Study on the Preparation and Optical Properties of Co-polycarbonates Based on Binaphthalene and Cardo Structures

Copolymer carbonate was synthesized from diphenyl carbonate (DPC), 9, 9-bis [3-phenyl-4 -(2-hydroxyethoxy) phenyl] fluorene (BPPEF) and 2,2 ' -bis (2-hydroxy-ethoxy)-1,1 ' -binaphthalene (BHEBN) by melt transesterification. The composition and random structure of the copolymer were determined by FT-IR, H-1 NMR and C-13 NMR analysis. DSC and TGA analysis showed that Cardo structure could significantly increase the glass transition temperature and thermal decomposition temperature. With the addition of BHEBN, the refractive index of copolymer was increased, but the thermal properties of copolymer were decreased. It is found that the contribution of naphthalene structure to the refractive index of the polymer material is higher than that of benzene structure. When the dosage of BHEBN is 42 mol %, the glass transition temperature (Tg) of the copolymer is 141.8 degrees C, the maximum thermal decomposition temperature is 421.9 degrees C, the refractive index is 1.6535, the Abbe number is 21, the transmittance is 88.29 %, and the birefringence is negative 0.01x10(-3).