Poly(ethylene) Terephthalate , PET, is synthesized from purified Bis-hydroxyethyl Terephthalate,(BHET), in the presence of antimony oxide catalyst. Rate constant for the polycondensation reaction, based on a second order kinetic model is found to be 152.4/mol/hr.
A new modified polyester Polyethylene Adipic Terephthalate (PEAT) is synthesized from BHET and adipic acid. The effect of adipic acid content in the copolymer,on the rate of polycondensation is studied. Adipic acid is shown to improve the activity of the polymer chain ends thereby increasing the apparent reaction rate constants.
The modified polyesters are observed to melt at a lower temperature than PET. Moreover, the temperature of maximum crystallization is significantly decreased. This property of PEAT would allow a much lower mold temperature during processing and improve the crystallization rate.
|