基于间乙烯脲键的可重复加工交联PMMA的合成与制备

Synthesis and Preparation of Reprocessable Cross-Linked PMMA based on Vinylogous Urea Bond

通过自由基聚合,将间乙烯脲键(VU-a)与商业化聚合单体——甲基丙烯酸甲酯(MMA)化学整合得到可重复加工的含VU-a的MMA交联聚合物(VU-a-PMMA)且无需催化剂参与反应。通过溶胀、溶解测试证明了VU-a的可逆性,使用电子万能试验机、同步热分析仪和动态热机械分析仪对VU-a-PMMA的拉伸性能、热稳定性、动态热机械性能进行了表征分析。结果表明,VU-a-PMMA的首次拉伸强度为40.9 MPa,断裂伸长率为4.33%,经历3次粉碎加热成型循环后的拉伸强度为31.2 MPa,断裂伸长率为3.31%;失重5%及最大失重速率温度分别为271℃,430℃,玻璃化转变温度为94℃。随着温度的升高,VU-a-PMMA有着更短的松弛时间,通过阿伦尼乌斯分析预测了VU-a-PMMA在180℃下的应力松弛时间约为169 s。

The vinylogous urea(VU-a)was synthesized and integrated with a commercial polymerized monomer—methyl methacrylate(MMA),through free radical polymerization to obtain a reprocessable cross-linked polymer material(VU-a-PMMA)without any catalyst.The reversibility of the VU-a was proved by swelling and dissolution tests,then,the tensile properties,thermal stability and dynamic thermo-mechanical properties of VU-a-PMMA were characterized and analyzed by electronic universal testing machine,synchronous thermal analyzer and dynamic thermo-mechanical analyzer.The results show that the tensile strength of VU-a-PMMA reaches 40.9 MPa,and the elongation at break is 4.33%.After three cycles of pulverization and remolding,the tensile strength is 31.2 MPa,and the elongation at break is 3.31%.The temperature of 5%weight loss and the maximum weight loss rate are 271℃and 430℃,respectively,and the glass transition temperature is 94℃.With the temperature rising up,the relaxation time of the VU-a-PMMA become shorter,and the stress relaxation time of VU-a-PMMA at 180℃was predicted to be about 169 s by the Arrhenius analysis.