UCLA

This dissertation represents a broad exploration of polymer chemistry, anchored in the principles of the Circular Economy and sustainability. The work presented herein places a strong emphasis on utilizing monomers and polymers sourced from nature. We endeavor to enhance the utility of lignin-derived polymers for commercial applications by improving solubility and thermal properties, while also delving into the synthesis of aromatic-aliphatic polyesters from renewable resources. Lignin-derived poly(ether-amide)s are targeted initially, with the aim of overcoming their solubility limitations through thiol-ene reactions. By introducing small thiol-tagged molecules, the repeating double bonds are reduced, leading to increased chain flexibility and in turn, improved solubility and glass transition temperatures. We then explored the copolymerization of lignin-derived components with lactones for the synthesis of aromatic-aliphatic polyesters. Lactones, such as lactide and glycolide, are natural building blocks pervasive across nature. They were used in ring-opening polymerizations to produce aliphatic alcohol likers. The lactone linkers underwent condensation polymerizations with hydroxycinnamate dimers, creating sustainable, high molecular weight polyesters with desirable thermal properties. These approaches not only enhance the viability of polymers from biomass but also align with the ethos of sustainability by repurposing natural materials.

We then pivot to focus on the development of hydrogel wound dressings, as a biomimetic extracellular matrix. Bioinspired polymers were used to initiate redox hydrogel crosslinking, leading to hydrogels with improved biocompatibility compared to the gold standard approach (APS and TEMED). Finally, this was expanded to the development of in situ forming hydrogel wound dressings that sequester and release antibiotics, analgesics, and hemostatic agents. These hydrogels exhibited rapid formation, controlled release of therapeutic agents, and biocompatibility, addressing the acute need for hemostasis and infection prevention in traumatic blast wounds. In vivo studies demonstrated the safety and efficacy of these hydrogel wound dressings in reducing bacterial burden and promoting wound healing. Overall, this work presents a holistic approach to polymer science, drawing inspiration from nature and rooted in sustainability. By harnessing the potential of natural monomers and polymers, we seek to advance the field while addressing pressing challenges in materials science and healthcare.