Synthesis and Structure-Property Characterization of Lignin-Derived Thermoplastic Poly(ether ester)s

Semi-aromatic polyesters derived from petroleum are an important class of polymers that encompass a wide variety of thermal and mechanical properties. Unfortunately, replacing the aromatic component with cost-competitive bioderived monomers is an ongoing challenge. In this presentation, we describe the synthesis of nine different polyesters made from AB monomers that can be derived from lignin, and include full characterization of their thermal, mechanical, and rheological properties. These polymers exhibit a Tg range of 16°C-65°C, tensile moduli ranging from 4.6 MPa to 1200 MPa, and elongation at break ranging from 7.5% to greater than 3800%.  All of these polymers were made at the >50 g scale and have excellent thermal stability for processing via melt extrusion. To examine the effects of structural permutations among the polymer series, we constructed master curves for seven polyesters using melt rheology. Fundamental properties such as entanglement molecular weight, packing length, and characteristic ratio are described and compared. Finally, these polyesters are demonstrated to be easily chemically recycled to monomer in high yield.