Abstract Given the advantages of polyethyleneimine (PEI) for interface modification of carbon fiber reinforced polyamide 66 composite (CF/PA66), an effective method was developed to fabricate CNT@PEI-CF. The XPS results confirmed CNT@PEI-CF was covered with a double grafted layer. Interface stability investigated showed thermal stability (under injection molding temperature, about 270 °C) and structural stability of CNT@PEI-CF/PA66 interface were both improved, but PA66 crystallization behavior affected by CNT@PEI-CF was identical with that of pure PA66. The contact angle tests exhibited that its compatibility with PA66 was also enhanced. Its interfacial shear strength, composite tensile strength and elastic modulus increased by 64.74%, 27.58% and 22.68% compared with that of untreated-CFs and composite, respectively. These best mechanical properties were ascribed to the formation of “fish-scale” layers on pull-out fibers resulted from CNT@PEI-CF modification. It could be concluded that CNT@PEI-CF would not only enhance its composite mechanical properties, but also exhibit much fiber pull-out and avoid the catastrophic failure for CNT@PEI-CF/PA66 composites. This CF surface modification study would be beneficial to expand application of thermoplastic composite with reusability.

中文翻译：

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双接枝界面层对碳纤维增强聚酰胺66复合材料性能的影响

摘要 鉴于聚乙烯亚胺（PEI）在碳纤维增强聚酰胺66复合材料（CF/PA66）界面改性方面的优势，开发了一种制备CNT@PEI-CF的有效方法。XPS 结果证实 CNT@PEI-CF 被双接枝层覆盖。界面稳定性研究表明，CNT@PEI-CF/PA66 界面的热稳定性（注射成型温度下，约 270°C）和结构稳定性均得到改善，但受 CNT@PEI-CF 影响的 PA66 结晶行为与纯PA66。接触角测试表明其与 PA66 的兼容性也得到了增强。与未经处理的CFs和复合材料相比，其界面剪切强度、复合材料拉伸强度和弹性模量分别提高了64.74%、27.58%和22.68%。这些最佳机械性能归因于由 CNT@PEI-CF 改性在拉出纤维上形成“鱼鳞”层。可以得出结论，CNT@PEI-CF 不仅可以增强其复合材料的机械性能，而且还表现出大量的纤维拉出并避免了 CNT@PEI-CF/PA66 复合材料的灾难性失效。该CF表面改性研究将有利于扩大具有可重复使用性的热塑性复合材料的应用。