The reactivity of lingocellulosic jute fiber to sunlight (UV) and atmospheric gases and chemicals was reduced by grafting jute with acrylate monomers, such as ethyl acrylate (EA) and 2-hydroxy ethyl methacrylate (HEMA). The grafting reaction sufficiently blocked the reactive groups of jute and thus, physically- and chemically-bound cellulosic units and on the fiber surface. The grafting gave additional strength, higher thermal stability and improved surface smoothness. Though the modified fibers showed better color fastness properties in sunlight, the dyeability of the modified fibers somewhat decreased. Grafting reaction and other characteristics of modified fibers were investigated with FT-IR, tensile tester, thermogravimeric analyser, and grey scale respectively. The change of surface morphology of the jute fiber on modification was also observed with a scanning electron microscopy. Modification of bleached jute and alkali-activated bleached jute with HEMA gave higher graft yield (26.6, 29.4 %) than that of EA modification (22.5, 24.7 %). Due to the different chemical features, HEMA-modified fiber exhibited better chemical, thermal and physical properties.

Purpose The purpose of this paper is to synthesize chitosan, N-octyl chitosan (NOCh) and carboxymethyl chitosan (CMCh) derivative from prawn shell wastes and identify their applications as modifiers on cellulosic fibres, jute and cotton, to develop quality textile fibres. Design/methodology/approach Chitosan was obtained by deacetylation of chitin. NOCh was obtained by reductive amination of chitosan. Water-soluble CMCh was prepared by reacting chitosan with monochloroacetic acid in aqueous alkaline media at ambient conditions. Chitosan, NOCh and CMCh were applied on cellulosic fibres, and structure and physico-chemical characteristics of chitosan derivatives and modified fibres were investigated and analysed. Findings The molecular weight, degree of deacetylation and ash content of prepared chitosan were 1,39,958 Da, 85 and 2.33 per cent, respectively. The moisture content, water holding capacity and total nitrogen content were above 10, 450 and 6.5 per cent, respectively. Average degree of substitution of CMCh was 0.82 as determined by titrimetric analysis. Fourier transform infrared spectroscopy (FTIR) spectra showed characteristic peaks of carbonyl group at 1,659 cm−1, –NH2 at 1,600 cm−1, symmetric stretching of C-H in the methyl group at 1,520 cm−1 and carboxylic group at 1,737 cm−1. Thermograms showed moderate thermal stability in treated fibres compared to untreated fibres. Surface morphology of the modified fibres exhibited smoother surface due to the absorption of chitosan, NOCh and CMCh. Originality/value Modification of jute and cotton by sorption of NOCh and CMCh introduced new functional groups on the fibre surface with chemical bonding, which was confirmed by FTIR. Surface morphology of the fibres was carried out by scanning electron microscopy. As the modified fibres also showed good dyeability and colour fastness as well as other properties, the chitosan derivatives as a textile modifier would be helpful to avoid synthetic petroleum-based chemical modifiers as well as to manage the environmental pollution from prawn shell waste and other toxic chemicals.