Novel biobased copolyesters based on 1,2-propanediol or 2,3-butanediol with the same ethylene skeletal structure as PETG

Publication date: 17 January 2018
Source:Polymer, Volume 135
Author(s): Ji-Hyun Kim, Jong-Ryang Kim, Cheol-Hee Ahn
New potentially biobased copolyesters having the same ethylene skeletal structure as poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) were synthesized based on 1,2-propanediol (1,2-PD) or 2,3-butanediol (2,3-BD) with 1,4-cyclohexane dimethanol (CHDM). The compositions of each copolyester were confirmed using ¹H-NMR spectroscopy, and the detailed structure was analyzed using 2D NMR spectroscopy. In order to observe the effect of the lateral methyl groups on the microstructure and randomness in the sequences of the copolymers, ¹³C-NMR spectroscopy analysis was performed. The thermal properties, mechanical properties, and crystallinity of the copolyesters were analyzed using differential scanning calorimetry, thermogravimetric analysis, universal testing machine, and wide-angle X-ray diffraction. Depending on the number of the lateral methyl groups and the contents of the ethylene diol units, the copolyesters displayed different densities, glass transition temperatures (Tg), degrees of randomness and mechanical properties; however, a notable difference was not observed in thermal stability or crystallinity.

Graphical abstract

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