Copolycarbonates of bio-based rigid isosorbide and flexible 1,4-cyclohexanedimethanol: Merits over bisphenol-A based polycarbonates

Publication date: 5 May 2017
Source:Polymer, Volume 116
Author(s): Seul-A Park, Jaehoon Choi, Sungbin Ju, Jonggeon Jegal, Kang Mun Lee, Sung Yeon Hwang, Dongyeop X. Oh, Jeyoung Park
From an industrial/engineering point of view, the greatest demerit of solely isosorbide (ISB)-based polycarbonate is its fragility; this is considerably overcome in this study by using a dual-diol strategy with 1,4-cyclohexanedimethanol (CHDM). A series of copolycarbonates of ISB, a bio-derived diol with a rigid heterocyclic structure, and ductile CHDM monomers with diphenyl carbonate were prepared by transesterification polymerization. The weight-average molecular weight of the polycarbonates gradually decreases as the ratio of ISB increases; however, their Tg and storage modulus increase. The ultimate elongation of the copolycarbonates is enhanced from 4.6 to 20% as the content of CHDM is increased from 30 to 80 mol%. ISB content greater than 50 mol% makes the copolycarbonates strong but brittle, and ISB content less than 50 mol% makes the copolycarbonates ductile but soft. The polycarbonate with 70/30 mol% of ISB/CHDM shows a 1.25-fold higher Young's modulus, 1.05-fold higher ultimate tensile strength, and one-grade higher pencil hardness than the bisphenol-A (BPA)-based polycarbonate. Interestingly, the hydrophilic ISB content does not affect the degree of hydrophilicity of the copolycarbonate samples. Water droplet contact angles are in the range of 81–87°, comparable to that of the BPA-based polycarbonate.

Graphical abstract

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