乙基双马来酰胺酸类物质对聚氯乙烯的热稳定及修复性能的影响

Effect of Ethyl Bismaleamic Acid on Thermal Stability and Repair Performance of Polyvinyl Chloride

以马来酸酐和乙二胺为原料采用溶剂法合成乙基双马来酰胺酸(H2L),经乙基双马来酰胺酸与氢氧化钙的固相共研磨成功合成出乙基双马来酰胺酸钙(CaL)。通过红外光谱(FT-IR)、元素分析等表征其结构与性能;将合成的H2L或CaL与聚氯乙烯(PVC)均匀混合,利用刚果红试验测试其对PVC的静态热稳定时间;PVC在200℃油浴中热解得降解PVC,将H2L或CaL分别与降解PVC均匀混合后在双辊塑炼机上塑化、热压成型,进行力学性能测试,采用FT-IR对修复前后的PVC进行测试,并对修复后的PVC断面形貌进行扫描电镜观察。结果表明,所合成的H2L和CaL都可以作为PVC的热稳定剂,CaL对PVC的热稳定作用更优,且H2L可以对降解PVC进行性能修复,拉伸强度和断裂伸长率修复率分别达到了109.8%和150.3%.其修复是通过双马来酰胺酸与降解PVC中的共轭双烯发生Diels-Alder反应实现的。

Ethyl bismaleamic acid(H2L)was synthesized by the reaction of maleic anhydride and ethylenediamine through solvent method,and the basic complex of ethyl bismaleate calcium(CaL)was successfully prepared by solid phase co-milling H2L with calcium hydroxide.Its structure was characterized by FT-IR and elemental analysis;the H2L and CaL were separately mixed with polyvinyl chloride(H2L/PVC,CaL/PVC samples)and the static thermal stability time of these samples were evaluated by Congo red test.The thermal degradation of these polyvinyl chloride(PVC)samples were obtained under 200°C oil bath,the mechanical properties test of H2L/PVC,CaL/PVC samples were plasticized by double-roll plasticizing machine and hot-pressed,mechanical properties test,the cross-section of H2L/PVC,CaL/PVC samples before and after repaired were also investigated by FT-IR analysis and SEM analysis.The results indicate that H2L and CaL both could be added as thermal stabilizer of PVC and the thermal stability of CaL is relatively better.What′s more,H2L could repair the thermally degraded PVC.The repair rates of tensile strength and elongation at break reach 109.8%and 150.3%,respectively.The repair mechanism is realized by Diels-Alder reaction of bismaleamic acid and conjugated diene in degraded PVC.