Preparation Of Multisegment Copolyester And Blend With Polycarbonate

In this paper, the polycarbonate was blended with different polyesters to improvethe process property. At the same time, the effect of these polyesters on the otherperformance of polycarbonate was discussed. The polycaprolactone was prepared by ε -caprolactone opening ringpolymerization using ethylene glycol as initial agent at 175 ℃ . And thenpolycaprolacton was blended with polycarbonate. According to the result of melt index,the process property of polycarbonate was improved by introducing PCL. In the DSCcurves, the blends have only one glass transition temperature, which indicated that thesystems were miscible. As far as the mechanic properties is concerned, the tensilestrength of blends could increase about 10% and impact strength dropped sharplybecause PCL was added into PC. The SEM photo of impact breaking face showed thatthe PC/PCL blends was fragile. PET-PCL multisegment coplyester was synthesized using PTA, ethylene glycol,and low molecular weight PCL, and PECT-PCL was also prepared employing PTAethylene glycol, 1,4-cyclohexane dimethanol(CHDM), and low molecular weight PCL.These two coplyester were thermo plastic polyester elastomer (TPEE). According to theanalyses of the TPEEs, the chain structure was very complicated because of esterchanging between PET(or PECT) and PCL. Compared with PET-PCL, the chainregularity of PECT-PCL decreased, and the hard segment crystallinity was low becauseof CHDM in the copolyester. These two coplyester differed in properties as their chainstructure was discrepancy. Then PC was blended with the two synthesized coplyester. The composites wereanalysesed by MI, DSC, SEM, and mechanic property. The effect of the copolyestersstructure on the performance of PC was discussed. The results indicated that the twocopolyesters were miscible in PC. And the process property of PC was improved byintroducing the copolyesters into it. In the experiments, the composite had goodperformance, while the content of PECT-PCL multi-copolyester containing 25%PCLwas 20% in the system. In this condition, the tensile strength increased about iABSTRACT10%,and the MI was 10 times as large as that of pure PC, while the impact strength wasunchanged. The SEM result of the breaking face indicated that the blend was tough.