Synthesis and Thermal Characterization of a Series of Copolyesters Synthesized from Terephthaloyl Chloride, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and Bisphenol A, AF, F, and HPF

Abstract

The synthesis of copolyesters which contain both aromatic as well as aliphatic dial monomer units has been conducted The rigidity of 2,2,4,4-tetramethyl-1,3- cyclobutanediol (CBDO) makes it a viable candidate to replace or use along with rigid aromatic dials. Bisphenols A, AF, F, and HPF have also been used as the aforementioned aromatic dials due to their common industrial use. Copolymers of CBDO, terephthaloyl chloride, and the various bisphenols were synthesized and characterized for structure and thermal properties The percent incorporation of the CBDO and bisphenol were varied in order to examine the effect on thermal properties The structure of these various copolymers was verified by fourier-transform infrared spectroscopy (FTIR), as well as gel-permeation chromatography (GPC), and nuclear magnetic resonance spectroscopy (NMR). The latter yielding information not only about the structure, but also about the percent cis and trans CBDO, as well as the percent CBDO in the copolyester. The cis to trans ratio did not fluctuate from the original CBDO monomer, while the percent CBDO in the copolyesters remained within 5% of the feed ratio initially used for the reaction. GPC was used to determine the weight average molecular weight of the copolymers, these ranged from 6,415 to 28,826. The decomposition temperatures of these copolymers, determined by thermal gravimetric analysis (TGA), ranged from 359 °C for the Bisphenol-F copolymer to 472 °C for the Bisphenol-HPF copolymer. The glass transition temperatures, determined by differential scanning calorimetry (DSC), ranged from 163 °C for the Bisphenol-HPF copolymer to 215 °C for the Bisphenol-AF copolymer. Although the molecular weights were low compared to commercial polymers, glass transitions higher than 100 °C and decomposition temperatures higher than 350 °C were obtained and make for very useful optical plastic materials.