Research Focus On Dr. Srikanth Pilla
Jenkins Endowed Professor
Associate Professor of Automotive Engineering
Clemson University

Enabling Partnership between South Carolina and NREL for advancing Opportunities in Plastics Recycling Research (EPSCOR for Plastics Recycling)

The feedstocks of polymer synthesis in America’s future will ensure the health and safety of those who make and use them, but also ensure the renewability and sustainability of the planet that sustains them. The global problems, and even crisis, associated with the increase of plastic waste in all environmental systems as well as the harmful industrial practices that make them call for unique and ingenious solutions to be applied on a large scale. The turn toward biomass as a feedstock renewing on the lifecycle of months and years instead of millennia is a well-founded, carbon neutral solution. However, with the early success of cellulosic ethanol and carbohydrate utilization from agricultural materials a clear absence is found for the utilization of the other 1/3 of biomass: lignin. This difficult polymer accounting for the highest abundance of natural aromatic units on earth has put barriers between researchers and industry based on difficult processing conditions, heterogeneous samples, and low reactivity. Yet, in the last decade an explosion of efforts has demonstrated impressive results in the chemical breakdown of lignin to usable starting material for polymer synthesis. The first goal of this proposal is the use of such methods to synthesize polymers that bring lignin closer to higher value applications. The breakdown of lignin to usable phenolic compounds and lower molecular weight fragments enables the efficient synthesis of high performing polymers. Using a non-toxic and biobased approach, lignin is transformed into non-isocyanate polyurethanes, epoxies, and polyamides. These materials represent an enormous portion of the yearly polymer demand finding applications in almost every sector of society: automotive, building and construction, apparel, aerospace, packaging and more.

The synthesis of sustainable polymers must be recyclable by design. The use of lignin is a starting point for recycling based on nature’s own pathway of producing materials rich in carbon-oxygen bonds. However, the functionalization scheme used here extends lignin’s natural structure with additional liable ether and carbonyl groups enhancing the capacity for breakdown of the polymer structure after curing. In a further innovation, the use of recycled PET from one-time-use bottles will be incorporated in polymer structures utilizing established procedures for the chemical recycling of this high-volume commodity plastic. The design for recyclability of these non-isocyanate polyurethanes, epoxies and polyamides from lignin will be optimized and the second-generation materials will be tested for commensurate properties. The goal is to establish a synthetic pathway for processing lignin into high performing polymers capable of reversion to chemical building blocks and re-synthesis. The success of this project aligns with DOE’s Basic Energy Science and EERE’s Bioenergy Technologies division goal to increase the use biomass in plastic production and find new ways to synthesize polymers recyclable by design. The outcome of this project supports the advancement of South Carolina as a leader in the sustainable manufacturing of plastics in world-wide demand.

Dr. Srikanth Pilla joined CU-ICAR in August 2013 as an Assistant Professor of Automotive Engineering. Prior to coming to CU-ICAR, Dr. Pilla was Assistant Scientist at the Wisconsin Institute for Discovery, University of Wisconsin-Madison. Dr. Pilla also has industrial experiences at SC Johnson and Son Inc. and SuGanit Biorenewables Inc. Dr. Pilla received his B.S. degree from JNT University India, MS from University of Toledo and PhD from University of Wisconsin-Milwaukee, all in Mechanical Engineering. He then obtained a postdoctoral training from the department of Civil and Envirnomental Engineering at Stanford University.

August 2020