This paper addresses the characterisation of the mode I interlaminar fracture toughness of a carbon fibre/epoxy composite material, toughened with thermoplastic particles in the ply interlayers. The characterisation is undertaken at −55 °C, 19 °C, and 90 °C, on both dry and fully moisture saturated coupons. Fractographic observations of the delamination surfaces allows identification of the failure mechanisms. The mode I propagation fracture toughness tested at wet/90 °C exhibits a 176% increase compared to the dry/19 °C specimens, due to enhanced plastic deformation of the interlayers and more prominent fibre bridging. Moisture-saturated coupons tested at −55 °C suffered a 57% reduction of mode I fracture toughness compared to those under dry/19 °C conditions. This is due to the dis-bond and consequent plucking of the thermoplastic particles from the surrounding matrix. This observation points to the fact that wet/cold conditions may represent the worst-case scenario for the interlaminar fracture performance of composite systems toughened with thermoplastic interleaves.

本文探讨了碳纤维/环氧树脂复合材料的模式I层间断裂韧性的表征，该层在层间夹层中被热塑性颗粒所增强。表征是在−55°C，19°C和90°C的干燥和完全湿润的试样块上进行的。分层表面的分形观察可以识别破坏机理。在湿态/ 90°C下测试的I型传播断裂韧性比干态/ 19°C样品高176％，这是由于中间层塑性变形增强和纤维桥接更加突出。与在干燥/ 19°C条件下相比，在-55°C下测试的饱和水分试样的I型断裂韧性降低了57％。这是由于热塑性颗粒从周围基质上脱粘并因此拔出。该观察结果表明，湿/冷条件可能代表了用热塑性衬垫增强的复合材料系统的层间断裂性能的最坏情况。