The amount of textile waste increases quickly every year, and most of them are disposed of through landfill or incineration, leading to numerous environmental and social issues. Cotton is one of the most utilized fibers in the textile industry, which consists of over 90% of cellulose, so waste cotton fabrics could be a useful resource of cellulosic materials. In this work, the dissolution of three typical waste cotton fabrics, t-shirt, bedsheet, and jean, in three solvent systems namely H2SO4 aqueous solution, NaOH/urea aqueous solution, and LiCl/DMAc solution was investigated. The results revealed that, compared to different types of waste cotton fabrics, the effects of three solvent systems on the dissolution of fabrics were more obvious, resulting in the significant changes in the structure and properties of regenerated cellulose films. About 2-5% of waste cotton fabrics could be rapidly dissolved (8 min) in H2SO4 and NaOH/urea aqueous solvents after the pretreatment of acid hydrolysis. At the meantime, the dissolution in LiCl/DMAc solvent did not need any pretreatment, but a lower cellulose concentration (1%), higher dissolution temperature (80 °C), and longer dissolution time (24 h) were required. After dissolution and regeneration, all the samples transformed from cellulose I to cellulose II crystals, and translucent cellulose films with smooth surfaces were successfully prepared. Among them, the films produced from bedsheet in NaOH/urea solution exhibited the highest tensile strength (76.21±8.26 MPa), thermal stability (maximum decomposition temperature of 325.66 °C), and water vapor barrier property (0.81±0.10×10-7 g m-1 h-1 Pa-1). It was because of the stronger cellulose chain entanglement and hydrogen bonds induced by the higher cellulose concentration in NaOH/urea solution. Therefore, this work proves the feasibility to recycle waste cotton fabrics into biodegradable cellulose films, which can be potentially used in various food and agricultural applications.

Recycling of waste cotton fabrics into regenerated cellulose films through three solvent systems: A comparison study

ACS Spring Meeting 2021

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