Green modification of natural fibres with nanocellulose

Abstract

The present paper presents a green process of two-step nanocellulose modification of hemp fibres and investigates the mechanisms of the efficacy of the modification. The results showed that the present nano-modification significantly increased the mechanical and interfacial properties of hemp fibres. The optimized condition (pH 11, 0.1% DTAB) of the nano-modification resulted in an increase of the modulus, tensile stress and tensile strain of hemp fibres by 36.13%, 72.80% and 67.69% respectively. FEG-SEM micrograph revealed that the nanocellulose modified the natural fibres in two ways, namely, nanocellulose (i) filling in the stria and (ii) bonding the inter-fibrils in the gaps between fibrils. XRD results showed the nano-modification increased the crystallinity index of natural fibres up to 38.46%. Resin absorption of the nano-modified fibres increased by 39.00%. XPS measurement and the ATR-FTIR characterization indicated that the nanocellulose modification may have resulted in changes in the chemical elements and chemical structure of interfaces, the esterification between hydroxyl groups at C-2 and C-6 of nanocellulose and carboxyl groups of the unsaturated polyester.