(291c) Renewable Polymers Via Direct Functionalization of Lignocellulosic Sugars

The development of sustainable plastics from abundant renewable feedstocks has been limited by the complexity and efficiency of their production as well as their lack of competitive material properties. Here, we demonstrate the direct transformation of the hemicellulosic fraction of non-edible biomass into a tricyclic diester plastic precursor at 83% yield (95% from commercial xylose) during integrated plant fractionation with glyoxylic acid. Melt polycondensation of the resulting diester with a range of aliphatic diols led to amorphous polyesters (M_n= 30-60 kDa), with high glass transition temperatures (72-100℃), tough mechanical properties (UTS: 63-77 MPa, E_T: 2000-2500 MPa, ε_avg: 50-80 %) and strong gas barriers (OTR_100µm: 11-24 cc.m^-2.day^-1.bar^-1, WVTR_100µm: 25-36 g.m^-².day^-1), which could be processed by injection-moulding, thermoforming, twin-screw extrusion and 3D-printing. Though standardized biodegradation studies still need to be performed, the inherently degradable nature of these materials facilitated their chemical recycling via methanolysis at 64 ℃, and eventual depolymerization in room-temperature water. Finally, we demonstrate the versatility of this diester monomer using other polymer chemistries.