Novel method of preparing flame retardant cellulose-silicate fibres

Presented herein are the results of research on the preparation of a novel environment-friendly method of spinning cellulose-silicate (Cel/Si) fibres obtained from enzymatically modified a pulp which could be directly dissolved in aqueous sodium hydroxide. Fibres were formed from spinning solutions in a coagulation bath containing sodium silicate and sodium sulphate. For selected spinning conditions, test results are shown for the physical-mechanical properties of the Cel/Si fibres obtained and their relative flammability represented by the limiting oxygen index (LOI). Cel/Si fibres are characterised by a favourable LOI value reaching as high as 46.5%. The impact of zinc concentration in the spinning solution is shown, which largely contributes to the stability of the spinning process as well as to the mechanical properties of the fibre and the LOI value. The surface and cross-section of the Cel/Si fibres were inspected by scanning electron microscopy (SEM), including those subjected to high temperatures and a naked flame. It was found that the fibres reveal a skin/core structure in which zinc silicates are the main constituent of the skin, while cellulose forms the core. Also presented are test results of Cel/Si fibre washing durability. Proof is also given of the excellent antibacterial properties of the fibre against the Staphylococus aureus strain.