聚酰亚胺改性耐高温透波邻苯二甲腈复合材料制备

Preparation of High-Temperature Resistant Wave-Transmitting Phthalonitrile Based Composites Modified by Polyimide

针对耐高温透波邻苯二甲腈树脂韧性低、抗冲击性能差的缺点,通过热固性邻苯二甲腈与热塑性聚酰亚胺共混形成预聚物,经高温固化及后热处理制备了聚酰亚胺/邻苯二甲腈共混固化物及石英纤维增强复合材料,并研究了其工艺性能、热性能、介电性能及力学性能。结果表明,该热塑性聚酰亚胺与热固性邻苯二甲腈树脂相容,增韧组分的引入改善了原材料的工艺性能,共混后在不降低原树脂及复合材料优异介电性能的同时实现了复合材料的增韧增强,质量失重5%时热降解温度Td5由503℃提高到550℃,复合材料玻璃化转变温度由461℃提高到491℃,室温弯曲强度提高了约16.27%,层间剪切强度提高了约18%。冲击后压缩强度由160 MPa提高到194 MPa。

The poor destructive resistance,low toughness and poor impact resistance of thermosetting phthalonitrile resin has limited the development and further application of it.Focusing on these shortages,prepolymer was blended by thermosetting phthalonitrile resin and thermoplastic polyimide,and glass fiber reinforced polyimide/phthalonitrile blend composites were prepared by high temperature curing and post heat treatment.Technological properties,thermal properties and mechanical properties had been studied.The results show that the thermosetting phthalonitrile resin is compatible with the thermoplastic polyimide.The phthalonitrile resin is modified by blending with the thermoplastic polyimide.The toughening and strengthening of the composites are realized without reducing the excellent dielectric properties and processing properties.After the blending toughening modification,the thermal decomposition temperature of the composite(Td5)is increased from 503℃to 550℃,and the glass transition temperature of the composite is increased from 461℃to 491℃.The bending strength and interlaminar shear strength at room temperature are improved by around 16.27%and 18%respectively.In addition,the compression strength after impact(CAI)of composites is increased from 160 MPa to 194 MPa after the blending modification.