橡胶核壳纳米颗粒增韧环氧树脂/酸酐体系的制备及其性能

Preparation and its properties of rubber core-shell nanoparticle toughened epoxy resin/anhydride system

针对拉挤成型高强度、高韧性环氧树脂基体的应用需求,采用以柔性聚丁二烯(PB)为核、聚甲基丙烯酸甲酯(PMMA)为壳的橡胶核壳纳米颗粒增韧环氧树脂。采用红外光谱、示差扫描量热分析、粘度、硬度及力学性能测试研究了增韧剂含量对树脂的固化过程及性能的影响以及环氧树脂基体与核壳纳米颗粒之间的相互作用,并采用扫描电镜(SEM)观察了拉伸试样断面微观形貌。结果表明:增韧剂对环氧树脂的固化反应没有影响,使玻璃化转变温度略有降低。增韧剂的质量分数为8%时,树脂浇铸体的增韧效果最佳,拉伸强度、断裂伸长率、冲击强度分别达到了74.08 MPa、4.55%、39.6 kJ/m~2,与纯环氧树脂相比分别提高了3.7%、53.7%、23.8%。SEM分析表明其增韧机理主要是纳米颗粒诱导应力集中,形成塑性空洞和变形,吸收大量的能量,抑制裂纹的发展,从而提高了材料的韧性。

In order to meet the application requirements of epoxy resin matrix with high strength and high toughness for pultruding,the rubber core-shell nanoparticles with flexible polybutadiene(PB)as core and polymethyl methacrylate(PMMA)as shell were used to toughen epoxy resin. The effects of the oughening agent content on the curing process and properties of the resin,as well as the interaction between the epoxy resin matrix and core-shell nanoparticles,were investigated using infrared spectroscopy,differential scanning calorimetry and testings of viscosity,hardness,and mechanical properties. The section morphology of tensile specimens was observed by scanning electron microscopy(SEM). The results showed that the toughening agent had no effect on the curing reaction of epoxy resin,and the glass transition temperature was decreased slightly. when the the mass fraction of the toughening agent was 8%,the toughening effect of the resin castables was the best. The tensile strength,elongation at break and impact strength reached 74.08 MPa,4.55% and 39.6 kJ/m2,respectively,which increased by 3.7%,53.7% and 23.8% compared with the pure epoxy resin. The SEM analysis showed that the main toughening mechanism was that the stress concentration was induced by the nanoparticles,forming plastic cavity and deformation,absorbing a lot of energy,suppressing the development of cracks,and thus improving the toughness of the material.