Degradation testing of nylon 6-based carbon fiber-reinforced thermoplastic (CFRTP) was performed by exposure to hot steam in a closed vessel. The degraded structure was investigated to understand the degradation mechanism. Aging-induced micro-cracking in the nylon 6 matrix of CFRTP indicated that internal stress was generated by changes in its local density, along with a decrease in the molecular weight due to hydrolysis. Aging process of nylon 6 increased the free volume hole size in the amorphous part and also induced crystallization, suggesting that the density of the amorphous part decreases with increasing crystallinity in the matrix. Therefore, the degradation mechanism of the CFRTP was proposed to begin with a change in the local density of nylon 6 owing to crystallization, followed by water infiltration and hydrolysis of the matrix. Stress due to density changes combined with reduced molecular weight forms micro-cracks, decreasing the mechanical strength of CFRTP.

尼龙6基碳纤维增强热塑性塑料（CFRTP）的降解测试是通过在密闭容器中暴露于热蒸汽中进行的。对降解结构进行了研究，以了解其降解机理。CFRTP尼龙6基体中的老化诱发的微裂纹表明，内部应力是由其局部密度的变化以及水解引起的分子量降低而产生的。尼龙6的老化过程增加了非晶部分中的自由体积孔尺寸，并且还引起了结晶，这表明非晶部分的密度随着基质中结晶度的增加而降低。因此，提出了CFRTP的降解机理，其开始是由于结晶引起尼龙6局部密度的变化，然后是水的渗透和基质的水解。