The Research Of Chemical Synthesis Process Of Fluorene Polycarbonate

Polycarbonate is an excellent thermoplastic engineering plastics with not only high impact strength, excellent thermal stability and resistance to cold, but also good electrical insulation, flame retardant, which has been widely used in CD-ROM production, automotive, packaging, pharmaceutical and other industries. The glass transition temperature of traditional bisphenol-A polycarbonate is 140℃–160℃,The deformation will occurrent easily at a high temperature, which cannot meet some special fields of national economy needs. So the modification of thermal properties of polycarbonate is becoming more and more important.The technology about improving the thermal performance of polycarbonate is still in the blank in China. So this paper used bisphenol-fluorine instead of bisphenol-A as raw material to synthesis polycarbonate in order to study the influence of different groups on the glass transition temperature, which can make up the poor thermal performance and low glass transition temperature of bisphenol-A polycarbonate.According to the reaction process of using ester exchange method to synthesis polycarbonate, it can be divided into two independent reaction phases which is Ester exchange phase and polycondensation phase.All sorts of factors, including the type and concentration of catalysts, reaction temperature, reaction time and reaction pressure were discussed. La(acac)₃ was found that it has better catalytic effect than others. The ester exchange was belonging to pseudo-first-order reaction at pre polycondensation stage. Conditions of polycondensation reaction: final reaction temperature for 320℃, eventually pressure < 1mmHg, reaction time for 8h. FTIR, NMR and DSC confirmed that polycarbonate was successful synthesis, and the glass-transition temperature and thermostability of polycarbonate was very high.