Study On The Preparation Of Acetylacetonate And Cyanurate And The Performance Of Thermal Stability For PVC

Polyvinyl chloride?PVC?is one of the five major general resins in the world.Due to its excellent properties,it has been widely applied in construction,telecommunications,chemical industry,packaging and other fields.However,the deficiency of the production process of PVC leads to its own defective structure,which makes the thermal stability of PVC poor and easy to give rise to thermal degradation.Therefore,it is very important to add thermal stabilizer to improve its stability.This paper focuses on the synthesis of PVC thermal stabilizers with excellent properties.Firstly,PVC auxiliary thermal stabilizer barium/zinc acetylacetonate and main stabilizer calcium/zinc cyanurate were synthesized respectively.Secondly,its influence on the thermal stability of PVC is systematically investigated.Finally,the possible mechanism of thermal stabilization is analyzed.The details are as follows:1.Barium acetylacetonate?Ba?acac?₂?and zinc acetylacetonate?Zn?acac?₂?were synthesized by one step liquid phase reaction,and the structures of the products were analyzed by elemental analysis,XRD,FTIR and TG.It is inferred that the structural formulas are Ba?C₅H₇O₂?₂·H₂O and Zn?C₅H₇O₂?₂·H₂O,respectively.Then,Ba?acac?₂and Zn?acac?₂ are used as auxiliary thermal stabilizers of CaSt₂/ZnSt₂ to evaluate the thermal stability,and the results show that:Ba?acac?₂ is an auxiliary thermal stabilizer with both initial and long term thermal stability,and Zn?acac?₂ is an efficient initial auxiliary thermal stabilizer.Meanwhile,the compound effect of Ba?acac?₂ and CaSt₂/ZnSt₂ with mass ratio of 3:1 is the best,the zinc burning phenomenon is alleviated,and the compound effect of Zn?acac?₂ and CaSt₂/ZnSt₂ with mass ratio of4:1 is the best,and the initial whiteness was greatly improved.In addition,compared with dipentaerythritol?DiPE?,epoxy soybean oil?ESBO?,Ba?acac?₂ and Zn?acac?₂,it was found that the synergistic effect of the composite system was:Ba?acac?₂>Zn?acac?₂>DiPE>ESBO.Finally,the mechanism of thermal stabilization of Ba?acac?₂and Zn?acac?₂ was analyzed.2.A new type of PVC main stabilizers calcium cyanurate and zinc cyanurate were synthesized,and the structure of the product was analyzed by elemental analysis,FTIR and TG,and the structure formula of calcium cyanurate was inferred to be Ca₃?C₆N₆O₆?₂·H₂O,the structural formula of zinc cyanurate is Zn?C₆H₄N₆O₆?·0.5H₂O.Investigating the performance of calcium/zinc cyanurate thermal stabilizer,it was found that zinc cyanurate is a good initial thermal stabilizer,and its ability to inhibit zinc burning is better than zinc stearate.Calcium cyanurate is a long-term thermal stabilizer with a higher thermal stability time than calcium stearate.When the calcium/zinc cyanurate binary system is compounded,the synergistic effect of the mass ratio of 3:1 is the best.In addition,in order to further improve the properties of PVC products,based on calcium/zinc cyanurate binary system,ESBO and DiPE were added as auxiliary thermal stabilizers,and various testing methods were used to find that the thermal stability was significantly improved.DiPE has outstanding ability in inhibiting zinc burning,so it has excellent long-term thermal stability.ESBO can not only improve the initial whiteness of the system,but also greatly improve the long-term performance.Finally,the possible thermal stability mechanism of calcium/zinc cyanurate system was analyzed.