Synthesis And Analysis On The Characteristics Of Poly(Ethylene Terephthalant) With Various Catalyst And Copolyester

Poly(ethylene terephthaltae)(PET)is one kind of saturated polyester,which is synthesis from terephthalic acid and glycol.PET is a typical linear thermoplastic material and a kind of semi-crystalline polymer.It has not only high impact modulus,outstanding stability,excellent resistance to chemicals,but also avirulence,,wearable and rigid properties,it has been used in field as fiber,packaging bottle,film and engineering plastic application.However,there some disadvantage of PET hold it back been used more widely which was there low tension strength of PET melting,crystallize slowly,and sensitivity for oxygen.Modified PET through in-situ copolymerization can endow new polyesters with excellent performances and capacious applications of polyester products.In this study,Poly(ethylene terephthalate)(PET)with various intrinsic viscosity were prepared by 1 L autoclave using terephthalic acid(TPA)and ethylene glycol(EG)in the presence of Sb2O3 as catalyst.The rheological properties of all samples have carried on the comparative analysis by shear and elongational rheometry.The influence of intrinsic viscosity,temperature,and shear rate to the apparent complex viscosity,zero shear viscosity,and viscous flow activation energy are discussed.It was found that all samples were typical shear thinning non-newtonian fluid,and the complex viscosity was decreased with the increasing of shear rate and temperature.In addition,with the increase of the intrinsic viscosity,the zero shear viscosity and viscous flow activation energy of samples also gradually increased.Next,using antimony catalyst,germanium catalyst or titanium catalyst,the PET chip was produced on 1 L autoclave.The effects of catalyst to the reaction process and the properties of the product were studied.The synthesis results showed that the optimum conditions were: esterification temperature was 230 ?,condensation temperature was 275 ?,the catalyst's dosage was 1.5‰ of PTA moles.The germanium catalyst activity was lower comparative to antimony catalyst and titanium catalyst,and germanium catalyst contributed lower L value and better thermal stability.In the end,co-poly(ethylene terephthalate-co cyelohexanedimethyllene terephthalade)(PETG)is synthesized with the PTA,EG,and CHDM.In addition,the influence of different amount of CHDM to the crystallization behavior,thermal property and mechanical property were studied.The results show that Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(1H-NMR)test showed that then synthesized product was PETG co-polyester.The glass transition temperature(Tg)increase and melt temperature decrease with CHDM content increase.The regulatity of the molecular chain of PETG is destroyed,which influences its crystallization.The DMTA results that Storage Modulus was the most highest when the CHDM content was 10%.