Preparation, characterization and antibacterial properties of 4-aminocinnamic acid-modified cellulose fibers

Cellulose materials do not possess any inherent antibacterial properties, which greatly limits their application in medical and food packaging fields. Antibacterial cellulose-based materials offer exciting properties and functionalities. However, they are normally prepared by using unstable physically absorbed or complicated chemically grafted antibacterial agents under harsh conditions. Herein, an eco-friendly and simple strategy is performed to fabricate long-term antibacterial cellulose-based materials. Initially, cellulose fibers (CFs) were modified by sodium periodate (NaIO₄) generating dialdehyde cellulose fibers (DCFs). Afterward, the 4-aminocinnamic acid was chemically grafted onto the DCFs yielding antibacterial CFs through Schiff base reaction. The 4-aminocinnamic modified DCFs (C-DCFs) exhibited excellent antibacterial activity against S. aureus and E. coli, with inhibition ratios greater than 99.6% and 99.0%, respectively. Quite encouragingly, the C-DCFs presented long-term antibacterial effectiveness, maintaining 99% antibacterial ratio after two months of exposure to the air environment. Therefore, grafting 4-aminocinnamic acid onto the CFs endowed the CFs with robust and sustained antibacterial properties that would make the material advantageous for use in relevant applications. Our strategy is efficient, green, easy to operate both in the work-up stage and purification, in conformity to principles of green chemistry.