| Related citation: | Ruonan Wang,Haihong Wu,Ziyue Guo,Chuntai Liu,Changyu Shen.Improving Strength of Carbon Fiber Grafted Carbon Nanotube Reinforced Thermoplastic Composites by 3D-Printed Molding[J].Journal of Harbin Institute Of Technology(New Series),2019,26(2):71-79.DOI:10.11916/j.issn.1005-9113.18099. |
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| Author Name | Affiliation | | Ruonan Wang | College of Mechanical Engineering, Henan University of Technology, Zhengzhou 450001, China | | Haihong Wu | College of Mechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China | | Ziyue Guo | School of Mathematics, Sun Yat-sen University, Zhuhai Campus, Zhuhai 519082, China | | Chuntai Liu | National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China | | Changyu Shen | National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China |
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| Abstract: |
| To improve the strength of carbon fiber (CF) reinforced Polycaprolactam (PA6) composites, controlled amounts of carbon nanotubes (CNTs) were grafted onto the surface of CF to prepare the hybrid reinforcement (HR). We used HR to fabricate laminate and H-sample to test the interfacial bonding strength (IBS) of the composites by means of a novel process called three-dimensional printed molding (3D-PM). By using the melt drop printing method, we measured the contact angles between PA6 and CF (without sizing) and between PA6 and HR. The IBS and the mechanical properties of the composites were obtained by the tensile test. The experimental result indicated that CF grafted by 0.25% weight fraction of CNT or more could develop a special microstructure similar to the micro-pits on the surface of CF, which improved the wettability of CF and PA6 due to the increased surface area and the roughness of CF. When the weight fraction of CNT reached 0.25%, the IBS increased by 41.8%, the tensile strength by 130%, and the interfacial shear strength (IFSS) by 238%. The interfacial dimple fracture was observed by Scanning Electron Microscope(SEM), which revealed that the composites were able to absorb more deforming energy before fracture. The modified surface microstructure of CF would prevent crack propagation at the interface and increase the mechanical properties of thermoplastic composites (TPCs). |
| Key words: thermoplastic composites, interfacial bonding strength, interfacial shear strength, 3D-printed molding |
| DOI：10.11916/j.issn.1005-9113.18099 |
| Clc Number:TH145.9 |
| Document Code::A |
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| Descriptions in Chinese: |
| 3D打印成型碳纤维接枝碳纳米管增强热塑性复合材料的强度提高 王婼楠1，吴海宏1，2，郭子月3，刘春太2，申长雨2 （1. 河南工业大学 机电工程学院，郑州450001; 2.郑州大学 橡塑模具国家工程研究中心，郑州450002; 3.中山大学 数学学院（珠海）,珠海519082） 创新点说明：1) 研究了碳纤维定量接枝碳纳米管对热塑性复合材料的界面性能及拉伸性能的影响。 2) 用3D打印模压成型的工艺方法制备了热塑性复合材料。 研究目的： 研究碳纤维表面接枝不同含量的碳纳米管对复合材料微观结构、界面性能和力学性能的影响。 研究方法： 1) 采用溶液法，通过控制碳纳米管接枝反应时间，制备不同含量碳纳米管接枝碳纤维，然后用硝酸刻蚀法，去除残留溶剂，验证了碳纳米管接枝的可靠性。用扫描电镜观察碳纤维的微观形貌，用FTIR测试碳纤维表面官能团并用XPS对碳纤维的表面官能团进行分析。 2) 用扫描电镜观察碳纤维与基体的结合情况并用接触角测量仪测试碳纤维与基体的接触角。 3) 通过 3D打印成型法成型了热塑性复合材料样条，并用扫描电镜观察碳纤维热塑性复合材料的界面微观形貌。 4) 采用万能试验机测试3D打印成型热塑性碳纤维复合材料的拉伸性能，并观察复合材料断口形貌。 结果： 1) 溶液法.扫描电镜观察发现碳纳米管在碳纤维表面均匀分布，表明碳纤维与碳纳米管之间存在较强的键合关系。但随着接枝时间的增加，碳纤维表面的碳纳米管含量逐渐增加，但达到0.4%时，出现分散不均匀现象。碳纤维表面含有上浆剂和去掉上浆剂的对比发现，无上浆剂的碳纤维表面沟壑明显，这些沟槽可以增加碳纤维的比表面积和表面能，增强了基体与碳纤维的机械相互作用。用FTIR测试碳纤维表面官能团并用XPS对碳纤维的表面官能团进行分析，结果表明，经偶联剂改性后，C=O键含量明显增加，碳纤维表面引入含氧官能团。C1，O1S峰增强，表明碳纳米管接枝到了碳纤维表面。 2) 扫描电镜结果表明，与表面未接枝碳纳米管的碳纤维相比，接枝碳纳米管的碳纤维与基体PA6具有更好的润湿性。接触角测试结果对比发现，接枝碳纳米管的碳纤维与基体的接触角，明显小于未接枝碳纳米管的。 3) 通过扫描电镜观察复合材料的界面微观形貌，结果表明：纤维与基体之间存在一定厚度的界面层，界面层的存在可以减轻纤维与基体之间的力学性能突变引起的应力集中，并防止界面缺陷的扩展。 4）界面结合强度测试结果表明，当碳纳米管的质量分数增加到0.25%时，复合材料的界面结合强度比未接枝碳纳米管的碳纤维增强的PA6复合材料提高了20%，比表面有环氧的碳纤维复合材料提高了41.8%。然而当碳纳米管含量大于0.4%时，界面结合强度不再继续增加。力学测试表明碳纳米管含量为0.25%的复合材料具有最高的平均模量、拉伸强度和界面剪切强度。接枝碳纳米管的碳纤维复合材料断口形貌可以观察到界面处基体中的韧窝。表明基体树脂在拔出纤维前经历了较大的塑性变形，表明纤维与基体有很好结合性。 结论： 实验结果表明，碳纳米管可以提高表面的润湿性和CF表面粗糙度。碳纳米管接枝碳纤维增强PA6与环氧上浆的碳纤维复合材料相比，当碳纳米管的质量分数达到0.25%时，复合材料的界面结合强度增加了41.8%，拉伸强度提高了130%，界面剪切强度提高了238%。然而，随着碳纳米管含量的继续增加到0.4%时，界面结合强度和力学性能就会下降。 关键词：热塑性复合材料，界面结合强度，界面剪切强度，3D打印成型 |
