固化剂混掺对高温下CFRP板-钢板界面黏结性能的影响

针对单一固化剂难以兼顾耐热性和韧性的不足，研究了耐热性能较好的缩胺105和韧性较好的聚醚胺D230两种固化剂混掺对纳米SiO₂环氧胶黏剂玻璃转变温度及高温下基本力学性能的影响。按一定固化条件制作了30个胶黏剂拉伸试件、21个碳纤维增强树脂复合材料(CFRP)板-钢板双搭接试件，进行了高温及常温下的准静态拉伸试验、拉伸剪切试验，测试了相应胶黏剂的动态热机械性能，并与常用商品胶的耐热性能与力学性能进行比较，得到以下结论:随混掺固化剂中聚醚胺D230比重的增加，胶黏剂高温下的拉伸强度及弹性模量逐渐降低，断裂伸长率及应变能先增加后减小，缩胺105与聚醚胺D230两种固化剂混掺的推荐比例为1∶2。随固化温度的升高，具有固化剂混掺较佳比例的胶黏剂的玻璃转变温度有所提升，综合技术与经济因素，推荐(较佳)固化条件为90℃、2 h。推荐比例与推荐固化条件的纳米SiO₂环氧胶黏剂在环境温度20~70℃之间的拉伸强度及韧性均大大优于常用商品胶黏剂。基于推荐比例与推荐固化工艺的纳米SiO₂胶黏剂粘结的CFRP板-钢板搭接接头，在70℃服役温度下的荷载-位移曲线存在屈服段，承载能力(较采用单一缩胺105和单一聚醚胺D230固化剂的搭接试件分别提升了104.03%、64.43%)和延性(为采用单一缩胺105固化剂的搭接试件的2.5倍以上)均大幅提升。高温和常温下的黏结-滑移本构均为三线性四边形。胶黏剂在满足耐热性的同时，需尽可能提升其韧性，才能有效提升CFRP-钢搭接界面的力学性能。相比于常用商品胶黏剂，研制的推荐胶黏剂粘结的CFRP板-钢板搭接接头具有优越得多的承载能力和界面断裂能。 

Effect of curing agent mixing on interfacial bond behavior of glued CFRP plate-steel plate at elevated temperature

Aiming at the shortcoming that it is difficult for a single curing agent to simultaneously meet the requirements of heat resistance and toughness, the influence of the mixing of two curing agents (Condensationamine 105 with excellent heat resistance and amino-terminated polyoxypropylene D230 with good toughness) on the glass transition temperature T_g and basic mechanical properties of the nano-SiO₂ epoxy adhesive at elevated temperature was analyzed. According to certain curing conditions, a total of 30 adhesive tensile test pieces and 21 carbon fiber reinforced polymer (CFRP) plate-steel double lap test pieces were fabricated, and quasi-static tensile tests and shear tensile tests were performed at elevated and room temperatures. The dynamic thermodynamic properties of the corresponding adhesives were tested and compared with the heat resistance and mechanical properties of commonly used commercial adhesives. The results show that the preferred ratio of the two curing agents of condensationamine 105 and amino-terminated polyoxypropylene D230 is 1∶2. With the increase of the curing temperature, the T_g of the adhesive with the preferred ratio of two mixed curing agent is increased. Based on comprehensive technical and economic factors, the recommended (preferred) curing condition is 90℃ for 2 h. The tensile strength and toughness of the nano-SiO₂ epoxy adhesive with the recommended ratio and the recommended curing conditions between ambient temperature 20~70℃ are better than the commonly used commercial adhesives. The load-displacement curve of CFRP plate-steel lap joint based on nano-SiO₂ adhesive with recommended ratio and recommended curing process has a yield section at the service temperature of 70℃, and the bearing capacity (Compared with the lap joint based on nano-SiO₂ adhesive with a single condensationamine 105 and a single amino-terminated polyoxypropylene 230 curing agent, the bearing capacity of the lap joint has been increased by 104.03% and 64.43%, respectively) and ductility (It is more than 2.5 times of the lap joints using a single amine 105 curing agent) are greatly improved. The bond-slip constitutive can be simplified as a trilinear quadrilateral model at elevated temperature and room temperature. Under the premise of satisfying heat resistance, the toughness of the adhesive needs to be improved as much as possible to effectively enhance the bonded behavior of the CFRP-steel lap interface. The recommended adhesive-bonded CFRP plate-steel lap joint has much superior load-bearing capacity and interface fracture energy compared with commonly used commercial adhesives.