咪唑-4,5-二羧酸镧的合成及其对PVC稳定性能的影响

Influences on the Synthesis of lanthanum 4,5-Imidazoledicarboxylic Acid and Its Thermal Stabilizing Effect on PVC

以咪唑-4,5-二羧酸、氢氧化钠和氣化镧为原料合成了咪唑-4,5-二羧酸镧,并对合成的产物进行了分析与表征,通过刚果红试纸法和高温老化箱实验研究了咪唑-4,5-二羧酸镧对聚氣乙烯(PVC)的影响,并与硬脂酸镧、硬脂酸辞、硬脂酸钙和季戊四醇等热稳定剂对PVC的稳定性的影响进行了比较,同时将咪唑-4,5-二羧酸镧与其他稳定剂进行了复配。结果表明,当咪唑-4,5-二羧酸镧单独作为PVC稳定剂时,抗变色能力较差,但长期稳定性较好;当咪唑-4,5-二羧酸镧:硬脂酸辞:季戊四醇的添加比例为6:2:2时,总用量为PVC的2.5%时,PVC的稳定时间可以达到49min。结果表明,咪唑-4,5-二羧酸镧的稳定机理为PVC分解释放出的氣化氢被异烟酸镧吸收生成了LaCl3,减少了HC1对PVC降解的催化作用,抑制了PVC的降解。

Lanthanum 4,5-Imidazoledicarboxylic acid was synthesized by using 4,5-Imidazoledicarboxylic acid,sodium hydroxide and lanthanum chloride as raw materials.The synthesized products were analyzed and characterized,the thermal stability and discoloration of poly (vinyl chloride) were studied by Congo red test paper and high temperature aging test,and compared with Lanthanum Stearate,zinc stearate,calcium stearate heat stabilizer on the stability of the PVC,meanwhile lanthanum 4,5-Imidazoledicarboxylic acid was rematched with other stabilizers.The results showed that the stability of lanthanum 4,5-Imidazoledicarboxylic acid alone as PVC stabilizer was not ideal,long-term stability in general,and the anti discoloration ability was not very good.The stability time of PVC reached 49 min when lanthanum 4,5-Imidazoledicarboxylic acid : stearic acid zinc : pentaerythritol = 6 : 2 : 2 total amount of PVC was 2.5%.The mechanism of lanthanum 4,5 - Imidazoledicarboxylic acid stabilization was to absorb the HCl released by the decomposition of PVC to produce LaCl3,which reduced the catalytic effect of HCl on the degradation of PVC and thus inhibits the degradation of PVC.