Amorphous copolyesters based on bibenzoic acids and neopentyl glycol

Abstract

High Tg amorphous copolyester thermoplastics were synthesized by incorporating 4,4′‐bibenzoate (4,4′BB) and 3,4′‐bibenzoate moieties into the polyester backbone via melt polycondensation. The high levels of crystallinity typically associated with 4,4′BB containing polyesters were suppressed through copolymerization of ethylene glycol, 1,4‐cyclohexane dimethanol, and neopentyl glycol (NPG) diols. NPG was shown to be highly effective in suppressing crystallization and was used to produce amorphous compositions with Tg’s as high as 129 °C. Diol ratios were determined by 1H NMR spectroscopy and molecular weights were assessed with inherent viscosity (ηinh). Thermogravimetric analysis showed single‐step weight losses in the range of 395–419 °C. Differential scanning calorimetry was used to determine melting points and glass transition temperatures over a wide range of copolyester compositions and identified amorphous compositions. Dynamic mechanical analysis confirmed Tg’s and was used to study β‐relaxations below the Tg. Rheological analysis revealed the effect of NPG structures on shear thinning and thermal stability. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 579–587

Influence of Bibenzoate Regioisomers on Cyclohexanedimethanol-Based (Co)polyester Structure–Property Relationships

“…Bibenzoate-based (BB) semi-aromatic polyesters possessing mechanical properties similar to BPA-PC, T g s greater than 100 °C, oxygen barrier properties greater than poly­(ethylene terephthalate) (PET), and potentially low manufacturing cost offer a novel polymer platform for improved thermoplastics. − Enhanced mechanical, gas barrier, and thermal properties offer advantages in coating, food packaging, and high temperature electronic applications. These polyesters exhibit T g s approaching 120 °C, whereas BPA-PC T g is ∼145 °C, enabling BPA replacement in many high temperature applications.…”

Designing novel semi‐aromatic polyesters with dimethyl 3,3′‐bibenzoate

“…Melt transesterification and polycondensation enabled the synthesis of the 3,3'BB‐based polymers utilizing well‐defined polymerization procedures, depicted in Scheme 1 12–15, 17, 31, 32 . In previous studies, the titanium isopropoxide catalyst chosen for this polymerization demonstrated catalytic activity towards transesterification 33 .…”

“…Dimethyl 3,4′‐bibenzoate (3,4'BB), the kinked regioisomer of 4,4'BB, recently garnered interest after a number of studies emerged copolymerizing 4,4'BB and 3,4'BB with various diols. These studies demonstrated improvements to gas permeability and Young's modulus in the amorphous state upon increased incorporation of 3,4'BB 12–16 . This monomer imparted a higher amorphous polymer density as well as an increased entanglement density 13, 16 .…”

“…These studies demonstrated improvements to gas permeability and Young's modulus in the amorphous state upon increased incorporation of 3,4'BB. [12][13][14][15][16] This monomer imparted a higher amorphous polymer density as well as an increased entanglement density. 13,16 Studying the impact of 3,4'BB on 4,4'BB-based liquid crystalline polymers revealed destabilization of the liquid crystalline phase at high concentrations of 3,4'BB.…”

Isosorbide and Tricyclodecanedimethanol for the Synthesis of Amorphous and High Tg Partially Biobased Copolyesters

“…Several diacids/diesters such as purified terephthalic acid (PTA) and 2,5-dimethyl furanedicarboxylate − (DMFD) were also investigated. Recently, new insights have been gained on bicyclic structures such as 3,4′-bibenzoate (3,4′BB) and 4,4′-bibenzoate , (4,4′BB), indole (IND), divanillic acid, and dimethyl [2,2′-bifuran]-5,5′-dicarboxylate. , …”