Synthesis and characterization of soluble polyester based on calixarene dicarboxylic acid with tertiary butyl pendant groups

Abstract

A series of new polycalixesters (PCES) were synthesized by polyesterification of calixarene dicarboxylic acid derivatives having tertiary butyl pendant groups at the upper rim using five different diols. All polyesters were readily soluble in polar solvents such as NMP (N-methylpyrrolidone), DMF (dimethylformamide), DMSO (dimethylsulfoxide), pyridine, THF (tetrahydrofurane), HMPA (hexamethylenephosphoramide) and DMAC (dimethylacetamide). The PCES were also partially soluble in TCE (tetrachloroethane) and ethanol and they were unsoluble in aceton. The glass transition temperatures of polyesters were between 80–184 °C, the crystallinity temperatures of polyesters were between 130–212 °C and the melting temperatures of polyesters were between 185–234 °C, as determined by differential scanning calorimeter (DSC). The inherent viscosities of polyesters were obtained from 0.55 dL/mg to 0.61 dL/mg. The temperatures at 10% weight loss of polyesters ranged from 182 °C to 237 °C. The temperatures at 25% weight loss of polyesters ranged from 258 °C to 331 °C. The half weight loss (50%) temperatures of polyesters were among 315 °C to 371 °C and the char yields at 600 °C were determined within 13% to 22.3% in N₂ atmosphere, as determined by thermo gravimetric analysis (TGA). The polyester, PES3, has the higher melting point (234 °C) and higher inherent viscosity (molecular weight) than the other polyesters.