Synthesis Of Silicone Modified Polyester And Properties Of Plasticized PVC

Polyvinyl chloride(PVC)is one of the most widely used plastic materials,however duo to the strong polarity between molecules,pure PVC materials have high hardness,brittleness,difficult to process,so additives need added into PVC material to improve the flexibility of PVC.Plasticizer is the largest amount of a kind of auxiliary,and phthalate is the largest amount of all plasticizers.But phthalate is a kind of monotype plasticizer,the stability of plasticized PVC blends is poor,it is easy to migrate from PVC,and it has potential carcinogenicity.Therefore,it is extremely urgent to develop a new type of green and healthy plasticizer.Polyester is polycondensation of dibasic acid and dibasic alcohol,co MPared with the monotype plasticizer,it has excellent migration resistance,but its plasticizing efficiency is lower than the traditional monotype phthalate plasticizer.Based on the research of polyester plasticizer,the Si-O-Si group was introduced into polyester,and the polyester was modified with its good flexibility.The effects of different modification methods on the plasticizing efficiency of polyester were discussed.Hydroxy-terminated poly(hexanediol succinic)(PHS)was synthesized by condensation polymerization of succinic acid and hexanediol.And it was modified by hydroxyl condensation reaction with hydroxyl silicone oil and PHS to improve its plasticizing efficiency.And the modification product MHA was obtained It was found that When the molecular weight of hydroxy silicone oil was 5%(MPHS-2)of the molecular weight of succinic acid and the content of MPHS-2 was 40 phr,the plasticizing efficiency of MPHS reached 137.05%,which was 51.72%higher than that of PHS.FTIR spectrum and XPS analysis showed that,co MPared with pure MPHS,the C=O absorption peak of MPHS plasticized PVC blends was shifted to the lower wavenumber,and the Si-O-Si bond energy of MPHS plasticized PVC blends was also reduced by 0.5ev.This was because the hydrogen bonding interaction between Si-O-Si,C=O of MPHS and the?-H of PVC respectively in the PVC/MPHS blends.The presence of hydrogen bond increased the interaction between PVC and MPHS and caused the further improvement of plasticizing efficiency and the stability for MPHS.Poly(hexanediol maleic)(MH)was synthesized using maleic acide and hexanediol by condensation polymerization.1,1,3,3-tetramethyl(TD)was used as modifier to modified MH by hydrosilicon?hydrogenation reaction,the Si-O-Si segment was introduced as branch chain on MH main chain,TD modified poly(hexadiol maleate)(MHA)was successfully synthesized.It was found that the hydrosilicon?hydrogenation modification effectively improved the plasticizing efficiency of MH,reflecting on the decreased T_g and the increased elongation at break of PVC blends.The migration resistance analysis showed that the migration of MHA-2did not exceed 2%,which was the best among these plasticizers,while the max migration of DOP was up to 20%and and the lowest still was 12.47%respectively.According to the FTIR and XPS analysis,it is found that the polar groups of PVC molecules interact with the polar groups of MHA to produce hydrogen bonds,which improves the flexibility and stability of plasticized PVC samples.