Study On Bisphenol-Z Block Modification Of BPA-polycarbonate Through Melt Extrusion

BPA-polycarbonate(BAPC) is widely used in various industries in the world because of its excellent comprehensive performance. Along with the rapid development of industrial technology in the word, the heat resistance of polycarbonate materials gradually exposed its insufficient. At present, only Germany Bayer Company has been developed and produced of high temperature resistant polycarbonate of PC-HT series products, almost in a monopoly position in the world. If we can use reactive extrusion method to introduce rigid group into BAPC molecular chain to improve its heat resistance, it will have a huge market prospect.For this purpose, This thesis through melt transesterification reaction to introduce rigid group into BAPC molecular chain in order that synthesize a novel structure and high glass transition temperature of the polycarbonate copolymer by twin-screw extruder, in order to make up for the deficiency of heat resistance of BAPC. Focuses on studied what the affects of bisphenol-Z(BPZ) monomer and diphenyl carbonate(DPC) of prepolymerization and condensation polymerization on the properties of modified polycarbonate. A t the same time,also explorated the ratio of raw materials, raw material drying condition, catalysts and its content, hot embossing parameters and other factors affect the performance of modified polycarbonate.Experiments show that the most appropriate prepolymerization and polycondensation extrusion process respectively is: the appropriate prepolymerization barrel temperature of each section is 230℃, 240℃, 245℃, 255℃, 260℃, 240℃(die), the melt temperature is255℃, the vacuum degree of prepolycondensation is 0.06 MPa and the screw speed is 30rpm;the appropriate polymerization barrel temperature of each section is 240℃, 250℃, 260℃,260℃, 260℃, 240℃(die), the melt temperature is 255℃, the vacuum degree of polycondensation is 0.1MPa and the screw speed is 25 rpm.Studied the performance changes of polycarbonate reactive extrusion with different catalysts and different chain extenders. The results show that the best comprehensive performance of modified polycarbonate was obtained by using sodium sulfite as catalyst, and the content of was 0.05%. The chain extenders of three types obtained modified polycarbonate with diphenyl methane-4,4’-diisocyanate(MDI) as the highest heat deformation temperature, and the content of was 0.5%. Using the molar ratio of DPC/BPZ is 1.05 and the total mass fraction of 10% can obtain the polycarbonate of heat deformation temperature is144℃ and thermal stability and mechanical properties were more excellent by solid-phase polycondensation(SSP).