This INSPIRE project is jointly funded by the CMMI and CBET Divisions in the ENG Directorate, OISE, and the Office of Integrative Activities. This INSPIRE research studies the processes needed to produce bio-adhesives from bio-mass (micro-algae, woody biomass, and animal manure) while simultaneously integrating environmental sustainability metrics into the design process to ensure superior mechanical properties. Considering the significant shortage of asphalt, the most accessible market for such bio-adhesives is envisioned to be asphalt market. It should be noted that the price of liquid asphalt, the adhesive which bonds stone particles together within a pavement structure, has increased dramatically within the last decade as its supplies have been shrinking significantly. Accordingly, bio-based construction adhesives which are being developed in EU and US could be a solution to reduce dependence of road construction industry on the liquid asphalt resources. In addition, production of bio-adhesives as proposed in this INSPIRE project can be a means of sequestering carbon from bio-mass waste which will be otherwise released back to the atmosphere as bio-mass gradually decays. Therefore, in contrast to natural decay of woody bio-mass which is typically considered to be carbon neutral, the bio-adhesive process is carbon negative because more than 60% of carbon from bio-mass will be trapped in the bio-adhesive. The project benefits from experience of international partners in France and the U.K., which will further enable U.S. scholars and students to be globally engaged to expedite knowledge development and promote diversity in the national workforce.
Bio-adhesives will be produced from an array of molecular species found in aforementioned bio-mass resources while simultaneously integrating environmental sustainability metrics as well as health and safety aspects. A thermochemical liquefaction process will be used, followed by solvent extraction, filtration and vacuum distillation to extract an array of molecular structures from micro-algae, woody bio-mass, and swine manure. Density functional theory and molecular dynamics simulations along with multi-scale experimental characterization will be used to identify how each specific extracted compound interacts with fused aromatic rings in asphalt. This will be reflected in alteration of their stacking via promotion of charge transfer as well as change of electron distribution in the core of the aromatic rings when exposed to specific functional groups derived from bio-mass. This will help understand the underlying interaction mechanisms which control macro level material behavior to facilitate design of bio-adhesives. Selected molecular species will be then assembled and co-polymerized to form bio-adhesives with specific physiochemical and morphological properties for use in asphalt.
