石墨烯和多壁碳纳米管改性环氧胶粘剂性能的实验研究

EXPERIMENTAL INVESTIGATION ON BONDING PROPERTY OF EPOXY ADHESIVE MODIFIED BY GRAPHENE AND MULTI-WALL CARBON NANOTUBES

为了提高环氧胶粘剂的粘接性能和热学性能,采用石墨烯和多壁碳纳米管(MWCNTs)分别单独改性和按照比例(1∶1)混合改性环氧胶粘剂。制备了碳纤维增强复合材料层合板的单搭接剪切试样,通过拉伸实验测试了改性前后胶粘剂的剪切强度;运用扫描电子显微镜(SEM)分析了改性胶粘剂的胶层断裂机理;结合热失重分析(TGA)和差示扫描量热法(DSC)研究了纳米材料改性对环氧胶粘剂热学性能的影响。结果表明:石墨烯和MWCNTs改性提高了环氧胶粘剂的界面粘附力和剪切强度。此外,改性具有协同作用。当添加0.5wt%石墨烯和MWCNTs混合改性时,剪切强度达到最强,提高34.52%,在此最优含量下,改性环氧胶粘剂的分解温度也最高,因此热稳定性最好。但是,纳米材料的改性受到团聚的影响,含量过高时,增强效果呈现降低趋势。DSC结果表明,石墨烯和MWCNTs改性基本不会影响环氧胶粘剂玻璃转变温度。

To improve the bonding property and thermal property of epoxy adhesive, graphene and multi-wall carbon nanotubes (MWCNTs) were separately and proportionally (1 ∶1) added into the adhesive. Single-lap shear specimens of carbon fiber reinforced composite laminates were prepared for testing the shear strength of the unmodified adhesive and the modified adhesive. The fracture mechanism of modified adhesive layer was investigated using Scanning Electron Microscope (SEM). The effects of nano-materials on the thermal property of modified epoxy adhesive were studied using Thermo-gravimetric Analysis (TGA) and Differential Scanning Calorimeter (DSC). The results show that adding graphene and MWCNTs can improve the interfacial adhesion force of epoxy adhesive and the shear strength of single-lap joints. In addition, the modification has a synergistic effect, when 0.5wt% graphene and MWCNTs were added for hybrid modification, the shear strength of the single-lap joints is the strongest, increasing by 34.52%. At the optimum content, the decomposition temperature of the modified epoxy adhesive is also the highest, and thus the thermal stability is the best. However, the reinforcement of nano-materials at higher content tends to decrease due to their agglomeration. The DSC results show that the modification of graphene and MWCNTs does not affect the glass transition temperature of the epoxy adhesive.