三嵌段聚丙烯酸酯聚合物共聚组成对环氧树脂增韧效果的影响

Effect of Copolymerization Composition of Triblock Polyacrylates on Toughening Effect of Epoxy Resin

利用电子转移再生催化剂原子转移自由基聚合(ARGET-ATRP)合成了不同甲基丙烯酸甲酯(MMA)含量的三嵌段弹性体——聚甲基丙烯酸甲酯-b-聚丙烯酸丁酯-b-聚甲基丙烯酸甲酯(PMBM),并对环氧树脂E-51进行增韧。力学性能测试表明,当MMA含量为40%时增韧效果最好,冲击强度和平面应变断裂韧度(K_(IC))相对纯环氧树脂分别提高88%和94%,拉伸性能基本维持不变。扫描电子显微镜分析表明,含有PMBM增韧的环氧树脂固化物断裂面出现70~170 nm左右的孔洞且断裂表面粗糙,表现出韧性断裂的特征。当MMA含量为40%时,断裂面的孔洞较小,仅为127 nm,且孔洞密度最高。动态力学性能分析表明,当MMA含量为40%时,三嵌段弹性体的加入使得环氧固化物的玻璃化转变温度略有下降。

Triblock elastomer poly(methyl methacrylate-b-butyl acrylate-b-methyl methacrylate)(PMBM)with different contents of methyl methacrylate(MMA)was prepared by atom transfer radical polymerization(ARGET-ATRP)and used as tougheners for epoxy resin E-51.Mechanical properties tests show that when the MMA content is 40%,the toughening effect is best.The impact strength and fracture toughness(KIC)are increased by 88%and 94%,respectively,compared to pure epoxy resin.Tensile properties remain constant.Scanning electron microscopy(SEM)analysis show the fracture surface of the cured epoxy resin containing PMBM has pores of about 70~170 nm and the fracture surface is rough.It exhibits the characteristics of ductile fracture.When the MMA content is 40%,the holes in the fracture surface are as small as 127 nm,and the hole density is the highest in all.Dynamic mechanical property analysis show that when the MMA content is 40%,the addition of the triblock elastomer causes a slight decrease in the glass transition temperature of the cured epoxy resin.