微胶囊对微胶囊/环氧树脂复合材料增韧作用

Effects of microcapsules on toughening properties for microcapsule/epoxy composites

使用脲醛(Urea-formaldehyde)树脂-环氧树脂微胶囊(E-51)和三聚氰胺-尿素-甲醛共缩聚树脂(Melamine-urea-formaldehyde)-环氧树脂微胶囊(E-51)制备微胶囊/环氧树脂复合材料样品。对其力学性能进行了测试,并对复合材料的断面形貌进行了观察,研究了微胶囊对微胶囊/环氧树脂复合材料力学性能的影响。结果表明:随着微胶囊用量的增加,复合材料拉伸强度和弯曲强度有所降低;微胶囊质量分数小于2%时,复合材料断裂伸长率和断裂弯曲应变有所提高;大于2%时复合材料断裂伸长率和断裂弯曲应变下降。微胶囊对环氧树脂有增韧效果,微胶囊表面越粗糙,粒径越小,增韧效果越明显。在裂纹扩展区,大部分微胶囊破裂,裂纹终止区,大部分微胶囊剥离。

The microcapsules were synthesized by in-situ polymerization technology respectively with urea-formaldehyde resin（UF） or melamine-urea-formaldehyde co-condensed resin（MUF） as shell materials and epoxy resin（E-51） as core materials.A series of epoxy composite specimen were prepared using the microcapsules in order to study the effects of the microcapsules.Tensile and bending properties of the composite specimen were tested by universal tensile machine,and the fracture surface of composite materials was observed.The results show that the tensile strength and flexural strength of epoxy resin decrease with the increases of microcapsule amount.The elongation at break and fracture bending strain increase when the mass fraction of microcapsules is less than 2%,while decreases when the mass fraction of microcapsules is more than 2%.The microcapsules have a significant toughening effect on the epoxy resin.The rougher microcapsule surface and the smaller particle size are,the more ductile the composite is.The microcapsules likely rupture in the crack propagation and the microcapsules likely strip in the crack terminal zone.