The broader impact/commercial potential of this Partnerships for Innovation-Research Partnerships (PFI-RP) project will be to transform plastics manufacturing by using lignin, a naturally occurring material, as a renewable feedstock. Plastics are a major component of many consumer products such as bottles, synthetic fibers, building materials, etc., and are currently made from petroleum resources. In recent years, many attempts have been made to produce ingredients for plastics from agricultural resources as a more sustainable feedstock. One technological challenge is the ability to handle the diversity of plant sources (grasses vs. hardwoods) as feedstocks to make consistent and compatible ingredients currently used in plastics. This work develops a technology to make plastic precursors from lignin derived from various sources, such as cellulosic ethanol plants or the pulp and paper industry. The proposed technology breaks down the lignin into smaller chemicals that are readily transformed into substances that can be used to make plastics. By demonstrating a modular technology concept, scale-up to industrial production rates is achieved by simply increasing the number of modules. The commercialization of this technology has the ability to capture a significant fraction of the related global phenolic resins market, expected to reach nearly $16 billion by 2025. Such value-added products will significantly enhance the economic viability of biorefineries.
The proposed project will address the major challenge of developing practically viable technologies to make value added products from lignin for profitable biorefineries. Specific objectives are to demonstrate a scalable technology for converting lignin from various sources (alkaline, organosolv and milled lignin) to bio-based prepolymers suitable for making resins and plastics. This is achieved by selective ozonolysis of the lignin solution (in acetic acid) in a spray reactor to partially break up the lignin into low molecular weight aromatics which are then grafted on to the macromolecular lignin structure by acidification with sulfuric acid in a stirred reactor. This technology converts >95% of the lignin to prepolymers which are separated by filtration from the solvent which is recycled. These two steps occur sequentially at mild operating conditions (ambient temperature and pressure) that favor process economics. Process optimization to form prepolymers with desired properties will be guided by benchmarking with conventional phenol-formaldehyde and bakelite-type resins. Process scalability will be demonstrated by operating multiple spray reactors in parallel followed by acidification of the combined ozonolysis product to generate prepolymers with identical properties and in sufficient quantities for product testing.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
