3D printing of a recycled copolyester of terephthalic acid, cyclohexanedimethanol and tetramethylcyclobutanediol

2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) is a diol monomer for terephthalic acid (TPA) class of copo-lyesters that can increase the glass transition temperature and mechanical strength in comparison to conven-tional TPA polyesters. TMCD-modified poly (1,4-cyclohexylenedimethylene terephthalate) (PCTT) has been used to manufacture consumer products with good toughness, heat resistance and clarity. However, the suitability of PCTT in 3D printing had not been evaluated. Therefore, consumer plasticware was used as the starting material to investigate the suitability of this copolyester for fused deposition modeling (FDM). Chemical structure, me-chanical properties, thermal behavior and viscoelastic properties of this copolyester were studied. NMR spec-troscopy found that the copolyester had cyclohexanedimethanol (CHDM) and TMCD contents at 76.5 mol% and 20 mol% of total diol, respectively. 280 degrees C printing temperature and 110 degrees C bed temperature were suitable conditions for printing. Tg of PCTT was 103 degrees C (25 degrees C higher than PETG). Young's modulus and impact strength of printed PCTT were at least 100% and 65% higher than printed PETG, respectively. The ease of printing, superior mechanical properties and Tg (103 degrees C) make the PCTT random copolyester highly applicable in additive manufacturing.

Automated summary

2,2,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) is a diol monomer that can enhance the properties of terephthalic acid (TPA) polyesters. TMCD-modified poly (1,4-cyclohexylenedimethylene terephthalate) (PCTT) has been used to manufacture consumer products with improved toughness, heat resistance, and clarity. However, its suitability for 3D printing has not been evaluated.