Investigation of the structure changes and properties of stretched mohair fibre

The structure changes and properties of stretched mohair fibres were studied using Raman spectroscopy, tensile tests, scanning electron microscope (SEM) and friction coefficient tests with the stretching ratios at 0%, 20%, 40% and 60%. The curve-fitting method of the amide I region implies that the conformational changes of stretched mohair fibres are mainly transformed from α-helical to β-pleated sheet structure. The tensile behaviours of the stretched mohair fibres also indicate the α → β microstructure transformation. The SEM results indicate that when the stretching ratio was 40%, the scales of stretched mohair fibres are obvious lifting of scales edges on the fibre. In contrast, when the stretching ratio was 60%, there is evidence of surface damage, with the lifted cuticle scales being chipped and flaked off. The friction coefficient of along and against scales with different stretching ratios also supports the morphology changes of scales and the presence of ‘stick–slip’ phenomenon at different friction speeds.