乙烯基酯树脂的微观结构及其力学性能研究

树脂的微观结构决定其力学性能 ,乙烯基酯树脂微观结构的一个重要特征就是凝胶粒子和两相结构的存在 .采用SEM、DSC研究了乙烯基酯树脂固化过程中凝胶粒子的形成过程及两相结构对固化放热的影响 ,结果表明 ,凝胶粒子在固化树脂中呈群状分布 ,每群凝胶粒子的最大尺寸为 2 0 μm左右 ,每群凝胶粒子由许多独立凝胶粒子组成 ;凝胶粒子的形成使树脂产生了两相结构 ,使树脂的恒温DSC残余放热呈双峰分布 ;树脂的固化条件影响其微观结构 .力学性能测试的结果表明树脂的固化条件影响其力学性能 ,低温固化树脂(80℃固化 )的后固化可以提高其拉伸强度和弯曲强度 ,对于高温固化树脂 (12 0℃固化 ) ,则出现相反的趋势 ,后固化降低了树脂的拉伸强度和弯曲强度 .

STUDIES ON THE MICRO-STRUCTURE AND MECHANICAL PROPERTIES OF CURED VINYL-ESTER RESIN

The microstructure in cured resins decides their mechanical properties.An important characteristics in cured vinyl-ester resin is micro-gels and bi-phase structure.The morphological structure of cured vinyl-ester resin and the formation of two-phase structures in vinyl-ester resin has been studied by using SEM and differential scanning calorimetry (DSC).The results demonstrated the existence of clusters of gel-particles with a size of about 20?μm,each cluster of gel-particles containing many gel-particles with coral-like structures.The formation of gel-particles resulted in two-phase structure characterized by the two peaks in the rescanned DSC thermographs of the resin.The cure conditions (temperatures,post-cure) affected microstructure in the cured resins.The results of mechanical properties showed that the cure conditions affected the mechanical properties.The post-cure for the sample isothermally cured at 80℃ increased the tensile strengths and flexural strengths.On the contrary,the post-cure for samples isothermally cured at 120℃ decreased the tensile strengths and flexural strengths.