Characteristic and Performance of Elementary Hemp Fibre

Abstract

This paper presents systematic and improved methodologies to characterize the surface and fracture of elementary hemp fibres by Field Emission Scanning Microscope (FE-SEM), determine the Microfibril Angles (MFA) by an advanced microscopy technology and examine the crystallinity by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR). The results showed that 1) There existed various deformations/defects in elementary hemp fibres, showing four types of deformations, namely kink bands, dislocations, nodes and slip planes. The crack on the surface of elementary fibres was the initial breaking point under stress; 2) Under tension the primary wall and secondary wall of hemp fibres showed different deformation and breaking behaviour. The crack initiated in a weak point of primary wall and subsequently propagated along radial direction from S1 to S2 layers; 3) The average MFA for the broken regions of S2 layer was 6.16? compared to 2.65? for the normal hemp fibres and the breaking of hemp fibres occurred at the points where had the biggest MFA; 4) The average MFA was 2.65? for S2 layer and 80.35? for S1 layer; 5) the Crystallinity Index (CI) determined by XRD and FTIR was very similar, showing the lattice parameters of the hemp fibres tested a = 6.97 Å, b = 6.26 Å, c = 11.88 Å and γ = 97.21?, and the ratio of 1423 to 896 cm-1 was found more suitable for CI evaluation for hemp fibres.