Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
School of Mechanical and Materials Engineering
Non Technical Summary
Polyurethanes (PUs) are widely used in products for transportation, construction, furniture, and packaging, with global production exceeding 25 million metric tons annually. The PU market continues to grow, but nearly all PUs are made from petroleum-based polyols and isocyanates. While some vegetable oil-derived polyols have begun to replace petrochemical ones in niche foam products, other biobased polyols remain in the research phase. The main challenge is that these biobased polyols do not closely resemble commercial polyols, making them less effective substitutes.Additionally, exposure to isocyanates during manufacturing of PUs and residual isocyanates in finished products can cause serious health issues, including occupational asthma, skin irritation, and respiratory problems. Some isocyanates are even suspected carcinogens. Furthermore, most commercial PUs are thermosetting polymers made with traditional isocyanate PU technologies, making them difficult to recycle. As a result, PU waste is accumulating in landfills, contributing to environmental problems.There is a clear need to innovate the structural design of new PU materials from renewable resources that are competitive in both performance and cost, meet diverse application needs, and are recyclable. Developing such a technology is crucial for addressing plastic pollution and supporting the transition to circular economy, in line with federal initiatives from agencies like the USDA, DOE, EPA and NSF.In this project, we aim to create high-performance, easily recyclable, non-isocyanate polyurethanes (NIPUs) using renewable feedstocks. Our approach involves mimicking the structural design of conventional PUs to produce renewable alternatives and incorporating easily cleavable bonds for enhanced chemical and physical recyclability. We will use tannin derived gallic acid and lignin derived vanillin and guaiacol as renewable feedstocks to prepare cleavable acetal-containing polyamines as rigid building blocks, and renewable polyols to create flexible linear cyclic carbonate prepolymers as soft building blocks. These building blocks will be combined to synthesize NIPUs that can be used in recyclable elastomers and foams.
Animal Health Component
25%
Research Effort Categories
Basic
50%
Applied
25%
Developmental
25%
Goals / Objectives
We propose to investigate the preparation of new biobased high-performance non-isocyanate polyurethanes (NIPUs) using renewable cyclic carbonates and polyamines and evaluate their applications as recyclable elastomers and foams. Our approach is to imitate the structural design of conventional PUs in preparing renewable analogues. We will use lignin/tannin derived monomers as renewable feedstocks to prepare aromatic acetal-containing polyamines (ACPAs) as rigid building blocks, and use renewable polyols to prepare flexible cyclic carbonate functionalized prepolymers (CCFPs) as soft building blocks for the synthesis of NIPUs.The long-term goal of this project is to develop a biobased NIPU system than can substitute some current petrochemical PUs in foam and elastomer applications, with competitive cost and performance, as well as inherent recyclability. The overall objective of this project is to determine the structure-composition-property relationship of the intended NIPUs and demonstrate their potential applications.To objectively test the central hypotheses and accomplish the objectives of this project, we will pursue the following specific aims:(1) Synthesize ACPAs and CCFPs from renewable feedstocks(2) Investigate the curing behavior of NIPUs and their foamability(3) Investigate the structure-composition-property relationship of NIPUs and demonstrate their potential applications as recyclable elastomers and foamsThe proposed research is creative and original, as similar NIPUs with dual dynamic networks and intrinsic repairability and recyclability have not been reported in the literature. It capitalizes on our recent findings on lignin valorization, vitrimer chemistry, recyclable PUs and vegetable oil-derived NIPUs.
Project Methods
Green and recyclable polyurethanes will be prepared by incorporating dynamic covalent chemistry in the reaction of biobased hard and soft segments, mimicking the structural design of conventional polyurethanes. Unlike conventional polyurethanes that involve moisture-sensitive and toxic isocyanates, the biobased counterparts will be prepared through carbon dioxide fixation and subsequent reaction with biobased and dynamic bond-functionalized amines. The performance (e.g., tensile strength and elasticity) of the biobased isocyanate-free polyurethanes will be compared to, and be at least 90% of, that of commercial polyurethanes.We will disseminate the research results to both industry and academia through journal publications and presentations at professional conferences. Additionally, we will seek to transfer the technologies developed in this project to polyurethane manufacturers with the assistance of the WSU Technology Transfer Office and the Washington Technology Center, a state government agency that supports Washington-based companies in technology development.