Poly(ester amide)s from biomass‐based 3,4‐dihydrocoumarine through Meldrum's acid mediated ketene chemistry

Abstract

AbstractMeldrum's acid mediated ketene chemistry (MAMKC) is applied to synthesis of poly(ester amide)s in this work. An MA‐functionalized phenolic amide compound (MA_PhOH‐Am) is synthesized from the reaction between a MA‐functionalized amine and 3,4‐dihydrocoumarine (DHC, a biomass‐based chemical) through amine‐lactone addition reaction. Polymerization of MA_PhOH‐Am results in the corresponding poly(ester amide) (P(Es‐Am)), through MA thermolysis reaction (generating the corresponding ketene groups) and ketene‐phenol addition reaction. Both MA_PhOH‐Am and P(Es‐Am) have been characterized with spectral methods and thermal analysis. P(Es‐Am) has an inherent viscosity of 0.49 dL g−1, a molecular weight of 76,500 Da, a glass transition temperature of 145°C (tanδ peak in dynamic mechanical analysis), a thermal stability of about 320°C, and a storage modulus at 50°C of 1.0 GPa. In the stress–strain measurement, P(Es‐Am) exhibits a Young's modulus, a tensile strength, and an elongation at break of 10.6 ± 0.7 GPa, 165 ± 40 MPa, and 1.83 ± 0.41%, respectively. An effective approach for the synthesis of high‐performance poly(ester amide)s has been demonstrated.