Biobased Transparent Thiol-Ene Polymer Networks from Levoglucosan

Developing thermosets from renewable feedstocks for the production of sustainable polymer networks is of great significance as the world transitions from its heavy reliance on petroleum-derived polymeric materials. Levoglucosan is a renewable chemical, obtained from the pyrolysis of cellulosic biomass and was selected for this study due to its rich functionality. Allyl and pentenoyl levoglucosan monomers were synthesized with selective chemical functionality and were rapidly cured via ultraviolet (UV)-initiated thiol-ene click chemistry to obtain optically transparent, degradable networks. The mechanical properties (tensile strength and Young's modulus) and glass-transition temperature are tunable over the range of 1.08-3.40, 2.50-4.72 MPa, and 3.93-22.8 C-degrees based on the monomer compositions. The resulting thermosets are able to be tailored for desired properties and applications, as demonstrated by stereolithography (SLA) three-dimensional (3D) printing and postcuring modification.