SBIR Phase I: Expanding the Sustainability of Bio-plastics and PLA by Postponing End-of-Life through the use of Reactive Extrusion Chemistries

This Small Business Innovation Phase I project proposes to address the issue of end-of-life management of a family of bioplastics, specifically polylactic acid (PLA). The majority of products today manufactured from PLA are land filled or incinerated once reaching their end of life. Although PLA is a compostable bioplastic, there is a significant lack of industrial composting infrastructure in the United States. Furthermore, PLA is not typically recycled due to a significant loss of mechanical properties during reprocessing of the plastic. In the proposed work, a reactive extrusion process will be used to recycle waste PLA to produce hyperbranched PLA polymers. Hyperbranched PLA exhibits mechanical properties that are improved relative to virgin, linear PLA. The reactive extrusion process to impart hyperbranching is cost-effective and scalable, enabling a viable business to sell recycled PLA and license the process technology to other processors. The proposed research will demonstrate how both post-industrial and post-consumer waste PLA can be converted into hyperbranched PLAs having improved mechanical properties. This process will significantly enhance the value of scrap PLA, by converting a waste stream into a product. The broader impact/commercial potential of this project is the development and commercialization of an important, novel, and cost effective way to meet the pressing need of making plastics more sustainable by adding value to the most broadly used bioplastic, PLA. Creating improved mechanical property PLAs from a lower cost feedstock will ultimately expand commercial applications. The current U.S. market for PLA is approximately 300 million pounds and growing at approximately 15% annually. Commercial plastic processors that use PLA will be able to replace or supplement use of virgin PLA with recycled PLA. Additionally, by providing a commercially-attractive method to recycle PLA, this new process will effectively incentivize recyclers to remove PLA from their waste sources. The only current competitive technology for recycling PLA is to use existing polymer recycling processes without hyperbranching, but these methods are unable to provide recycled materials with useful properties. Other options for reclaiming PLA include composting and chemical recycling back to lactic acid. Both of these technologies offer a reasonable way to dispose of PLA at its end of life; however, only recycling of PLA by hyperbranching offers a way to significantly extend the end of life.