With an increase in the use of carbon fiber composites in the aerospace and automobile industry a collateral issue of what to do with end-of-life carbon fiber composites has risen. In this study, we successfully developed a second-generation composite using a heterogenous mixture of thermoset and thermoplastic recycled carbon fiber composites (CFCs). The recovered vinyl ester and epoxy CFCs (thermosets) were characterized using thermogravimetric analysis. Adhesive performance was evaluated through double lap shear tests by melt-bonding a thermoplastic polyether ether ketone (PEEK) CFC to either the thermoset epoxy or vinyl ester CFC. The waste carbon fiber composites were also mechanically milled and classified through screening techniques. The resulting milled materials were used to form and produce composite panels through high temperature compression molding. The influence of particle size and platen temperature were evalauted through mechanical testing. Results indicate that melt-bonding with the vinyl ester/CFC exhibited significantly higher lap shear strength values than that between epoxy/CFC and PEEK. Findings also show that adding thermoset CFCs to the thermoplastic system (PEEK) enhanced the flexural properties of composites.

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中文翻译：

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用于第二代复合材料的非均质热固性/热塑性再生碳纤维复合材料

随着在航空航天和汽车工业中碳纤维复合材料的使用增加，如何处理使用寿命终止的碳纤维复合材料的附带问题也日益增多。在这项研究中，我们成功地使用热固性塑料和热塑性回收碳纤维复合材料（CFC）的异质混合物开发了第二代复合材料。使用热重分析法对回收的乙烯基酯和环氧CFC（热固型）进行了表征。通过将热塑性聚醚醚酮（PEEK）CFC熔融粘合到热固性环氧或乙烯基酯CFC上的双搭接剪切测试，评估粘合性能。废碳纤维复合材料也通过研磨技术进行机械研磨和分类。所得的研磨材料用于通过高温压缩成型来形成和生产复合板。通过机械测试避免了粒径和压板温度的影响。结果表明，与乙烯基酯/ CFC的熔融粘合表现出的搭接剪切强度值明显高于环氧/ CFC和PEEK之间的搭接剪切强度值。研究结果还表明，将热固性CFC添加到热塑性体系（PEEK）中可增强复合材料的弯曲性能。

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