The Preparation And Application Of PVC Compund Stabilizer

Polyvinyl chloride (PVC) is a heat-sensitive resin, it is easy to degradation releasing HC1 at high temperature and high shear, cause products discoloration, heat stabilizers are indispensable additive in PVC processing, which can improve the degradation temperature of PVC, makes it possible to molding. With the strengthening of environmental awareness and enforcement of related environmental regulations and conventions, research and application of PVC stabilizers is toward non-toxic and environmentally friendly direction.This thesis synthesis a variety of organic heat stabilizers of barbituric acid derivatives and Schiff base, then compounded with stearates (CaSt2 and ZnSt2) and hydrotalcite (LDH), systematically studied the influence of heat stabilizer system constituent on PVC static and dynamic stability and processing performance.Syntheticing p-hydroxybenzaldehyde barbituric acid, p-dimethylaminobenzaldehyde barbituric acid and cinnamic aldehyde barbituric acid, exploring the synthetic route and process conditions influence, the optimum condition for synthesis:temperature 85℃, reaction time 45 min. By nuclear magnetic resonance structure of three kinds of derivatives have been characterized.On the basis of research the thermal stability, barbituric acid and its derivatives with CaSt2 heat-stable system are studied, The results showed that:CaSt2 can improve the stability of the composite stabilizer, the cinnamic aldehyde barbituric acid/CaSt2 heat stabilizer system has best stabilizing effect.LDH and other appropriate auxiliary stabilizer system can significantly improve thermal stability results of cinnamic aldehyde barbituric acid/CaSt2 heat stabilizer system. Through experimental tests, the best ratio of cinnamic aldehyde barbituric acid /CaSt2/LDH composite heat stabilizer system is 5/2/3.The research shows that vanillin schiff bases optimum conditions:temperature 78℃, reaction time 2h, crystallization time 48h. characterized and tested the vanillin schiff bases modification with FTIR.Investigate vanillin schiff bases/CaSt2 and vanillin schiff bases/ZnSt2 binary complex thermal stability system, the results show:stearates can significantly improve the thermal stability of PVC static stability time, indicate that stearates have apparent synergies with vanillin schiff bases, and zinc stearate has better synergies than calcium stearate.Modified LDH has strong ability of adsorb and displacement HC1 in vanillin schiff base/ZnSt2,prepare a ternary complex thermal stability system. Experimental results show that:with the increase in the proportion of LDH composite in heat stabilizer system, the static and dynamic stability of PVC system Showed a decreasing trend after the first increase, the processing performance of PVC is significantly increased with LDH content increased. Comprehensive comparison, the best ratio of vanillin schiff base/ZnSt2/LDH composite heat stabilizer system is 5/3/2.