碳酸铈复合热稳定剂的研究

Study on cerium carbonate compound thermal stabilizers

无毒环保的稀土类热稳定剂由于其热稳定效果良好且价格适中,越来越受到人们的重视。目前研究较多的是脂肪酸稀土热稳定剂,但关于无机盐稀土稳定剂的报道甚少。采用碳酸铈单独作热稳定剂,以及与三碱式硫酸铅二元复配作热稳定剂,应用刚果红法考察其对PVC热稳定性的影响。研究结果表明,单一碳酸铈具有一定的热稳定作用,这主要是由于稀土可与多个氯原子配位,使PVC的C-Cl键得到了稳定,从而提高了PVC的热稳定性;只用碳酸铈作为热稳定剂时,碳酸铈加入质量分数为2.0%时的效果最好,热降解温度200℃,热稳定时间646s;碳酸铈、三碱式硫酸铅以质量比为1∶1复配后综合效果最好,PVC热降解温度204℃,热稳定时间2211s。

Rare earth thermal stabilizer attracts more and more attention because it is non-toxic, environment-friendly,efficient and economical. Fatty acid rare earth thermal stabilizer is widely studied,however there seldom has any report about inorganic salt rare earth is used as thermal stabilizer. Thermal stability of polyvinyl chloride resin （ PVC ） upon doping cerium carbonate as well as compound binary-ingredient thermal stabilizer （i. e. cerium carbonate and tribasic lead sulfate） was determined by means of Congo red test method. Results showed that cerium carbonate could stabilize PVC because cerium can coordinate with multi CI atoms which makes C - Cl bond in PVC stabilized. When cerium carbonate was used as thermal stabilizer alone with preferable proportion of 2% （mass fraction） , temperature of thermal degradation of PVC was 200 ℃ and thermal stable period was 646 s. The PVC doping compound stabilizer at a ratio of cerium carbonate ：tribasic lead sulfate of 1：1 （mass ratio） also displayed excellent thermal stability, decomposition temperature of PVC was 204 ℃, and thermal stable period was 2 211 s.