摘要:
研究了“离位”增韧对RTM聚酰亚胺（PI-9731）树脂基复合材料力学性能的影响。结果表明： 当增韧剂的质量分数为15%时, 经粉末法和薄膜法“离位”增韧G827／PI-9731复合材料的室温层间剪切强度从增韧前的97.9MPa分别提高到108MPa和110MPa, 高温（288℃）层间剪切强度变化不大。G827／PI-9731复合材料经粉末法“离位”增韧后, Ⅰ型断裂能释放率从增韧前的310J/m2提高到410J/m2, Ⅱ型断裂能释放率从增韧前的590J/m2提高到939J/m2。而经过薄膜法“离位”增韧后, 其复合材料的Ⅰ型断裂能释放率提高到459J/m2, Ⅱ型断裂能释放率提高到1100J/m2。经电镜分析表明, 由于热塑性聚酰亚胺的引入, 在复合材料层间区域形成热固/热塑相反转结构, 在裂纹扩展的过程中, 包覆热塑性聚酰亚胺的PI-9731粒子发生明显取向和变形, 从而提高韧性。
Abstract:
The effect of ex-situ method on the mechanical properties and toughness of the RTMable carbon fiber (G827)／polyimide(PI-9731)composites was studied. The results show that the interlaminar shear strength of G827／PI-9731 composites toughened by the ex-situ methods with powder and film increases from 97.9MPa to 108MPa and 110MPa, respectively, when the thermoplastic PI mass fraction is 15% at room temperature. However, the interlaminar shear strength changes slightly at high temperature (288℃).The mode Ⅰ fracture toughness of G827／PI-9731 composites toughened with powder method is improved from 310J/m2 to 410J/m2. The Mode Ⅱ fracture toughness is improved from 590J/m2 to 939J/m2. However the mode Ⅰ fracture toughness of G827／PI-9731 composites toughened with film method increases to 459J/m2. The mode Ⅱ fracture toughness is improved to 1100J/m2. By SEM analysis, it is found that the toughness improvement results from the introduction of thermoplastic PI and the formation of the TP/TS phase inversion structure in the interlaminar regions, in which the PI-9731 particles wrapped by thermoplastic PI will be orientated and deformed in the process of crack extension.
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