Researcher(s)
- Robbie Witikko, Chemistry, West Chester University of Pennsylvania
- Sampanna Mhatre, , University of Delaware
- Jackie Arnold, Chemical Engineering, University of Delaware
- Alex Balzer, , University of Delaware
- Subiksha Vidya, , The Charter School of Wilmington
Faculty Mentor(s)
- Thomas Epps III, Chemical and Biomolecular Engineering and Material Science and Engineering, University of Delaware
- LaShanda Korley, Chemical and Biomolecular Engineering and Material Science and Engineering, University of Delaware
Abstract
Lignin-derivable precursors are promising renewable alternatives to petroleum-based building blocks used in polyurethane (PU) synthesis due to their reduced toxicity and their potential for improved thermomechanical performance. In an expansion of our previous studies that demonstrated the effectiveness of lignin-derivable monomers in non-isocyanate polyurethanes (NIPUs), this work explores structural effects of these monomers on molecular interactions (a) within segmented NIPUs and (b) between non-segmented PU/NIPU matrices and metal-organic framework (MOF) additives. To benchmark the structure-property effects of these renewable bio-derivable polymers, petroleum-derived controls derived from bisphenol-A (BPA)-based monomers were synthesized and characterized. A series of segmented NIPUs were formulated with amine-terminated polybutadiene-co-acrylonitrile as the soft segment and BPA cyclic carbonate with three diamine chain extenders as the hard segment. The careful selection of building blocks enabled the synthesis of phase-separated segmented NIPUs, while variation in chain extender type allowed for tunability of polymer morphology and glass transition temperatures. The influence of chain extender structures on the thermal stability and molecular weight of segmented NIPUs also was examined. Additionally, non-segmented PUs/NIPUs were designed with petroleum-derived and lignin-derivable monomers. These structures displayed varying methoxy and hydroxyl groups on the polymer backbone, which were used to establish structure-property relationships through the understanding of tensile properties and the extent of hydrogen bonding. MOFs were incorporated into these PU/NIPU materials, wherein polymer-MOF interactions will be explored to test the viability of bio-derivable PUs/NIPUs in functional coating applications. Overall, the fundamentals related to polymer morphology, thermal properties, and MOF-polymer interactions of petroleum-derived PUs/NIPUs established in this work will provide design rules for sustainable PU/NIPU composites.