Designing every-day objects from dissolved cellulose

Abstract

Together with increased environmental concerns, the demand for substituting petroleum use with renewable resources has increased as well. Cellulose is a biodegradable, natural polymer, which is available worldwide. However, cellulose does not dissolve in water or in most common solvents. Lately, active search for green solvents for dissolution of cellulose has been focused on ionic liquids. Using ionic liquids in dissolving cellulose has increased commercial interest as well. Till now, dissolved cellulose fibers have mainly been used in textile sector, but there is enthusiasm for widening the usage of this method into other areas too.

This master thesis contains a literature review and a research project. The literature review relates to sustainability, circular economy, cellulose, textile waste and recycling possibilities of textile waste. In the research project, the aim is to explore how cellulose from textile waste dissolved into ionic liquid named 1-Ethyl-3-methylimidazolium acetate (EMIM) could be used to produce every-day decorative objects. First, I compare composites produced of traditional commercial birch pulp, those produced of cotton fibers (from a terrycloth bath towel) and those produced of cotton and lycra (from an industrially dyed and knitted sweater). After these material experiments, I perform a user study as I want to explore how composites made of dissolved cotton fibers (so-called material proposal) are received by other people. Finally, I design a flowerpot representing an above-mentioned every-day object, make a mold of it using 3D printing and produce it using dissolved cotton fibers.

According to my experiments, the flowerpot should be produced using 9 weight percent cotton fibers, which are dissolved only partially into EMIM. The mass should be coagulated within a mold in the water tank, and, further, the flowerpot should be air-dried in its mold. This way, the material is durable enough to be bent by hand, it maintains its shape, it comes off the mold effortlessly, and its surface is customizable. Further, an object made of only partially dissolved fibers is porous, and, especially in flowerpot, this trait is favorable since porous material absorbs moisture and enables air flow, which is important for soil and plant roots. Finally, an object air-dried in a mold shrinks less than an object air-dried without a mold.

From the perspective of my preliminary research findings, dissolving textile waste into ionic liquids to produce every-day decorative objects seem to have potential for further evolution.