Synthesis and characterization of poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephtlatate)-block-poly(tetramethylene oxide) copolymers

Abstract

A series of poly(ethylene terephthalate-co-1,4-cyclohexanedimethanol terephthalate)-blockpoly(tetramethylene oxide) (PETG-block-PTMO) copolymers were synthesized by means of a polycondensation process and characterized using 1 H nuclear magnetic resonance (H NMR) and Fourier transform infrared spectroscopy (FTIR), that confirm the successful synthesis of the material. Differential scanning calorimetry (DSC), small -and wide-angle X-ray diffraction (SAXS and WAXS), and thermogravimetric analysis (TGA) were used in order to evaluate the influence of the block copolymers' composition and microstructure on the phase transition temperatures, thermal properties, as well as the thermooxidative and thermal stability of the PETG-block-PTMO copolymers, respectively. The mechanical properties were investigated by tensile testing and dynamic mechanical measurements (DMTA). We found that along with an increase in PTMO weight fraction, both number-average molecular weights and intrinsic visocisities increase. Moreover, an increase in the flexible segments content in PETG-block-PTMO resulted in shifting the values of glass transition temperatures toward lower ones, which was confirmed by DSC and DMTA analyses, thus affirming the miscibility of both phases. At the same time, along with an increase of PTMO flexible segments amount in the PETG-block-PTMO copolymers, the values of Young's modulus, tensile strength at yield and weight losses in lower temperatures range, i.e. 280-390 C, decrease.

Estudo comparativo entre PETG e PLA para Impressão 3D através de caracterização térmica, química e mecânica

“…CHEN et al [55] avaliaram pela técnica de TGA a temperatura de decomposição do PETG com diferentes composições químicas e obtiveram valores de temperatura inicial de degradação entre (401,2 e 405,7) ºC, intervalo este que se aproxima ao valor observado no presente estudo. Ainda para efeitos de comparação, PASZKIEWICZ et al [56] avaliaram a degradação térmica do PETG em duas condições de atmosfera no ensaio de TGA, inerte e oxidante (ar sintético), e verificaram que as temperaturas para uma perda de 90% da massa inicial foram, respectivamente, 602,9ºC e 519,8ºC. Neste estudo, para o mesmo valor de redução de massa e utilizando-se ar sintético, a temperatura final de degradação já mencionada foi de 495ºC, indicando que essa atmosfera acelera o processo de decomposição térmica do PETG.…”

“…Neste estudo, para o mesmo valor de redução de massa e utilizando-se ar sintético, a temperatura final de degradação já mencionada foi de 495ºC, indicando que essa atmosfera acelera o processo de decomposição térmica do PETG. Por fim, o segundo estágio de degradação do PETG, mais acentuado que o do PLA, também foi observado de forma semelhante no estudo de PASZKIEWICZ et al [56]. Este efeito pode estar relacionado a um elemento da composição química do material que necessita de maior energia térmica para decompor totalmente a amostra inicial de filamento ou a resíduos da degradação Seguindo a apresentação dos resultados das análises térmicas, na Figura 7 (a) e (b) são representados os termogramas de DSC obtidos para o PLA e o PETG em diferentes condições, isto é, filamentar (inicial), impressa e injetada.…”

Accelerated physical ageing of poly(1,4-cyclohexylenedimethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol terephthalate)

“…21 These changes in mechanical properties causes physical ageing to be considered the most signicant ageing kinetic in PET that limits its service life. 22,23 PETG (T g ¼ 78 C) is synthesised as PET but substituting a fraction of the ethylene glycol with 1,4-cyclohexanedimethanol (CHDM) causes the end-product to be more ductile but T g only increases by $4 C. 24,25 A potential material could be poly(1,4-cyclohexylenedimethylene-co-2,2,4,4tetramethyl-1,3-cyclobutanediol terephthalate) (PCTT, for its structure see Fig. 1) (T g ¼ 110 C) synthesised by replacing the ethylene in PETG with the rigid 2,2,4,4-tetramethyl-1,3cyclobutanediol (TMCD) causing T g to increase signicantly, $35 C. 26 Thus, PCTT could be suitable for high temperature applications in comparison to PET and PETG.…”

Synthesis, structure, and physical properties of poly(trimethylene terephthalate)‐block‐poly(caprolactone) copolymers

“…Segmented copolyester ethers, important class of TPEs, play key role in the industrial applications. One can find Hytrel (DuPont, USA) and Anitel (DSM), a family of compounds where the rigid segment is based on PBT and the flexible segment is poly(tetramethylene oxide) (PTMO) (PBT‐ block ‐PTMO), particularly important materials in industrial applications. Our previous studies confirmed that by using two‐step melt polycondensation process, one can obtain PTT‐based copolymers which exhibit good TPEs properties with high thermal stability.…”