Study on synthesis and characterization to high glass transition temperature of the polycarbonate

Abstract

Copolycarbonates of bisphenol-A prepared with various bisphenol monomers have attracted attention as a means of tuning specific physical properties. For example, copolycarbonates based on bisphenol-A and bisphenol fluorene (BPF) have high resistance to thermal deformation and degradation. And a copolycarbonate with bisphenol-A and bisphenol trimethylcyclohexane(BPTMC) has become available to meet the demand for amorphous materials with higher heat resistance, i.e., higher Tg than BPA-PC. We proposed new copolycarbonates with high glass transition temperature by these monomers (BPA, BPTMC, and BPF). The new copolycarbonates, by the melt-process copolymerization, were successfully synthesized for counterbalance of their advantages and disadvantages. Although the copolycarbonates containing bisphenol fluorene and bisphenol-A have excellent thermal properties, its relatively high melt viscosity leads to poor melt processability. This problem makes it very difficult to form the amorphous condition by methods known such as extrusion, injection molding, and the like. Thus, there is a need for a copolymer having a combination of two or more properties, chosen from at least one of the following: high glass transition temperature, flowability, good impact strength, and transparency. The new high heat copolycarbonates were characterized with 1H NMR, differential scanning calorimetry, and UV-vis spectroscopy. High Tgs are attributed to the high heat resistance effect of copolycarbonates by the bulky structure, which prevents rotational mobility in bisphenol phenylene rings and suppress the formation of lump of polymerization.