尼龙无纺布增韧RTM复合材料的湿热老化性能

采用尼龙无纺布(PNF)作为结构化增韧层,利用树脂传递模塑(RTM)工艺制备了PNF层间增韧改性的碳纤维增强环氧树脂基复合材料(U3160-PNF/3266),研究了U3160-PNF/3266复合材料的吸湿特性及湿热老化对其耐热性能的影响。结果表明:增韧前后复合材料具有相似的吸湿动力学特性,但在吸湿初期,U3160-PNF/3266复合材料具有更大的吸湿速率,达到饱和吸湿后,U3160-PNF/3266复合材料的饱和吸湿率约为0.96%,略大于非增韧复合材料U3160/3266的0.87%。随着湿热老化时间的增加,两种复合材料的玻璃化转变温度均逐渐降低,并随着吸湿率的饱和而趋于平稳,达到饱和吸湿后,U3160-PNF/3266和U3160/3266复合材料的玻璃化转变温度分别下降了约15%和14%。

Hygrothermal aging properties of RTM composites toughened by polyamide nonwoven fabric

The polyamide nonwoven fabric (PNF) was chosen as structural toughening layer, and carbon fiber reinforced epoxy composites toughened by interlaminar PNF (U3160-PNF/3266) were fabricated by resin transfer molding (RTM) process. The moisture absorption properties of U3160-PNF/3266 composites and the influence of hygrothermal aging on heat resistant performance of it were investigated. The results indicate that composites have similar moisture absorption dynamics characteristics before and after toughening. But the moisture absorption rate of U3160-PNF/3266 composites is much larger at the original moisture absorption. The saturated moisture absorption rate of U3160-PNF/3266 composites is 0.96%, which is a little greater than that of untoughened composites (U3160/3266) of 0.87%. The glass transition temperatures of the two composites both decrease with the increment of hygrothermal aging time, and are going to be stable as the moisture absorption rate saturate. Up to the saturated moisture absorption, the glass transition temperatures of U3160-PNF/3266 and U3160/3266 composites are reduced by approximately 15% and 14% respectively.