Abstract One of the major concerns of carbon fiber-reinforced nylon 6 composites (CF/Nylon 6) is its sensitivity to environmental degradation, especially hygrothermal aging. In this study, neat nylon 6 plates and unidirectional CF/Nylon 6 laminates with different fiber orientations manufactured by hot compression method were subjected to water absorption tests by immersing them in 80 °C and 98 °C hot water for various time durations. The corresponding flexural mechanical properties, including the flexural modulus and flexural strength, of the as-prepared samples before and after water absorption were evaluated by using three-point bending tests. The effects of immersion time, fiber orientation, and water temperature on the flexural properties are discussed. Flexural cyclic tests were conducted to evaluate the stiffness degradation of neat nylon 6 and unidirectional CF/Nylon 6 laminates. Optical observation and scanning electron microscopy were used to observe the fracture behavior of unidirectional CF/Nylon 6 laminates before and after water absorption. Results indicated that the flexural modulus and strength of unidirectional CF/Nylon 6 laminates in different fiber orientations decreased by ≈ 8%–60% and ≈40%–60% after hot water immersion, which was mainly caused by the weakened matrix (the cleavage reaction of the main chain and plasticization of the matrix) and weakened interfacial properties (attack on the interface by hot water). The fracture behavior of 0° CF/Nylon 6 laminates after water immersion tended to be more ductile than those without hot water immersion.

中文翻译：

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热水对单向碳纤维增强尼龙6复合材料力学性能的影响

摘要 碳纤维增强尼龙 6 复合材料 (CF/Nylon 6) 的主要问题之一是其对环境降解的敏感性，尤其是湿热老化。在这项研究中，通过将它们浸入 80 °C 和 98 °C 的热水中不同时间，对通过热压法制造的具有不同纤维取向的纯尼龙 6 板和单向 CF/尼龙 6 层压板进行吸水测试。通过使用三点弯曲试验评估吸水前后所制备样品的相应弯曲力学性能，包括弯曲模量和弯曲强度。讨论了浸泡时间、纤维取向和水温对弯曲性能的影响。进行弯曲循环试验以评估纯尼龙 6 和单向 CF/尼龙 6 层压板的刚度退化。采用光学观察和扫描电镜观察单向CF/Nylon 6层压板吸水前后的断裂行为。结果表明，不同纤维取向的单向CF/Nylon 6层压板的弯曲模量和强度在热水浸泡后分别下降≈8%–60%和≈40%–60%，这主要是由于基体弱化（解理主链的反应和基体的塑化）和减弱的界面性能（热水对界面的攻击）。0°CF/Nylon 6 层压板在水浸泡后的断裂行为比没有热水浸泡的层压板更具延展性。