphological structure, dynamic mechanical properties, Izod notched impact and tensile strength were systematically investigated. The results and conclusions were received as followings: (1) PS/MA-g-SEBS blends exhibit typical ductile fracture feature with silk-net morphology, whilst pristine PS is brittle with smooth impact fractured surface. The addition of MA-g-SEBS decreases the modulus of PS, and has almost not effect on Tg of PS. With increasing the MA-g-SEBS content, the tensile and Izod notched impact strength of blends increase. (2) As the same as PS/MA-g-SEBS blends, PS/MA-g-SEBS/GB composites showed the ductile fracture feature. Due to the synergistic toughening effect of GB and MA-g-SEBS, GB particles have obvious reinforcement and toughening to PS matrix. Compared with PS, the addition of 2.5 and 5wt% MA-g-SEBS in PS/MA-g-SEBS/GB composites with 20% GB increases 37.61% and 108.55% in their Izod notched impact strength respectively, and increases 29.59% and 12.54% in their tensile strength respectively. (3) PS/MA-g-SEBS/nano-SiO2 composites exhibit typical ductile fracture feature with the morphological structure of silk-like networks although there exists nano-SiO2 agglomeration in matrix. Due to the synergistic toughening effect of MA-g-SEBS and nano-SiO2, nano-SiO2 particles show the reinforcement and toughening to PS matrix. Compared with PS, the addition of 2.5 and 5wt% MA-g-SEBS in PS/MA-g-SEBS/ nano-SiO2 composites with 5% nano-SiO2 increases 29.91% and 52.14% in their Izod notched impact strength respectively, and increases 10.04% and 31.38% in their tensile strength respectively.