Study On The Application Performance Of2-Methylsuccinic Acid Polyester Plasticizers

Polyvinyl chloride (PVC) is one of the largest output synthetic resin products in theworld, can be made into many kinds of rigid and soft products. Currently the mostwidely used plasticizers are phthalates, in which dioctyl phthalate (DOP) is mostwidely used. However, recent studies have found DOP be carcinogenic potentially, sotheir application is limited. Compared to conventional monomeric plasticizers DOP,polyester plasticizer has a high molecular weight, which offers low volatility combinedwith outstanding resistance to be extraction by oils and solvents, and displays excellentcompatibility with polymer materials. Polyester plasticizer is one of the developmenttendencies of plasticizers. In this paper, a series of polyester plasticizers using biomasschemical product, itaconic acid, as raw materials, was prepared. Then the plasticizingeffect, durability and biodegradable performance of these polyester plasticizers weretested after compounding with PVC.Four kinds of2-methylsuccinic acid polyester plasticizers(1,2PPM、1,3PPM、1,3PBM and1,4PBM) were synthesized from2-methylsuccinic acid made inlaboratory and dihydric alcohol (1,2-propanediol,1,3-propanediol,1,3-butanedioland1,4-butanediol), respectively, with tetrabutyl titanate catalyzed by esterificationand polycondensation reaction. The structure and properties of these polyesters werecharacterized by FT-IR,1HNMR, GPC and DG-TGA; the compatibility of plasticizersto PVC was investigated using solubility parameter method. The results showed thatthese polyester plasticizers in this study were consistent with the target products, themolecular weight between2000and3000, with excellent thermal stability and goodcompatibility with PVC, meeting the basic requirements of plasticizer.The PVC blends were made by adding Ca-Zn compound stabilizer and four kinds of2-methylsuccinic acid polyester, respectively, as plasticizers to PVC resin. The tensileproperties, plasticizing efficiency, durability（volatility resistance, extractability andmigration stability）of the PVC films were measured. Furthermore, the compatibility ofthe four kinds polyester plasticizers with PVC was observed and analyzed by SEM.Also, the impact of the content and the molecular weight of the polyester plasticizerson plasticizing effect were investigated.The Tensile measurement results showed that polyester plasticizers synthesized displayed high plasticizing efficiency, better materialcompatibility with PVC. The adding of polyester plasticizers can be greatly reduce theglass transition temperature of PVC, and made PVC be excellent in durability. Theoverall performance of these four kinds of polyester plasticizers was better than theconventional plasticizer DOP. With the increase of the content of the polyesterplasticizer, the flexibility of PVC increased, but the plasticizer began agglomeration.Furthermore with the increase of the molecular weight of the polyester plasticizer, theplasticizing effect began worse, and the softness of PVC decreased, but the durabilitywas greatly improved.The biodegradablity of the polyester plasticizers in PVC was also studied.Theenzymatic degradation was performed in phosphate buffer solution with porcinepancrease lipase (pH=7.4), and characterized by weight loss and the change of surfacetopography of plasticized PVC films. The results showed that four kinds of polyesterplasticizers have excellent biodegradability. The lower the molecular weight, themolecular chain structure more supple, the farther apart the ester bond and the lesshydrophobic methyl, the biodegradability of polyester plasticizer more excellent.