【摘要】 橡胶材料通常因经过硫化及补强等工艺处理而呈现出热固性,因而难以被回收处理,容易造成严重的资源浪费和环境污染.本文通过在聚丁二烯上修饰羧酸基团,再加入锌离子(Zn2+)与羧酸配位,制备了基于金属配位键交联的自修复橡胶(PB-COOH/Zn2+).该橡胶具有良好的机械性能和优秀的自修复及重塑性能,在70℃下修复3 h,其韧性可以恢复到初始强度,修复效率可达100%. PB-COOH/Zn2+较高的聚合物链段运动能力及配位键交联网络良好的动态性不仅赋予其优异的修复性能,还使得其在较温和的条件下可以进行多次重塑,在70℃及5 MPa的条件下重塑3次仍能保持原有的机械性能.此外,通过在PB-COOH/Zn2+中掺杂适量的碳纳米管,不仅增强了其机械性能,还使其具备了电致修复及传感能力,扩宽了PB-COOH/Zn2+作为环境友好型材料的应用前景.更多还原

【Abstract】 To meet the requirements of high mechanical performance in various practical applications,rubber must be chemically cross-linked to form a 3 D covalent network. However,the formation of a chemical crosslinked network classifies rubber as a thermoset material,which hinders the reshaping and recycling of rubber,causing waste of resource and severe environmental pollution. To solve this problem,a cross-linked network evolved from metal coordination interaction is introduced to the polybutadiene system to prepare a self-healing rubber material with admirable reprocessing ability. The self-healing rubber materials are fabricated by attaching carboxyl group to polybutadiene,followed by cross-linking through the metal coordination interaction between Zn2+and carboxyl group(the resulting materials are denoted as PB-COOH/Zn2+). The PB-COOH/Zn2+exhibits tensile stress of 6.30 MPa,ultimate strain of 2284%,Young’s modulus of 1.68 MPa,and toughness of 68.66 MJ/m3. Benefitting from high mobility of the polymer chain and excellent dynamic performance of the metal coordination interaction,PB-COOH/Zn2+has excellent self-healing and recycling abilities. The mechanical properties of the damaged PB-COOH/Zn2+almost completely recover after healing at 70 ℃ for 3 h. The healing efficiency of PB-COOH/Zn2+,which is defined as the ratio of the restored toughness to the original one,is 100%. In addition,PB-COOH/Zn2+can be reprocessed by hot pressing at 70 ℃ with the pressure of5 MPa for 10 min. The recycled PB-COOH/Zn2+still maintains quite stable mechanical properties after three reprocessing processes. The mechanical properties of the metal coordination elastomer can be further improved by doping PB-COOH/Zn2+with multi wall carbon nanotubs(MWCNTs). The Young’s modulus of the PBCOOH/Zn2+doped with 40%(mass fraction)MWCNTs(denoted as PB-COOH/Zn2+/MWCNTs-40)is improved to 8.21 MPa. Doping with MWCNTs doesn’t affect the self-healing and recycling abilities of materials. The conductivity of MWCNTs endows the PB-COOH/Zn2+/MWCNTs with potential to transduce electrical energy into Joule heating energy to accomplish electro-thermal healing process and sensing application,which extend its potential applications as environmental-friendly materials.更多还原