复合材料用环氧树脂的韧化(五)增靱机理的探讨

本文工作研究了复合材料用环氧树脂的韧化。该体系由无规羧基丁腈橡胶,双酚A型环氧树脂,2-乙基-4-甲基咪唑组成。无规羧基丁腈橡胶对环氧树脂的增韧效果以及用增韧环氧树脂作基体材料对复合材料性能的影响已作报导1,2,3]。本文报导无规羧基丁腈橡胶增韧环氧浇注体在应力下的形变特性及裂缝扩展特征。主要阐述橡胶增韧环氧浇注体受拉应力作用时,产生的两个形变过程——裂纹化与剪切变形,并根据双悬臂梁劈裂试件的断裂面形态,讨论了裂缝亚临界扩展区。

TOUGHENING EPOXY RESIN MATRIX FOR FIBER REINFORCED COMPOSITES——Ⅴ:TOUGHENING MECHANISM

Toughening of an epoxy resin system for glass and carbon fiber composites is investigated.The system consists of butadiene-acrylonitrile rubber with random carboxyl groups (CTBNX),epoxy resin of diglycibyl ether of bisphenol A (DGEBA) and 2-ethyl-4-mnthy limidazol.The authors' previous studies1,2,3] showed the following points:(1) A toughened epoxy resin can be prepared with CTBNX or GTBNX-bisphenol A to form two-phase system.The toughened epoxy resin exhibits significant improvements over the un modified ones by 2 to 10 times in impact strength,by 0.5 to 11.5 times in modulus of toughness(area under the stress-strain curve under tension) and by 1 to 4 times in fracture surface energy.(2) When the toughened epoxy resin is used as matrix for glass fiber composites,it improve longitudinal and transverse impact strength, fracture surface energy, candidate stress intensity factor KQ in unidirectional laminates and other resin-dependent mechanical properties.