Fully Aromatic Thermotropic Copolyesters Based on Vanillic, Hydroxybenzoic, and Hydroxybiphenylcarboxylic Acids.

Several series of new polymers were synthesized in this study: binary copolyesters of vanillic (VA) and 4'-hydroxybiphenyl-4-carboxylic (HBCA) acids, as well as ternary copolyesters additionally containing 4-hydroxybenzoic acid (HBA) and obtained via three different ways (in solution, in melt, and in solid state). The high values of logarithmic intrinsic viscosities and the insolubility of several samples proved their high molecular weights. It was found that the use of vanillic acid leads to the production of copolyesters with a relatively high glass transition temperature (~130 °C).

Synthesis and Properties of Thermotropic Copolyesters Based on Poly(ethylene terephthalate) and 4'-Acetoxy-4-biphenyl-carboxylic Acid.

A series of novel copolyesters based on polyethylene terephthalate (PET) and 4'-hydroxy-biphenyl-4-carboxylic acid (HBCA) was obtained by melt polycondensation of (2-hydroxyethyl) terephthalate and 4'-acetoxybiphenyl-4-carboxylic acid (ABCA) as co-monomers with SbO as a catalyst. Using this synthetic procedure, a set of copolymers containing 20-80 mol% of HBCA units was prepared. According to NMR spectroscopy, the copolymers were of random composition.