端羧基丁腈橡胶和双酚A增韧混合环氧树脂体系的研究

STUDIES ON AN INTERMINGLED EPOXY RESIN SYSTEM TOUGHENED BY CTBN AND BISPHENOL A

本文以2-乙基-4-甲基咪唑(简称2,4-咪唑)为固化剂,研究了端羧基丁腈橡胶(简称CTBN)和CTBN/双酚A改性的双官能环氧E-51和四官能环氧F-76混合体系的热-机械性能、微观形貌和声发射响应。结果表明:加入5份CTBN,对混合环氧树脂体系的增韧效果不明显。加入5份CTBN和24份双酚A,使体系的韧性增加。但CTBN加入的顺序不同,其微观结构和力学性能不同,增韧效果亦不同。

In this paper, the thermal and mechanical preperties, microscopic morphology and acoustic emission (A. E.) response of the intermingled epoxy resin system modified by CTBN and bisphenol A are investigated with 2-ethyl-4-methylimidaze as curing agent. The intermingled epoxy resin system consists of bifunctional epoxy resin E-51 and tetrafunctional epoxy resin F-76. The results are summarized as follows: 1. The system of adding 5 phr CTBN in the intermingled epoxy resin, cast resin B, is a two phase system, but the toughening effect is inappreciable. Its elastic modulus is reduced and its thermal property is significantly lowered. The system of adding 5 phr CTBN and 24 phr bisphenol A in the intermingled epoxy resin, cast resin C, is also a two phase system. But its toughness is enhanced appreciably and its tensile and flexural strength are increased. Its elastic modulus is also improved compared with that of cast resin B. 2. The stress whitening phenomena under tension of cast resin B and C is observed. A.E. experiments show that it is because rubbery particles initiate craze in cast resins. The main difference between cast resin B and C is that the A. E. signals of cast resin B appear intermittenly while those of cast resin C continuously. 3. For cast resin C, the microscopic morphology, mechanical properties and toughening effects depend on the processing of adding CTBN, In general, the larger the rubbery particles in cast resins, the higher the tensile modulus of specimens is. The toughness of specimens with small rubbery particles is slightly higher than those with large rubbery particles.