聚醚砜增韧环氧树脂的力学性能及固化体系相分离

环氧树脂是高性能纤维增强复合材料中应用最广泛的热固性基体树脂之一,但是环氧树脂固化后交联密度高、内应力大、质脆、耐疲劳性与耐冲击性差等不足在很大程度上限制了它在一些高技术领域的应用。利用聚醚砜(PES)对环氧树脂(E51)进行增韧改性,利用热熔法制备不同PES含量的PES/E51体系,加入E100固化剂制备成浇注体。利用热台偏光显微镜观察PES在E51中的溶解情况,采用拉伸、冲击等力学性能评价不同PES含量PES/E51/DETD浇注体的力学性能,利用热台偏光显微镜研究体系的相分离过程,采用扫描电子显微镜(SEM)观察固化后树脂体系的相分离情况。结果表明,PES与E51树脂具有良好的相容性,PES的加入可有效改善固化树脂的力学性能,相对于未固化环氧树脂,加入15wt%PES的浇注体拉伸强度和冲击强度分别提高了1.3倍和2倍,并且浇注体固化过程中出现相分离现象,15wt%PES的浇注体出现双连续相结构,使得力学性能表现出最优化。

MECHANICAL PROPERTIES AND PHASE SEPARATION OF EPOXY RESIN TOUGHENED BY POLYETHER SULFONE

Epoxy resin had been widely used in light industry,construction,machinery,aerospace,etc.But after curing,there were some disadvantages such as high crosslink density,excessive internal stress,crisp,poor fatigue resistance and impact resistance.Those shortcomings limite its application in a number of high-tech fields.In this paper,polyether sulfone (PES) was used to toughen epoxy resin.Different proportions of PES/E51 system were prepared by hot melt.Hot stage microscope,SEM and mechanical tests were applied to investigate morphologies and structures of E51 modified by PES,and also to evaluate fracture surface,phase separation,strength and toughness of castings.The results show that PES can dissolve in the E51 by hot melt in the absence of solvent.At PES content of 15wt％,the tensile strength and impact strength of castings increased by 130％ and 200％.Phase separation occurred when the castings were cured.PES formed a semi-continuous or continuous phase structure in the E51.When PES was 15wt％,bicontinuous structure appeared in the castings.