The Synthesis And Characterization Of Bisphenol-A Polycarbonate With Triphosgene

Firstly, the liquid- liquid reaction system, which was formed by the triphosgene in CH2Cl2 and bisphenol A in NaOH solution, was investigated by measuring the conductance and PH value of the water phase, And the effects of temperature, thickness, diffusing area, catalyst, and time, etc were studied. During the procession, there was no stirring.After that, we probed into the reaction mechanism with experiments phenomenon, and got some useful conclusions: The reaction needs catalyzer, which can shorten the reacting time, and make the reaction process fully. Among the several types of catalyzers, Et3N is the best choice. It not only catalyses BTC to form phosgene but also is phase-tranfer-catalyzer to accelerate the diffusion of both polycarbonate chain and BPANa; The reaction is controlled by diffusion with no stirring. The enlargement of diffusion area is be favorable to the reaction of BTC and BPA; Heightening reaction temperature can promote the reaction.Secondly, based on the results of the experiments above, we synthesized various molecular weight polycarbonate. Among them, the ultra high molecular weight was very important. During this process, the affects of stirring rate, temperature, thickness, diffusing area, catalyst, and time, etc were researched detailedly. The GPC experiment of ultra high molecular weight polycarbonateshowed that the Mw is 172000 and the Pd is 1.413, which was much lower than the common bisphenol A polycarbonate. The TGA curve of ultra high molecular weight polycarbonate indicated that the initial temperature in nitrogen was 486C and was 468C in air, which make it possible to heighten molding temperature making up for the increase of melt viscidity induced by the rise of molecular weight. In addition, the products were characterized by FTIR, DSC, XRD. etcFinally, the reaction mechanism and course were investigated. We found that the reaction had became emulsion polycondensation from interfacial polycondendation, which was completely different with the reaction of phosgene and BPA.