Optimizing the alkali treatment of cellulosic Himalayan nettle fibre for reinforcement in polymer composites

Abstract

The Himalayan nettle plant can yield strong and long bast fibre. In this study, the extracted fibres were treated with 3, 5, 7, and 10 wt% alkali solution and characterised the raw and treated fibres for chemical, morphological, physical, mechanical, and thermal properties. The objective is to find the optimized alkali concentration for fibre surface treatment to use as reinforcement in polymer composites. Results revealed that alkali treatment removed waxes, lignin, and hemicellulose from the surface and enhanced the fibre properties to make it compatible with the polymer matrix. However, alkali concentration affected the fibre properties significantly. 5 % alkali treatment resulted in a maximum crystallinity index (79.1 %), average roughness (26.8 nm), tensile strength (296.97 MPa), activation energy (181.33/180.97 kJ/mol) and initial temperature for stage II degradation (311.2 °C). This investigation concludes that 5 % is the optimized alkali concentration for surface treatment of the nettle fibre.