Experimental Research On Synthesis Of Prepolymer Of Polycarbonate Through Melt Transesterification Process

This paper comprehensive reviews the methods for synthesis of bisphenol-A polycarbonate(PC). The non-phosgene synthesis route of melt transesterification method is determined for polycarbonate prepolymer process by comparing the other methods. Syhthesis of prepolymer of polycarbonate by melt transesterification with diphenyl carbonate and bisphenol-A is studied in a flask. Through the small scale experiments in the flask, the pre-polymerization catalyst was investigated to determine the tetrabutylammonium hydroxide as a catalyst to get the best overall performance of the product. Then the main factors were investigated such as the amount of catalyst, the material ratio, the kind of antioxidant, the amount of toner, purity of diphenyl carbonate and bisphenol A, and the amount of quencher on the prepolymer product performance. On this basis, the pre-polymerization conditions such as motor speed, quenching agent dosage were investigated in the stainless steel reactor. Finally, the kinetic was studied for the pre-polymerization system, and the experimental results shows a good agreement with the assumed kinetic model. The results have some guidance for the follow-up experiment. The optimal conditions of the reaction are as follows: catalyst tetrabutyl ammonium hydroxide, the amount of 5×10-5 mol/molBPA, DPC used after crystallization, using K7 as antioxidants, the amount of 0.6%; using organic acid as quencher, the amount of 5ppm; the catalyst was added at 150℃, preliminary transesterification reaction 30 min, the final temperature of 230℃, and keeping 10 min. The molecular weight of PC prepolymer preapred meets the requirements of polycondensation, the color and light transmission rate of PC prepolymer reaches world-class level.