N-乙基哌嗪基邻苯二甲单酰胺酸锌对PVC热稳定性能的影响

Effects of N-ethylpiperazinylphthalomide zinc on thermal stability of PVC

以邻苯二甲酸酐、N-乙基哌嗪为原料合成N-乙基哌嗪基邻苯二甲单酰胺酸,再将其与氯化锌反应制备了N-乙基哌嗪基邻苯二甲单酰胺酸锌(ZNEP),然后将ZNEP分别与季戊四醇、二苯甲酰甲烷(β-二酮)、环氧大豆油和亚磷酸一苯二异辛酯进行复配得到4种复合热稳定剂;采用刚果红试纸法、热老化烘箱法,转矩流变仪法和热重分析仪(TG)研究了不同复合热稳定剂对聚氯乙烯(PVC)静态和动态热稳定性能及热降解过程的影响。结果表明,当ZNEP、季戊四醇复配质量比为1∶2时,PVC样品的热稳定性最好,其静态热稳定时间和动态热稳定时间分别为2340 s和1602 s;同时,与不添加热稳定剂的样品相比,其质量损失率为5%、10%及质量损失速率最快时对应的温度(T_(5%)、T_(10%)、T_(max))均表现出了较大程度的提升,说明该复合热稳定剂能有效抑制PVC的热降解。

N-ethylpiperazine-based phthalate was synthesized using phthalic anhydride and N-ethylpiperazine as raw materials,and then the obtained product was reacted with zinc chloride to prepare N-ethylpiperazinylphthalomide zinc(ZNEP).Four types of composite heat stabilizers were obtained separately through compounding ZNEP with pentaerythritol,dimethylbenzoyl methane(β-diketone),epoxy soybean oil,and phenyl diisooctyl phosphate,and their effect on the static thermal stability,dynamic thermal stability and thermal degradation process of PVC was investigated using the Congo red test paper method,thermal aging oven method,torque rheometer,and thermal gravimetric analysis.The results indicated that the PVC compounds achieved an optimum thermal stability at a mass ratio of ZNEP to pentaerythritol of 1∶2.The static and dynamic thermal stability times were determined to be 2340 and 1602 s respectively.Comparing to the PVC sample without heat stabilizer,the heat-stabilized PVC exhibited an increase in T_(5%),T_(10%),and T_(max),indicating that the composite heat stabilizer can effectively inhibit the thermal degradation of PVC.