Effect and characterization comparison of various deep eutectic solvent types in pretreatment of lignocellulosic biomass and bioplastic production
Ga Yeon Moon, Hee Sun Youn, Ga Hee Kim, Byung Hwan Um
Abstract
The excessive consumption of fossil fuel resources is currently a significant burden on the environment. Most petrochemical plastics made from petroleum-based polymers are buried or incinerated, creating a growing need for biodegradable plastics to replace them. To address this issue, this study is aimed towards manufacturing biodegradable plastics using renewable resources like biomass and deep eutectic solvents (DES). The DES used herein vary in composition, leading to changes in their reaction with biomass. Consequently, this study highlights the comparison of the properties of biodegradable plastics prepared from DES of different compositions. After the biomass undergoes delignification using DES, lignin is regenerated into fibers through hydrogen bonding to create these bioplastics . Bioplastics made with choline chloride (ChCl)/Oxalic acid and ChCl/ZnCl 2 DES exhibit a dense structure and low water absorption because lignin is regenerated between smaller fibers by ball milling. Specifically, in the case of ChCl/ZnCl 2 , the involvement of Zn 2 + in the lignin–cellulose bond resulted in a higher tensile strength than that of other bioplastics (tensile strength: ChCl/ZnCl 2 - 2.25 MPa, ChCl/Oxalic acid, ChCl/Glycerol, and ChCl/Urea < 0.8 MPa). Additionally, in biodegradability tests, bioplastics made with ChCl/ZnCl 2 began to degrade by microorganisms after 12 weeks. The resulting biodegradable bioplastics exhibited low water absorption, high mechanical strength , and biodegradability. Therefore, this manufacturing method is promising for converting biomass into renewable value-added products using DES.