Highly renewable, thermoplastic tetrapolyesters based on hydroquinone, p‐hydroxybenzoic acid or its derivatives, phloretic acid, and dodecanedioic acid

ABSTRACT A series of tetrapolyesters were obtained by polymerizing phloretic acid, hydroquinone, p‐hydroxybenzoic acid, or its derivatives, that is, vanillic acid or syringic acid, and dodecanedioic acid. Each monomer was polymerized in its acetylated form, except for the diacid to undergo polymerization by acidolysis. Initial polymerizations had shown that the use of phloretic acid resulted in better polymer properties than with p‐coumaric acid. The predominantly renewable polymers were obtained by melt polymerization using a two‐stage condensation process whereby antimony(III) oxide was applied as catalyst. Monomer conversions were typically close to 90%. 1H and 13C NMR, DSC, TGA, solution viscometry, and GPC were applied, as well as polarized microscopy to determine polymer microstructure and composition, transition temperatures, decomposition temperatures, intrinsic viscosities, and other molecular weight properties, and when applicable the liquid crystalline behavior of the polymers. All peaks, including end group peaks in the 13C NMR spectra were assigned, the monomer sequence distribution was verified to be random, and a complete dyad analysis involving nine dyads and eight peaks was performed. By using p‐hydroxybenzoic acid and its derivatives without any, one or two methoxy groups and varying the copolymer compositions, melting temperatures could be tuned between 106 and 181 °C. The tetrapolyesters, which included residues of p‐hydroxybenzoic acid, formed nematic liquid crystals. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1498–1507 Highly renewable copolymers could be polymerized from acetylated monomers based on hydroquinone (HQ), p‐hydroxybenzoic acid (BA) or its derivatives, vanillic acid (VanA, R = OCH3, R′ = H) or syringic acid (SyrA, R = R′ = OCH3), phloretic acid (PhlA), and dodecane dioic acid (Dod). All dyad peaks for the tetrapolyesters were assigned. The melting points decrease from 181 to 106 °C as the methoxy group contents of the polymers increased.