Fibres from Reindeer Tendons : Mechanical and retting processes for extractning collagen fibres

Abstract: Collagen fibres from reindeer tendons can be used to create threads. These threads have traditionally been used in Sápmi crafts. Due to the high cost of manual extraction, tendon-based threads have been replaced with cheaper synthetic threads. However environmental concerns have been raised within the Sápmi crafts communities regarding the synthetic threads. To mitigate the impacts of synthetic threads and to better utilize the reindeer after slaughter a more efficient fibre extraction process has been sought after. In this study two venues have been investigated, softening and retting. In this study softening will refer to the breaking of bonds through the use of a liquid. Retting will refer to a controlled degradation of a material through biological processes. Softening and retting aided mechanical extraction of collagen fibres. The softening, using water and in some cases polyethylene glycol, reduced entanglement and friction. The retting can be divided into short term retting and long-term retting, up to six weeks. Neither the short-term retting nor the long-term retting did facilitate the extraction significantly compared to a simpler softening treatment. Softening on the other hand made extraction easier. A 70 hour softening with water at room temperature had the largest impact. The extraction became slightly easier when the samples were further softened with polyethylene glycol. This was compared to a reference sample where water was used for further softening. Mechanical fibre extraction methods were also evaluated. The softened tendon samples were calendered between two rollers at 1.2 bar and 5.0 bar. The samples using the higher pressure were easier to separate. The samples were then manually torn apart into fine fibre bundles. Many of the manual methods used can be automated but they would need specialized equipment. The mechanically extracted fibres were then spun into yarns through hand spinning with moistened fingers. The tensile properties of the fibres and the yarns were determined. The fibres and the yarns were also evaluated through light microscopy. Both the yarns and fibres showed a high degree of variation in the tensile tests. The use of manual methods likely contributed to the high variation. The yarns slipped which caused a lower tenacity compared to the fibres. The mean fibre tenacities were between 17-20 cN/tex, depending on factor. Neither of the factors were significantly different. The elasticity of the fibres varied to a large extent. The fibres exhibited an almost fully elastic deformation until break. The fibres were white to cream and slightly translucent when viewed in a light microscope. The yarns were uneven and glossy.