Optimising the process of fibre extraction from Himalayan nettle (Girardinia diversifolia) using response surface methodology

This study investigates the effect of alkaline treatment conditions on the yield and quality of fibres extracted from Himalayan nettle bark. Process parameters are systematically optimised, revealing that fibre characteristics are highly sensitive to alkali concentration, temperature, and duration. Mild conditions result in poor fibre separation, while harsh conditions lead to fibre degradation or redeposition of impurities. Optimal conditions (8 % NaOH, 1 h, 85 °C) yield fibres with superior properties — 56.65 % yield, 1.91 tex linear density, 6.23 gf/den tenacity, 4.13 % elongation, and 204.07 gf/den modulus — significantly outperforming traditional extraction methods. The developed method is simple and can be used for large-scale extraction of nettle fibres with superior and consistent properties.