Poly(ethylene terephthalate) copolymers that contain 5‐tert‐butylisophthalic acid and 1‐3/1‐4‐cyclohexanedimethanol: Synthesis, characterization, and properties

Abstract

The effects of incorporating 5-tert-butylisophthalic acid ( t BI) and 1-3/1-4 cyclohexanedimethanol (CHDM) in the polymer chain of poly(ethylene terephthalate) (PET) on the crystallization behavior and thermal, optical and tensile properties of this polyester (PETGB) were evaluated. These random copolyesters that contained between 0 and 20 mol % of CHDM and between 0 and 10 mol % of t BI units were prepared by esterification followed by melt copolycondensation. The compositions and molecular weights of the copolyesters were determined by 1 H-NMR spectroscopy and viscometry, respectively. The composition of the polyester was consistent with the composition of the feed. The intrinsic viscosities of the copolymers ranged between 0.62 and 0.74 dL/g. The ther-mal behaviors were investigated over the entire range of copolymer compositions, using DSC under the heating and cooling rate of 208C/min and TGA. The copolyesters with t BI and CHDM of < 20 mol % were crystallizable, whereas the copolyesters with t BI and CHDM of 20 mol % were amorphous. They appeared to be stable up to 3958C. The optical transmissions of the amorphous polyesters were more than 88% in the visible region. The mechanical behavior was investigated by performing a tensile test.

Synthesis, characterization, and properties of degradable poly(l‐lactic acid)/poly(butylene terephthalate) copolyesters containing 1,4‐cyclohexanedimethanol

“…To verify the molecular structures and to determine the chemical compositions, all of the copolyesters were characterized by 1 H‐NMR and FTIR spectroscopy. According to previous studies, 8, 20, 21, 26, 28, 29 several probable existent segment units in the main chains of PBCTLs are shown in Figure 1, and their corresponding characteristic peaks were assigned as shown in Figure 2, which presents a typical 1 H‐NMR spectrum of the PBCTL‐2 copolyester. The peaks centered at 8.10, 4.43, and 1.97 ppm were assigned to the protons (H 1 ) of the benzene ring, OC H 2 (H 4 ), and adjacent C H 2 (H 12) of butylene terephthalate moiety, respectively, whereas the signals at 4.36–4.22 ppm corresponded to OC H 2 (H 5, 6, 7) of butylenedioxy covalently linked to terephthalate and/or lactate.…”

Chemical Structure and Microstructure of Poly(alkylene terephthalate)s, their Copolyesters, and their Blends as Studied by NMR

“…A second example of PET modified by copolymerization is provided by the widely known poly(ethylene‐ co ‐cyclohexylenedimethylene terephthalate) copolyesters (PE x C y T), which were developed by Eastman Chemical Co. with the aim at affording amorphous PET polymers able to combine an excellent transparency with a high chemical resistance and toughness . In these copolyesters, part of EG is replaced by 1,4‐cyclohexylenedimethanol (CHDM).…”

Amorphous copolyesters based on 1,3/1,4‐cyclohexanedimethanol: Synthesis, characterization and properties

“…The details of the synthesis can be found elsewhere. [9][10][11] In each preparation, the reaction mixture comprised excess EG, various amounts of diol and diacid (molar ratio of diol/diacid 5 1.4), 350 ppm Ti(O(CH 2 ) 3 CH 3 ) 4 and 90 ppm Co(OAc) 2 by weight. The reaction mixture was heated to the final temperature (220-2508C) in an atmosphere of nitrogen, and was stirred at a constant speed (500 rpm).…”

“…8 We recently synthesized a PET copolymer by copolymerizing 1,3/1,4-CHDM, EG, 5-tert-butylisophthalic acid, and TPA. 9 This polyester is amorphous and has the optical transmission about 88%. To obtain 1,3/1,4-CHDM-based amorphous copolyesters with various values of T g for different shrinkable film applications, this work reports the preparation and properties of several series of new polyesters PETGN and PETGS, which are the derivatives of 1,3/1,4-CHDM-based PETG.…”