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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97.9 MPa分别提高到108 MPa和110 MPa,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310 J/m2提高到410 J/m2,Ⅱ型断裂能释放率从增韧前的590 J/m2提高到939 J/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459 J/m2,Ⅱ型断裂能释放率提高到1100 J/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。
The effect of “out of position” toughening on the mechanical properties of RTM polyimide (PI-9731) resin matrix composites was investigated. The results show that when the mass fraction of toughening agent is 15%, the interlaminar shear strength of G827 / PI-9731 toughened by both powder method and film method is higher than that before toughening at 97.9 MPa Respectively, to 108 MPa and 110 MPa, respectively. There was no significant change in interlaminar shear strength at high temperature (288 ℃). After the G827 / PI-9731 composite was toughened by the powder method, the release rate of type Ⅰ fracture increased from 310 J / m2 before the toughening to 410 J / m2, and the release rate of type Ⅱ fracture increased from Pre-tough 590 J / m2 increased to 939 J / m2. After the thin film method, “release” toughening, the I type fracture energy release rate of the composites increased to 459 J / m2, and the release rate of Type II fracture increased to 1100 J / m2. Electron microscopy analysis shows that due to the introduction of thermoplastic polyimide, the thermoset / thermoplastic phase reversal structure is formed in the interlayer region of the composite material. During the crack propagation, the PI-9731 particles coated with the thermoplastic polyimide Obvious orientation and deformation, thereby enhancing toughness.