微波调控石墨烯-碳纳米管协同增强聚氨酯损伤自修复研究

Investigation on the Self-healing of Damage on Polyurethane Synergistically Reinforced by Graphene-carbon Nanotube under Microwave Radiation

首先采用溶液共混法制备出石墨烯-碳纳米管(G-CNT)/聚氨酯(TPU)复合材料,然后通过拉伸实验及扫描电子显微镜(SEM)表征来考察该材料的拉伸强度和微波自修复特性,并从力学及材料与微波之间的相互作用等角度对其拉伸强度增强和微波修复机理进行研究.结果表明:在拉伸强度方面,与单一的石墨烯或CNT增强TPU相比,G-CNT之间形成的协同效应使TPU拉伸强度得到进一步提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU抗拉强度较纯TPU提高了67%,较G/TPU提高了18%,较CNT/TPU提高了25%;在材料裂纹的微波修复方面,石墨烯和CNT之间的协同效应使TPU材料自修复效果得到有效提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU修复效果达到最高值117%.

To make up for the limited mechanical strength of polyurethane （TPU） material, carbon nanotube （CNT） and graphene （G） were added as reinforced phase into TPU matrix. The mechanical property of this CNT-G/TPU nanocomposite as well as its self-healing property under microwave processing were studied. Firstly, the solution mixing method was adopted to prepare the polyurethane nano-composite filled with carbon nanotube and graphene. Then the mechanical property of this G-CNT/TPU nanocomposite was investigated by tensile testing. Mechanics principle analysis and scanning electron microscopy （SEM） were used to study the mechanisms of mechanical enhancement of this material. Secondly, self-healing property of these nanocomposites under microwave electromagnetic fields was also studied through the crack-repair processing, tensile testing and SEM characterization. Moreover, the mechanisms of both mechanical enhancement and self-healing under microwave radiation were studied. The results indicated that, in terms of mechanical properties, there was synergetic reinforcement effect between the graphene and CNT, which could further improve the mechanical performance of G-CNT/TPU nanocomposites when compared with the samples that were only reinforced with CNT or grapheme. With the ratio of graphene to CNT at 3：1, the mechanical properties of G-CNT/TPU composites reached the optimum value of 70.6 MPa. The tensile strength of G-CNT/TPU composites increased by 67% when compared with that of pure TPU materials, by 18% when compared with that of G/TPU composites, and increased by 25% when compared with that of CNT/TPU composites. In term of the self-healing of cracks in the material under microwave radiation, the results showed that these G-CNT/TPU composites could be healed effectively and rapidly by microwave electromagnetic radiation. Besides, it was shown that the self-healing efficiency could be further improved by the synergy effect between graphene and CNT. With the ratio of graphene to CNT at 3：1, the self-healing of G-CNT/TPU composite reached the best result, which was about 117% of the virgin composite.