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

Repeatable molecularly recyclable semi‐aromatic polyesters derived from lignin

“…The presence of the acetoxy group is a prerequisite, and the amount of base is decisive. [ 27 ] The base will first deprotonate the carboxylic group and thereby enhances its nucleophilicity, as shown in step i in Scheme 2. Subsequently, the deprotonated acid group attacks the acetoxy group of the other monomer.…”

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

“…The most promising lignin-based polyester monomers are phenolic acids: vanillic, syringic, 4-hydroxybenzoic, floretic (3-(4-hydroxyphenyl)propionic), 4-hydroxycinnamic, ferulic (3-methoxy-4-hydroxycinnamic), dihydroferulic, etc. [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. 4-Hydroxybenzoic and vanillic acids are aromatic self-condensable AB-type monomers.…”

Effects of Mesogenic Cycloaliphatic Units on the Microstructure and Properties of Thermotropic Liquid Crystalline Polyesters

“…Thermotropic liquid crystalline polymers (TLCPs) with mesogenic units in the main chain have been extensively researched and commercially succeeded owing to their excellent thermal stability, mechanical strength, chemical resistance, and low linear thermal expansion coefficient [1–9] . In the 1970s, poly(hydroxybenzoic acid) (PHBA) synthesized using 4‐hydroxybenzoic acid (HBA) as a representative mesogenic unit has been reported.…”

“…Thermotropic liquid crystalline polymers (TLCPs) with mesogenic units in the main chain have been extensively researched and commercially succeeded owing to their excellent thermal stability, mechanical strength, chemical resistance, and low linear thermal expansion coefficient. [1][2][3][4][5][6][7][8][9] In the 1970s, poly(hydroxybenzoic acid) (PHBA) synthesized using 4-hydroxybenzoic acid (HBA) as a representative mesogenic unit has been reported. However, since it has an extremely high melting temperature and the decomposition reaction occurs before melting, efforts to lower the melting temperature for facile processing have been attempted.…”