超微细Al_2O_3增韧增强聚苯乙烯的研究

POLYSTYRENE TOUGHENED AND STRENGENED BY ULTRAFINE Al_2O_3 PARTICLES

通过室温填充本体聚合制备了聚苯乙烯／Ａｌ_２Ｏ_３复合材料。并通过力学性能测试证明半径小于０．５μｍ的超微细Ａｌ_２Ｏ_３粒子能增韧增强聚苯乙烯，且基体层的临界增韧厚度为０．１μｍ，而大于５μｍ的Ａｌ_２Ｏ_３对聚苯乙烯无增韧增强作用。扫描电镜照片显示超微细Ａｌ_２Ｏ_３均匀地分散在聚苯乙烯中而未发生团集。ＤＳＣ分析结果说明，超微细Ａｌ_２Ｏ_３的加入提高了聚苯乙烯的耐热性，并且预示聚苯乙烯和超微细Ａｌ_２Ｏ_３有化学结合。

In this paper, the polystyrene/Al_2O_3(PS/Al_2O_3) composites was prepared by filler-monomer bulk polymerization in room temperature .The effects of Al_2O_3 particles content and size on tensile strength and notched izod impact strength of PS were investigated. The results show that ultrafine Al_2O_3 perticle radius is below 0. 5 μm could toughen and strengen PS, the particle radius is above 5 μm counld not. It can be concluced that the smaller the particle radius is,the smaller the critical Al_2O_3 volume fraction is and the greater the tensile and impact strength. It is interesting to find that the critical matrix ligament thickness (Lc) of PS/Al_2O_3 composites is 0. 1 μm, the interface layer thickness (Li) is 0. 012 μm, and when matrix ligament thickness L>Lc or L<2Li, PS is not toughened, when 2Li<L<Lc, PS is toughened.The SEM of PS/Al_2O_3 sample shows clearly that ultrafine Al_2O_3 particle are dispersed in PS matrix and don' t aggregate.The DSC curves indicate that there is chemical bonding between ultrafine Al_2O_3 and PS.