Steve Severtson is a professor in the Department of Bioproducts and Biosystems Engineering at the University of Minnesota (Twin Cities Campus). He teaches courses on the topics of surface and colloid science, materials science, and mechanics of composite materials. His current research projects include the study of wetting and adhesion involving soft substrates, characterization of small molecule migration in polymer films, and development of environmentally benign coatings and adhesives. Steve received his B.A. (chemistry major) from Augsburg College (Minneapolis, MN), M.S.M.E. from Georgia Tech. and Ph.D. from IPST, which is currently IPST at Georgia Tech. Prior to joining the faculty at the University of Minnesota, Steve spent three years working as a senior chemist for Nalco Chemical Company (Naperville, IL).
Development of Renewable and Biodegradable Monomers for Adhesive Materials
This presentation will review efforts by our group to design and commercialize the next generation of pressure-sensitive adhesive (PSA). Our current interest is in the incorporation of renewable biomass into existing commercial designs. This approach aims to use reduced amounts of petroleum-derived components to maintain performance as increased levels of biomass are incorporated into adhesive polymers. The biomass is in the form of macromonomers generated via bulk, ring-opening polymerizations of lactide and e-caprolactone with hydroxyethyl methacrylate. Generated macromonomers are copolymerized predominantly with acrylics, which are traditionally used in permanent pressure-sensitive products, using miniemulsion polymerization. Films cast from the resulting latexes are crystal clear. Testing of films indicates that performance properties meet or exceed those of commercial, water-based acrylic PSA and tack and peel properties could be further enhanced via use of readily available tackifying dispersions. Furthermore, it was found that adhesive properties could be engineered through modifications to the content, structure, and composition of the biomass macromonomers.
In addition to reviewing the general synthesis approach, properties of latexes and adhesive films and results for the structural characterization of high-biomass content adhesive polymers, the remaining challenges faced in bringing this technology to the marketplace as well as ongoing research involving similar approaches with alternative sources of biomass will be described. Also discussed will be the increasing requirements placed on pressure-sensitive products due to their content in recyclable materials such as paper and plastic bottles and desire to close their life cycle.