Facile fabrication of high-strength whole cotton-based cellulose film and its freshness preservation

Current studies have shown the potential of cellulose-based films in freshness preservation but are restricted by shrinkage due to the intramolecular and intermolecular hydrogen bonds in the regeneration process. The route that can consume hydroxyl groups is proper for fabricating cellulose-based film with flat appearances, such as the Schiff reaction that was the further crosslinking with polyamines. However, dynamic Schiff reaction undoubtedly releases amine components under acidic or alkaline conditions, as well as the presence of the microorganisms. Here, an acetalization was introduced to prepare a whole cellulose-based film (ORC) from cellulose dialdehyde by heat-pressing, which avoided the usage of polyamines. The resultant film presented an excellent tensile strength of above 150 MPa with an elongation at break of 2.91 %, which was enhanced by 1862 % and 191 % compared with the regenerated cellulose film (RC). Also, the ORC has shown an improved water contact angle (68 o ) and decreased swelling ratio (70 %) compared with that of the RC. It also presented a better fresh-keeping effect than the RC and PE films. The results from enzymatic and microbial degradations presented the long-term utilization of ORC. Overall, the present study provided a facile route to prepare cellulose aldehyde-derived film, and this method can be generalized to the cellulose dialdehyde/polyol hybrid films.