Study On The Application Of Succinic Acid Polyester Plasticizers In PVC

Plasticizer was the largest amount auxiliaries of polyvinyl chloride(PVC),which played an important role for improving the application of PVC.At present,the most widely used plasticizers were phthalates,in which dioctyl phthalate(DOP)was most widely used.However,studies found that DOP had poor resistance to migration,and was extracted easily by organic solvent and carcinogenic potentially.Polyester plasticizer is a kind of macromolecule plasticizer,which not only has high plasticizing efficiency,good resistance to migration and low toxicity,but also was biodegradable,and the development of new environmentally friendly polyester plasticizer has important theoretical and practical significance.In this paper,a series of novel polyester plasticizers were prepared by using dibasic acid and diol as raw materials.The plasticizing effect of these plasticizers on PVC was investigated and the thermal stability was studied.Four kinds of succinic acid polyester plasticizers(PGS?PPS?PBS and PHS)were made from succinic acid and dihydric alcohol(ethanediol,1,3-propanediol,1,4-butanediol and 1,6-hexanediol),respectively,by esterification and polycondensation reaction.The structure and properties of these polyesters were characterized by FT-IR,1HNMR,GPC and DG-TGA.The results showed that the molecular weight of the four kinds of polyester plasticizers was between 900 and6000.The dynamic mechanical analysis(DMA)showed that the carbon number of the diols had great influence on the plasticizing effect of the polyesters.PHS had best plasticizing effect and highest plasticizing efficiency.The effect of PHS content and molecular weight on the plasticizing properties were investigated.The compatibility of PHS with PVC were observed and analyzed by SEM.The biodegradability of plasticized PVC samples was characterized by enzyme analysis.The results showed that the flexibility of PVC increases firstly andthen decreases with the increase of PHS content,but when the addition amount of PHS was higher than 35 phr,the agglomeration phenomenon of plasticizer was occured.When the addition amount of PHS was 35 phr,the compatibility of PHS with PVC was better,and the weight loss rate of resistance to migration,volatile and solvent-resistant extraction were lower than 0.8%;PHS comprehensive performance was better than the traditional plasticizer DOP.With the increase of the molecular weight of PHS,the durability of plasticized PVC samples was increased.The Tg of PVC and plasticizing efficiency of PHS were increased firstly and then decreased which was calculated by the Tg.When the molecular weight of PHS was 4250,the tensile strength of plasticized PVC samples was 15.84 MPa,the hardness of PVC was56 D,the Tg of PVC was 5.3?,the plasticizing efficiency of PHS was 118.1%.Compared with the monomeric plasticizer,PHS could more effectively reduce the role of PVC molecules because of long molecular chain of PHS and good lubricating effect,so PVC blends had the lower Tg.The results of analysis of enzyme degradation showed that PHS plasticized PVC samples had a certain degree of biodegradability,and the weight loss rate of the samples was 9.31% after 30 days of enzymatic degradation.TG-FTIR and X-ray photoelectron spectroscopy(XPS)were used to analyze the thermal stability of PVC.The results showed that PHS had good thermal stability.The higher the molecular weight,the better the thermal stability.When the molecular weight of PHS was 5546,the initial degradation temperature of plasticized PVC samples reached 264?,which was 13? higher than that of pure PVC.