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Utilizing Furfural-Based Bifuran Diester as Monomer and Comonomer for High-Performance Bioplastics: Properties of Poly(butylene furanoate), Poly(butylene bifuranoate), and Their Copolyesters
journal contribution
posted on 2019-12-13, 20:15 authored by Tuomo
P. Kainulainen, Terttu I. Hukka, Hüsamettin
D. Özeren, Juho A. Sirviö, Mikael S. Hedenqvist, Juha P. HeiskanenTwo homopolyesters and a series of novel random copolyesters
were
synthesized from two bio-based diacid esters, dimethyl 2,5-furandicarboxylate,
a well-known renewable monomer, and dimethyl 2,2′-bifuran-5,5′-dicarboxylate,
a more uncommon diacid based on biochemical furfural. Compared to
homopolyesters poly(butylene furanoate) (PBF) and poly(butylene bifuranoate)
(PBBf), their random copolyesters differed dramatically in that their
melting temperatures were either lowered significantly or they showed
no crystallinity at all. However, the thermal stabilities of the homopolyesters
and the copolyesters were comparable. Based on tensile tests from
amorphous film specimens, it was concluded that the elastic moduli,
tensile strengths, and elongation at break values for all copolyesters
were similar as well, irrespective of the furan:bifuran molar ratio.
Tensile moduli of approximately 2 GPa and tensile strengths up to
66 MPa were observed for amorphous film specimens prepared from the
copolyesters. However, copolymerizing bifuran units into PBF allowed
the glass transition temperature to be increased by increasing the
amount of bifuran units. Besides enhancing the glass transition temperatures,
the bifuran units also conferred the copolyesters with significant
UV absorbance. This combined with the highly amorphous nature of the
copolyesters allowed them to be melt-pressed into highly transparent
films with very low ultraviolet light transmission. It was also found
that furan–bifuran copolyesters could be as effective, or better,
oxygen barrier materials as neat PBF or PBBf, which themselves were
found superior to common barrier polyesters such as PET.