Bio-based polyamides from 2,5-furandicarboxylic acid

Abstract

Biobased polymers is one of the pathways to achieve more sustainable plastics and products. Polyamides (PA) are commodity polymers, having versatile ap-plications from fibers in clothes to car parts. The most produced polyamides (PA6 and PA66) account for yearly fossil-fuel consumption of almost 10 mil-lion tonnes. The detrimental effects do not only concern the production phase, but also the consumption and end-of-life aspects. Hence, there is a crucial need to develop bio-based polyamides that are chemically recyclable to reduce the environmental impact of these materials.

In this work, furan-based polyamides (FPAs) were synthesized through a poly-condensation reaction between hexamethylenediamine (HMDA) and a bio-based diacid, 2,5-furandicarboxylic acid (FDCA). In addition, copolymers were made by using different ratios of C6 and C10 diamines (HMDA and 1,10-decanediamine). The structure and chemical composition of the synthesized polymers and copolymers were confirmed using Fourier-transform infrared spectroscopy, and proton nuclear magnetic resonance. The highest molecular weight attained was 9900 g/mol, mainly due to limitations from the reactor setup (absence of a vacuum system and lack of adequate mixing). Adding to this, the degradation of FDCA and the evaporation of HMDA were identified as potential factors inhibiting the increase in molecular weight. Based on the thermal analyses, the FPAs were found to be amorphous, with an average glass transition temperature of 102°C. Further, the synthesized polyamides showed high thermal stability, having an initial degradation temperature (cor-responding to 5% weight loss) of 340°C.

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