A comparative study of the mechanical properties of wool and alpaca fibres

This study reports the latest research into alpaca and wool fibres. In particular, those properties that have received little attention in research literature have been examined. They include single fibre abrasion and bending fatigue, single fibre tensile properties, as well as resistance to compression behaviour. These properties are important because they affect the softness and pilling propensity of these fibres and the resultant fabrics. Clean wool and alpaca fibres were used in this study. Fibre abrasion/bending fatigue measurements were carried out using a Textechno FIBRESTRESS instrument. The resistance to compression (RtC) tests were carried out according to Australian Standard AS3535-1988. The results indicate that wool and alpaca fibres behave quite differently, even though both fibre types are of animal origin. Wool fibre resistance to compression decreases as fibre diameter increases while the opposite appears to occur for alpaca fibres. For both wool and alpaca the number of abrasion/bending cycles at fibre break increases with an increase in fibre diameter, it takes longer to break the alpaca fibres. Reasons for these differences have been postulated based on differences in fibre surface and structure between alpaca and wool.

The measurement precision and evaluation of the diameter profiles of single wool fibres

A recent model of Single Fibre Analyser 3001 (SIFAN3001) was firstly employed to obtain the single wool fibre diameter profiles (SfFDP’s) at multiple orientations. The results showed that using SIFAN3001 to measure fibre diameter at four orientations for 50 single fibres randomly sub-sampled from each mid-side sample can produce average fibre diameter profiles (ASfFDP’s) of fibres within staples. Within the testing regime used, the precision estimates for the total samples were ±1.3µm for mean fibre diameter of staples and ±1.4µm for average fibre diameter of the ASfFDP’s at each scanned step in the diameter profile. The mean diameter ratio (ellipticity) obtained from the four orientations was 1.08±0.01, confirming that the Merino wool fibres under review were elliptical rather than circular. The elliptical morphology of wool fibres and the precision of fibre diameter measurement at each point along a fibre will be considered in the development of a mechanical model of Staple Strength testing.