Synthesis of Furanic Polyamides and Composite Coatings from Plant Biomass

We report, for the first time, the synthesis of polyamide composite coating based on renewable plant biomass sources. 2,5-furandicarboxylic acid (FDCA) was prepared by catalytic oxidation of 5-hydroxymethylfurfural (HMF) obtained by plant biomass conversion. FDCA was used in the synthesis of aliphatic and aromatic furanic polyamides. Two approaches to furanic PAs synthesis have been investigated: (i) synthesis of hexamethylenediamine furanoate salt and its subsequent polycondensation; (ii) synthesis of FDCA dichloride and its subsequent polycondensation in a two-phase aqueous-organic system. The effect of the nature of organic solvent (tetraclormetan, dichloromethane, N-methyl-2-pyrrolidone) and the nature of diamine (hexamethylenediamine and paraphenylenediamine) on the yield and molecular weight of furanic polyamide was studied. The synthesized aliphatic polyamide was used for enamel fabrication. Colloidal graphite and activated carbon obtained from the waste of biomass conversion into HMF were used as fillers. The furanic PA composite coatings on steel provide the lower coefficient of friction and lower wear compared with that of commercial polyamide (PA6) coatings and can be considered as novel promising anti-friction coating materials.