Study On The Small Test And Amplification Technology Of Polycarbonate By Melt Transesterification

Polycarbonate is insufficient to supply the demand indomestic, but the immature process and the monopoly of foreign companies are the main problems of polycarbonate, which has not solved for many years. This paper contrasts many methods to synthesize the polycarbonate. The method of non-phosgene melt transesterification is friendly to the environment, leading a correct way to the development of polycarbonate in our country. In this paper, the process of polycondensation in a kettle using the non-phosgene melt transesterification was investigated, and then the expanding test according to the results of small-scale test was conducted.In the process of small-scale test, the molecular weight and colour was used as the main index of the polycarbonate product. The effects on the change of small molecular with reaction time, the condensation polymerization time, temperature, pressure of polycondensation, and the speed of rotation to the reaction were analyzed. The result shows that it can produce the best product when the polycondensation temperature is260℃, the time is1.5h, the speed of rotation is150r/min, the end pressure of polycondensation is100Pa, which react as the better process condition of the small test.After enlarging the small test, there is the problem of low molecular weight. Through the study of the main factors which influence the molecular weight in the enlarging experiment, the main factors on molecular weight were found, which were the initial material ratio> the end temperature of polycondensation> the time of polycondensation> the amount of catalyst. The optimization conditions are the initial material ratio n(DPC): n(BPA)=1.15:1, the propolymer catalyst5х10-5mol HLcat-1for the basis of per mol BPA, the antioxidants KYJ-10.5%o, the reaction temperature170℃, the pressure3000Pa, and the polycondensation catalyst1.5х10-5mol HLcat-2for the basis of per mol BPA, the antioxidants KYJ-1is2%o, the end pressure100Pa, the speed of rotation90r/min, the reaction temperature260℃, the reaction time is4h. Finally, the structure and the mechanical properties of polycarbonate product were tested.