Synthesis and properties of copolyesters of p,p′‐bibenzoic acid, dimer acid, and alkylene glycol

Abstract

Copolyesters of p,pЈ-bibenzoic acid, dimer acid, and an alkylene glycol are prepared by melt polycondensation of of dimethyl p,pЈ-bibenzoate, dimer acid, and an alkylene glycol. The copolyesters are characterized by the inherent viscosity, FTIR, proton NMR, DSC, polarized microscopy, and X-ray diffraction. The polymer composition and sequence distribution of the copolyesters can be seen from the NMR spectra. The copolyesters exhibit a degree of randomness of about 1, indicating that they are random copolymers. The glass-transition temperature (T g ) and the melting point (T m ) of the copolyesters are found from the DSC heating curves. When the content of the flexible dimer acid unit increases, the T g of the copolyesters decreases significantly. The copolymerization effect decreases the crystallinity and the T m of the copolyesters. It can be seen from the DSC, polarized microscopy, and X-ray diffraction data that some copolyesters derived from 1,6-hexanediol and 1,5-pentanediol exhibit a monotropic smectic phase. As the molar content of the dimer acid unit increases, the isotropicmectic transition temperature and the smectic order decreases significantly. The liquid crystallinity is completely destroyed at certain molar contents of the dimer acid unit. The smectic order of the copolyesters derived from 1,6-hexanediol is significantly higher than that of the copolyesters derived from 1,5-pentanediol, and it is described as an odd-even effect.

High Molecular Weight Polyesters Derived from Biobased 1,5-Pentanediol and a Variety of Aliphatic Diacids: Synthesis, Characterization, and Thermo-Mechanical Properties

“…In 1957, Korshak et al reported the synthesis of poly­(1,5-pentylene adipate) (PPeA) and poly­(1,5-pentylene grutarate) (PPeG) for the first time. Recently, several PeDO-based aliphatic polyesters including poly­(1,5-pentylene succinate) (PPeS), − PPeA, poly­(1,5-pentylene pimelate) (PPePi), aromatic polyesters such as poly­(1,5-pentylene furanoate) (PPeF) ,,− and poly­(pentylene diphthalate), and copolyesters ,,, have been synthesized and characterized. Also, PeD-derived copolycarbonates synthesized via nonphosgene process, poly­(ester-carbonate)­s synthesized via interesterification–polycondensation, and functional copolyesters synthesized via enzymatic catalysis and used for drug release were also reported.…”

“…When succinic anhydride was used instead of succinic acid, mediium intrinsic viscosity PPeS (0.65 dL/g) was synthesized. Meanwhile, some medium to high molecular weight PeDO-based copolyesters were synthesized by Greiner et al, Tsai et al, and Li et al For aromatic polyester, only medium intrinsic viscosity (0.53 dL/g) was reported for PPeF …”

“…When succinic anhydride was used instead of succinic acid, mediium intrinsic viscosity PPeS (0.65 dL/g) 12 was synthesized. Meanwhile, some medium to high molecular weight PeDObased copolyesters were synthesized by Greiner et al, 16 Tsai et al, 23 and Li et al 24 For aromatic polyester, only medium intrinsic viscosity (0.53 dL/g) was reported for PPeF. 19 As PeDO is an odd-carbon diol monomer, aliphatic poly(1,5pentylene dicarboxylate)s could be odd−even or odd−odd polyesters and therefore may have thermo-mechanical properties different from the more common even−even aliphatic polyesters.…”