LPA对UPR收缩率和力学性能的影响

针对不饱和聚酯树脂(UPR,Unsaturated Polyester Resin)收缩率高和脆性大的缺点,研究了加入两种低轮廓添加剂(LPA,Low Profile Additives)--聚醋酸乙烯酯类的LPA-4016和聚苯乙烯类的LPA-7310--对UPR浇注体的体积收缩率和力学性能的影响,分析了两种体系的相结构转变及不同的低收缩控制机理,LPA-4016主要是通过在LPA颗粒相周围形成许多均匀分散的空隙来抵消树脂的固化收缩;而LPA-7310则主要是通过自身充分膨胀来抵消树脂的固化收缩.结果表明,LPA-4016对UPR的收缩控制存在一个较合适的加入量范围,且与LPA-7310相比,其可改善UPR的脆性,提高冲击强度,但两者都会降低UPR的拉伸强度.

Effect of low profile additives on the shrinkage and mechanical properties of unsaturated polyester

In order to reduce the high shrinkage ratio and great brittleness of UPR(unsaturated polyester resin),two kinds of LPA(low profile additives),which are LPA-4016 of polyvinyl acetate and LPA-7301 of polystyrene,are added into UPR cast separately.The effects of LPA on the shrinkage rate and mechanical properties of UPR cast are studied,and then the phase structure transitions of these two systems and their different control mechanisms of low shrinkage rate are analyzed.For LPA-4016,it is by formatting amounts of uniform and disperse voids around the LPA phase to buck the shrinkage during resin cure;while for LPA-7310,this is realized primarily by the sufficient expansion of LPA itself.The results show that there exists an optimal quantity for LPA-4016 to reduce shrinkage rate of UPR,and it can improve the brittleness of UPR and increase its impact strength in contrast with LPA-7310.But both of them tend to reduce the tensile strength of UPR.