Totally-green cellulosic fiber with prominent sustained antibacterial and antiviral properties for potential use in spunlaced non-woven fabric production.

The worldwide spread of COVID-19 has put a higher requirement for personal medical protective clothing, developing protective clothing with sustained antibacterial and antiviral performance is the priority for safe and sustaining application. For this purpose, we develop a novel cellulose based material with sustained antibacterial and antiviral properties. In the proposed method, the chitosan oligosaccharide (COS) was subjected to a guanylation reaction with dicyandiamide in the presence of Scandium (III) triflate; because of the relatively lower molecular weight and water solubility of the COS, GCOS (guanylated chitosan oligosaccharide) with high substitution degree (DS) could be successfully synthetized without acid application. In this instance, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the GCOS were only 1/8 and 1/4 of that of COS. The introduction of GCOS onto the fiber endowed the fiber with extremely high antibacterial and antiviral performance, showing 100% bacteriostatic rate against Staphylococcus aureus and Escherichia coli and 99.48% virus load reduction of bacteriophage MS2. More importantly, the GCOS modified cellulosic fibers (GCOS-CFs) exhibit excellent sustained antibacterial and antiviral properties; namely, 30 washing cycles had negligible effect on the bacteriostatic rate (100%) and inhibition rate of bacteriophage MS2 (99.0%). Moreover, the paper prepared from the GCOS-CFs still exhibited prominent antibacterial and antiviral activity; inferring that the sheeting forming, press, and drying process have almost no effect on the antibacterial and antiviral performances. The insensitive of antibacterial and antiviral activity to water washing (spunlace) and heat (drying) make the GCOS-CFs a potential material applicable in the spunlaced non-woven fabric production.

Antibacterial and antiviral chitosan oligosaccharide modified cellulosic fibers with durability against washing and long-acting activity.

The worldwide outbreak of SARS-CoV-2 has attracted extensive attention to antibacterial and antivirus materials. Cellulose is the most potential candidate for the preparation of green, environmentally friendly antibacterial and antiviral materials. Herein, modified cellulosic fibers with sustained antibacterial and antiviral performance was prepared by introducing chitosan oligosaccharide onto the fibers. The two-step method is proved to be more effective than the one-step method for enhanced chitosan oligosaccharide loadings and antibacterial and antiviral activity. In this instance, the modified fibers with 61.77 mg/g chitosan oligosaccharide loadings can inhibit Staphylococcus aureus and Escherichia coli by 100 % after contacting with bacteria for 12 h and reduce the bacteriophage MS2 by 99.19 % after 1 h of contact. More importantly, the modified fibers have washing durable antibacterial and antiviral activity; the modified fibers have 100 % antibacterial and 98.38 % antiviral activity after 20 washing cycles. Benefiting from the excellent performance of the individual fibers, the paper prepared from the modified fibers show great antibacterial (100 %) and antiviral performance (99.01 %) and comparable mechanical strength. The modified fibers have potential applications in the manufacture of protective clothing and protective hygiene products.