Water-soluble cellulose acetate from waste cotton fabrics and the aqueous processing of all-cellulose composites

The objective of this study is to explore the possibility of using waste cotton fabrics (WCFs) as low cost feedstock for the production of value-added products. Our previous study (Tian et al., 2014) demonstrated that acidic ionic liquids (ILs) can be highly efficient catalysts for controllable synthesis of cellulose acetate (CA) due to their dual function of swelling and catalyzing. In this study, an optimized "quasi-homogeneous" process which required a small amount of acidic ILs as catalyst was developed to synthesize water-soluble CA from WCFs. The process was optimized by varying the amounts of ILs and the reaction time. The highest conversion of water-soluble CA from WCFs reached 90.8%. The structure of the obtained water-soluble CA was characterized and compared with the original WCFs. Moreover, we demonstrate for the first time that fully bio-based and transparent all-cellulose composites can be fabricated by simple aqueous blending of the obtained water-soluble CA and two kinds of nanocelluloses (cellulose nanocrystals and cellulose nanofibrils), which is attractive for the applications in disposable packaging materials, sheet coating and binders, etc.