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A series of novel-sulfonated furanic polyesteramides have been synthesized by polycondensation in the melt-phase. The copolymers were obtained with reasonable molecular weights and high inherent viscosities between 0.2 and 0.4 dL/g. The hydrolytic degradability of polyesteramides was enhanced by the increasing of amide units in the copolymers backbone.

In order to prepare furanic–aliphatic polyesteramides without the side reactions taking place with furan-2-carboxylic acids or esters, a furan-based diamine, 5,5′-isopropylidenebis(2-furfurylamine), was reacted in the bulk, either with (i) ethanediol and dimethyl adipate or (ii) with the corresponding aliphatic polyester (polyethylene adipate). The polycondensation involves both amine–ester and hydroxy–ester interchanges, with elimination of excess ethanediol. High-molar-mass furanic–aliphatic polyesteramides were easily obtained. Method (ii) was more efficient than method (i), but no side reactions were observed with both methods. These polyesteramides behave as amorphous random copolymers.

Polyesteramides based on diethyl 5,5′-(propane-2,2-diyl)-bis(furan-2-carboxylate), a biobased diester, are synthesized by high temperature bulk polycondensation with mixtures of hexane-1,6-diamine and ethane-1,2-diol. The ester/amide ratio in final copolymers is governed by the initial diester/diamine ratio, any diol excess being eliminated during the synthesis via a series of interchange reactions. The copolyesteramides are thermally stable, amorphous compounds. Their structural characterization shows the existence of minor side reactions: diol etherification, and two reactions, specific to furan-2-carboxylate structure, the formation of nonreactive 2-furyl end groups and chain branching resulting from amidine formation by amide–amine condensation.