Fabricating lignocellulosic films as potential biobased plastics

Abstract

Replacing petroleum based plastic packaging with an environmentally sustainable and economically viable process is an important step towards the goal of displacing oil as a petrochemical feedstock. Here we report the preparation of thin films consisting only of cellulose and lignin, using a recyclable ionic liquid. A co-solvent, DMSO, was used to decrease the viscosity of the dope solutions and facilitate the dissolution of the lignin. The films exhibit high mechanical properties with the tensile strength ranging between 65.44 and 93.15 MPa, comparable to those of commercial counterparts, while the presence of lignin increases the viscosity of the dope solutions, adds UV blockage to the films and decreases the wettability of the films with the water contact angle increasing up to 48.6%. The films are stable in various solvents and when immersed in aqueous solutions can swell and double in mass. The research also confirms that the ionic liquid can be retrieved and reused for at least five cycles without hindering its chemical composition and thermal stability.