碳纤维缠绕复合材料NOL环的吸湿过程与性能关系

以碳纤维缠绕复合材料NOL环为研究对象，建立了一种研究碳纤维缠绕复合材料的壳体或压力容器在存贮和使用过程中湿热性能的加速老化方法。将复合材料NOL环分别浸泡在35℃、55℃、65℃和75℃蒸馏水中，研究其吸湿特性、动态力学性能以及静态力学性能的变化。结果表明，根据NOL环的吸湿特性，其吸湿过程可分为3个阶段：固有自由体积控制扩散吸湿阶段；分子链松弛控制吸湿阶段；界面破坏及裂纹扩展控制吸湿阶段。当湿含量达到1wt%左右时，复合材料进入界面破坏吸湿阶段，性能明显下降，剪切强度和弯曲强度保留率约为75%和67%，Tg下降了20℃。该结果可为碳纤维缠绕复合材料壳体或压力容器的存贮寿命的预测与评价提供重要依据。

Relationship between the moisture absorption and properties of carbon fiber filament-wound NOL rings

An accelerated aging method to characterize the hygrothermal properties of carbon fiber (CF) filament-wound composite pressure vessels in storage and service process was presented based on filament-wound composite NOL rings. The hygrothermal aging behavior of the CF/epoxy NOL rings in distilled water at 35℃，55℃，65℃ and 75℃ was analyzed in terms of the absorption characteristics，static and dynamic mechanical properties. The CF/epoxy NOL rings display a three-stage absorption process，which is controlled in turn by diffusion in free volume，molecular relaxation and interface degradation. When the moisture content reaches about 1wt%，the ring shear strength and flexural strength decrease to 75% and 67%；meanwhile，the Tg decreases by 20℃. The results providea good basis for the prediction and estimation of the storage life of carbon fiber filament-wound composite pressure vessels.