Education for Sustainable Development: An Undergraduate Chemistry Project on Cellulose Dissolution, Regeneration, and Chemical Recycling of Polycotton

Abstract

We introduced an undergraduate chemistry project within the framework of education for sustainable development (ESD). The objective of the first part was to demonstrate the efficiency of an ionic liquid (IL)- 1-(n-butyl)-3-methylimidazolium acetate (BuMeImAcO)- as solvent for the dissolution, and subsequent regeneration of cellulose as fiber. Under mechanical stirring, the students dissolved microcrystalline cellulose in a mixture of BuMeImAcO-dimethyl sulfoxide (DMSO) at 80°C. Subsequently, they dyed the dissolved cellulose with a reactive dye, and regenerated (pink) colored fibers by injecting the resulting biopolymer solution into water (a non-solvent for cellulose). The objective of the second experiment was to show the potential application of BuMeImAcO-DMSO for the chemical recycling of the cellulosic component of polycotton (cellulose: polyethylene terephthalate; PET). Cellulose dissolves under the above-mentioned experimental conditions, leaving a mat of PET. The students dyed the dissolved cellulose, and then regenerated the biopolymer as fiber. This project fits the following aspects of ESD: fiber production from renewable sources other than cotton (wood-based cellulose); recycling of cellulose from its blends with synthetic polymers, when their reuse is not feasible. We recommend this project for senior science students of, e.g., chemistry, engineering and pharmacy, because of its simplicity, safety and socioeconomic relevance.