Studies on synthesis and optical properties of poly(isosorbide-co-1,4-cyclohexanedimethanol) carbonate

Copolycarbonate was synthesized by melt transesterification method, using diphenyl carbonate, isosorbide and 1,4-cyclohexanedimethanol (CHDM) as raw materials. The copolymer composition and random structure of the copolymer were determined by Fourier transform infrared and 1 H NMR analysis. The DSC and TGA analysis showed that CHDM was introduced into the isosorbide polycarbonate chain, which effectively lowered the glass transition temperature of the polymer without lowering the thermal decomposition temperature. The glass transition temperature of the copolymer can be controlled by the addition amount of CHDM, and its processing performance can be improved. In addition, the introduction of CHDM did not reduce the high light transmittance (> 91.5%) of isosorbide polycarbonate. With the gradual increase of the amount of CHDM added, the refractive index of the copolymer decreases slightly. When the CHDM content is 30 mol%, the glass transition temperature (Tg)of the copolymer is 132.2 °C, the thermal decomposition temperature is > 350 °C, the refractive index is 1.4960, the Abbe number is 51, and the transmittance is 91.6%, and the haze is 1.07%.