Plant-Derived Materials to Enhance the Performance of Polyurethane MaterialsEPA Grant Number: R831436
Title: Plant-Derived Materials to Enhance the Performance of Polyurethane Materials
Investigators: Nelson, Chad , Hsu, Shaw Ling
Institution: University of Massachusetts - Amherst
EPA Project Officer: Richards, April
Project Period: January 5, 2004 through July 4, 2007
Project Amount: $350,000
RFA: Technology for a Sustainable Environment (2003) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
American demand (about 35% of world demand) for polyurethane foams, elastomers, coatings and adhesives currently exceeds 6 billion pounds/year and is increasing. Typical urethanes consist of diisocyanate, diol or amine extenders, and end-functionalized soft segments. Close to 2 billion lbs of aromatic isocyanates are used annually in the production of polyurethane. The aromatic isocyanates methylenebis(phenylisocyanate) (MDI) and toluenediisocyanate (TDI) are potentially hazardous, reactive materials that have acute toxicity and suspected carcigenicity that are covered under the Federal Toxic Release Inventory (TRI), and there use is subject to regulation under CERCLA and CAA. TDI waste is also regulated as hazardous under RCRA and appears in the list of chemicals that EPA determined met the OSHA criteria for the 0.1 percent de minimus limitation under section 313. To achieve the final product properties and/or optimize processing conditions, excess isocyanates are often required, resulting excess consumption and unreacted material in the final product. The rising costs of synthetic polyester and other petroleum derived additives and co-monomers are also driving up the cost of polyurethane.
The proposed project will identify new polyurethane formulations that will eliminate the need for excess isocyanates and improve the performance of the resulting polyurethane products. These new formulations will be based on new polyurethane soft segments and blends based on renewable, plant-derived materials.
Nature has provided us with an abundant supply of renewable resources to be used as raw materials. Poly(lactic acids) (PLAs), poly(hydroxy alkonate) (PHAs), and lignin all have their own unique properties that could make them suitable as additives in various types of polyurethane formulations. Poly(lactic acids) are already being produced from non-food crop residues such as corn stover. Poly(hydroxy alkonates) have been produced from plant crops such as switch grass. The use of tailored, plant-derived polyesters or polyacids can produce high performance polyurethane materials while at the same time reducing the amount of isocyanate required and eliminating the need for petroleum-derived, polyester additives. Petroleum-derived polyesters are currently used to enhance polymer performance by, among other things, modifying the crystallization behavior. The natural polyesters proposed, actually provide greater flexibility in modifying performance than the petroleum-derived counterparts. The presence of multiple reactive functional groups enables the use of lignin as a co-polymer or as an extender which has the potential to reduce the requirement for both isocyanate and diol extender. For the development of these renewable resource additives to be successful, fundamental understanding of the underlying chemistry, physical properties of the pre-polymer, curing dynamics, and morphology of the cured polyurethane is required. We will systematically study the chemical composition as well as the miscibility of the new additives. We will also measure the detailed properties of the resulting polyurethane materials.
This project will begin to develop a 'tool kit' of plant-based additives that can be used to tailor the properties of the resulting polymer to fit a variety of high performance applications. The use of tailored materials along with increased understanding of the curing process will result in polyurethane materials with enhanced performance, at lower cost, and with a lower demand for toxic and/or non-renewable starting materials. While this project will not decrease the growing world demand for polyurethane materials and products, it will, if successful, reduce the demand for aromatic diisocyanates and other, petroleum-derived starting materials and substantially reduce the amounts of unreacted isocyanates in the final product. These reductions will, in turn, reduce the risk of human exposure to these materials during the production, use, and ultimate disposal of polyurethane foams, adhesives, and coatings. The reduced demand will also reduce the quantity of aromatic diisocyanate that needs to be transported and/or stockpiled, thereby reducing the risk of accidental release to the environment.