国内精品国产三级国产在线专_欧美日韩在线播放一区二区_成人xxxx视频_欧美激情视频一区_色女人综合av_久久久亚洲影院_久久久久久九九_成人免费网站在线_日韩美女毛茸茸_狠狠干一区二区

  A series of submicrometer-sized polybutadiene (PB) rubber particles with different diameters ranging from 100 to 450 nm were prepared via an emulsion polymerization. Subsequently, core.shell polybutadiene-graf t-polystyrene (PB-g-PS) particles were synthesized using a redox initiator system (cumene hydroperoxide and ferrous sulfate) by an emulsion grafting polymerization. Then the submicrometer sized PB-g-PS impact modifiers were utilized to toughen polystyrene (PS) by blending PS and high-impact polystyrene. From measuring mechanical properties, it was found that the notched impact strength of toughened PS was significantly influenced by core.shell PB-g-PS particle size. When the rubber particle size was above 300 nm, the notched impact strength was 208 J/m, nearly 2 times than that of toughened PS with particle size 100 nm. Moreover, the stress whitening zones were observed by transmission electron microscopy, and the result showed that multiple crazing is its dominative toughening mechanism.