(538r) Development of Biodegradable Plastic Material from Lignin and Depolymerized Synthetic Plastic Copolymer

Plastics waste has been a concerning topic for the past decades due to its negative impacts to the environment. It is estimated that plastic production has increased approximately 6 million metric tons (MMt) which contributed to 15% greenhouse gas (GHG) emission annually (1,2). While the recycling of some types of plastic materials is more significant than others, less than 15 % of overall used plastic has been recycled in 2018 (3). The upcycling of plastic waste by introducing the biodegradable component such as lignin is recently considered as an alternate way to tackle the current plastic waste issues. Lignin is a natural biodegradable polymer that can be found in plants. There is an abundant amount of lignin produced by the paper pulping industry alone. However, it has mostly been treated as waste or only used in lower application in fuel production (4). Therefore, the objective of this research is to develop a plastic material from solely a biopolymer (lignin) and depolymerized synthetic polymer—yielding a polymer containing no virgin petrochem feedstock which is also biodegradable. Lignin oligomers will be used as the macroinitiator in the synthesis reactions to form block copolymers with polymerization of olefin monomer (a model of mixed α-olefin monomers feedstock from depolymerized plastic waste). The products from this work will be tested to determine the mechanical, thermal and rheological properties through DMA, FTIR, DSC and rheology analysis. The products will be nonlinear and mechanically too rigid/brittle due to the bulky nature of lignin and wide range polymer starting material and complex. Hence, the reduced functionalities methods such as telomerization, amination and esterification will be conducted on native lignin where a less bulky and linear lignin polymer will be obtained. Copolymerized products of reduced functionality lignin and olefin will be produced and characterized to determine the thermomechanical properties. However, the products will be more malleable and thermoformable that are suitable for replacing plastic films in single-use packaging. This research will provide useful synthesis methods and yield a biodegradable polymer material which can be a solution to the concerning plastic waste issues. Moreover, it will help promote more use of biodegradable lignin which in turn will benefit the agricultural economy.

References:

1. Geyer, R.; Jambeck, J. R.; Law, K. L., Production, Use, and Fate of All Plastics Ever Made. Science advances 2017, 3, e1700782.
2. Agenda, I. In The New Plastics Economy Rethinking the Future of Plastics, World Economic Forum, January, 2016.
3. Facts and Figures about Materials, Waste and Recycling, Plastics: Material - Specific Data, United States Environmental Protection Agency (EPA), 2018
4. Ganewatta, Mitra S., Hasala N. Lokupitiya, and Chuanbing Tang. 2019. "Lignin Biopolymers in the Age of Controlled Polymerization" Polymers 11, no. 7: 1176. https://doi.org/10.3390/polym11071176