The Synthesis And Application Research Of A Novel Stabilizer With Both Thermal And Light Stability For PVC

With the development of economy and the improvement of people's living standards,the application of plastics has become a new hot spot in the market and the plastic has become an indispensable material in the automotive,aerospace,electronics,building,agriculture and other areas.As is known to all,the five most popular plastics consist of polyethylene(PE),polypropylene(PP),polyvinyl chloride(PVC),polystyrene(PS)and acrylonitrile-butadiene-styrene copolymer(ABS)resin,in which the production of PVC is highest in China and ranks second in the world,and PVC materials,widely used in chemical industry,construction,electronics,agriculture and other fields,has a variety of excellent performance,such as high mechanical strength,good transparency,antiflaming,resistance to chemical attack,and so on.However,there is unstable chlorine on the actual PVC chain,which easily lead to PVC thermal degradation to release hydrogen chloride gas in the process of heating,changing the appearance and mechanical properties of product,so PVC has poor thermal stabilization.And as result of properties of PVC that can absorb ultraviolet,PVC will be autoxidation under the sunlight or strong fluorescence,giving rise to light degradation and poor resistance to light for PVC material.Therefore,it is particularly important for PVC industry to improve the thermal and light stability for PVC.And now the main way to solve this problem is various stabilizers' addition into PVC.A new PVC stabilizer was synthesized in the paper,the metal salts of hindered 4-piperidinol monoesters with dicarboxylic acids,specifically including[1-(2,2,6,6-tetramethyl-4-piperidinyl)-ester]-2-calcium benzoate,[1-(2,2,6,6-tetramethyl-4-piperidinyl)-ester]-2-lanthanum benzoate and[1-(2,2,6,6-tetramethyl-4-piperidinyl)-ester]-2-cerium benzoate.There is a specific synthetic method that firstly the intermediate product of hindered 4-piperidinol monoesters with dicarboxylic acids was prepared by esterification reaction of phthalic anhydride with 2,2,6,6-tetramethyl-4-piperidinol,and then reacted with sodium hydroxide and inorganic salts giving target product,the structure of which was confirmed by FTIR and NMR.In the paper,the thermal and light stability of these metal salts of hindered 4-piperidinol monoesters with dicarboxylic acids for PVC were researched through Congo red method and ultraviolet aging experiment,respectively.We found that these metal salts have good effect on PVC and their order of heat stability is Ce salt>Ca salt>La salt by Congo red method.There are better synergistic effects of these metal salts with zinc stearate than the traditional Ca/Zn composite stabilizer and the order is Ca salt/zinc stearate>La salt/zinc stearate>Ce salt/zinc stearate,the best ratio of which are 5:5,5:5 and 7:3,respectively.Through ultraviolet aging experiment,we found that these metal salts have good light stability on PVC and the order is Ce salt>La salt>Ca salt and Ca stearate/Zn stearate composite stabilizer and other metal soaps don't have.However,there is no synergistic effects of these metal salts with zinc stearate against light degradation for PVC.