短纤维对橡胶发泡复合材料增强机理的细观分析

分别制备未增强的橡胶发泡体、未处理短纤维增强的橡胶发泡体和预处理短纤维增强的橡胶发泡体,考察气体泡孔和短纤维在橡胶发泡复合体中的微观形态,细观分析短纤维对橡胶发泡复合材料拉伸行为和压缩行为过程各阶段的增强机理。结果表明:气体泡孔在3种发泡复合材料基体中分布均匀,模压工艺使得短纤维在基体中呈现为平面分布,未处理短纤维周围有气泡包围,而预处理短纤维与橡胶间粘合良好;短纤维能有效地提高发泡复合材料在初始阶段的拉伸模量和100%定伸应力,特别是预处理短纤维表面与橡胶之间具有良好的粘合,有利于传递应力,限制橡胶基体的变形,而对拉伸强度却影响不大。在压缩弹性阶段,由于主要承载的泡壁中纤维呈平面取向,短纤维对压缩模量影响不大,但能有效地限制橡胶发泡复合材料在后屈曲阶段的压缩变形,提高其在高应变下的压缩强度,预处理短纤维增强效果明显高于未处理短纤维。

Study on reinforcement mechanism of short fiber/rubber foam composite

The rubber foam composites without short fiber (RF),reinforced by untreated short fiber (USRF) or pretreated fiber (TSRF) were prepared by mold foam technique.The morphology of cell and short fiber in each composite and the reinforcement mechanism of short fiber in the composite during tensile and compression processes were investigated.The results showed that the cells distributed uniformly in the matrixes of all three composites;the compression molding technique made the short fiber distribute planaryly in the matrix;the short fiber could improve the tensile modulus of composite at the first stage and the modulus at 100% elongation,and had little effect on tensile strength;the untreated fiber was surrounded with many cells,but the pretreated fiber bonded well to the rubber matrix,which was beneficial to transfer the stress and confine the deformation in rubber matrix;the short fibers,whether pretreated or not,had little effect on the compressive modulus at the compressive elasticity stage because they were planaryly oriented in the cell walls which were the main loading elements;and the short fiber,especially the pretreated short fiber greatly restricted the distortion at the high compressive strain stage resulting in higher compressive strength.