Amphiphilic Biobased Polyesters from 1,4-Butanedioic Acid and 3-Allyloxy-1,2-Propanediol Carrying Carboxyl Side Groups

Herein, we present the synthesis of novel biobased amphiphilic polyesters (PE) by the combination of polycondensation and postmodification reactions. Precursor polymers were prepared by melt polycondensation of 1,4-butanedioic acid (succinic acid) and 3-allyloxy-1,2-propanediol. The molecular weight of obtained PE was adjusted by the variation of reaction parameters such as temperature, catalyst amount, and reaction time. The structure of obtained PE was confirmed by 1H NMR and Fourier transform infrared spectroscopy. In addition, the thermal properties of PE were analyzed by thermal gravimetric analyses and differential scanning calorimeter. Functional water-soluble PE were produced from precursor polymers via postmodification using a thiol-ene reaction. To incorporate carboxylic acid groups into the polymers, mercaptosuccinic acid (MSA) was applied. The modification degree and amount of carboxylic acid groups in the polyester structure can be varied by the MSA concentration in the reaction mixture as evidenced by 1H NMR spectroscopy. Interfacial tension measurements indicate that obtained amphiphilic PE exhibit surface active properties in aqueous solutions. Moreover, the acid numbers for synthesized PE were determined by potentiometric titration. Modified PE can be degraded in aqueous solutions using commercial enzymes. Finally, turbidity tests indicate that functionalized PE are interesting candidates for biobased and enzymatically degradable dispersing agents, which can be used in washing formulations.