Fabricating of flame retardant and antibacterial lyocell fabric based on thiamine pyrophosphate modification

To improve the flame retardant and antibacterial properties of lyocell samples, thiamine pyrophosphate (TPP), a kind of water-soluble vitamin derivative, was selected for the modification of lyocell fabric. Vertical burning test showed that the combustion of treated lyocell fabric was greatly reduced. The thermal stability and char-forming ability of the treated lyocell fabric were significantly improved whether in air or nitrogen atmosphere. The char residue of flame retardant lyocell sample was significantly increased from 4.9 wt% of the control sample to 25.9 wt% in air atmosphere, and Raman spectroscopy confirmed the formation of graphitic carbon. The total heat release (THR) and peak heat release rate (PHRR) of the treated lyocell fabric decreased by 80.4% and 90.4%. In addition, the limiting oxygen index (LOI) values of the washed samples increased from 18.0% of the original sample to 28.3% even after 40 laundering cycles (LCs), demonstrating excellent durable flame retardancy. The flame retardant mechanism was explored by thermogravimetry-Fourier transform infrared spectrometry (TG-IR), thermogravimetry-mass spectrometry (TG-MS) and Raman spectroscopy. Furthermore, the treated lyocell sample had good antibacterial performance to E. coli and S. aureus. This research indicates that TPP is an effective and potential intumescent flame retardant and antibacterial agent, which simultaneously endows lyocell fabric with multifunctional properties.