Synthesis of antimony tris
(mercaptoethyl carboxylates)
as thermal stabilizer for polyvinyl chloride
(mercaptoethyl carboxylates)
as thermal stabilizer for polyvinyl chloride
(College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China)
Central South University, Changsha 410083, China)
Abstract: A novel type of thermal stabilizers—antimony tris(mercaptoethyl carboxylates) (Sb(SCH2CH2OOCR) 3), was synthesized from carboxylic acid, antimony trioxide and 2-mercaptoethanol in two steps. The experimental results show that the molar ratio of carboxylic acid to antimony tris(2-hydroxyethyl mercaptide) is 1.2, when adding 0.6% tetra-n-butyl titanate as catalyst and xylene as isotropic solvent, heating and refluxing for about 2~4h. The thermal stability was measured by heat-aging oven test. The thermal stability time is about 8~40min(at 200℃) when adding 2% tetra-n-butyl titanate in polyvinyl chloride(PVC). Among these stabilizers, antimony tris(mercaptoethyl stearate) has best thermal stability. Its thermal stability is better than that of Ca-Zn complex and basic lead stabilizers, and equal to that of organotin. In addition, the stabilization mechanism of this kind of stabilizers for PVC was discussed briefly.
Key words: PVC thermal stabilizer; antimony mercaptan; synthesis; thermal stability