Yarn Flax Fibres for Polymer-Coated Sutures and Hand Layup Polymer Composite Laminates

Flax (Linum usitatissimum) is a blue-flowered herbaceous plant that widely grows in temperate zones as a source of both fibres and oil. While it is well known that flax fibres have been used for making linen, from a biomedical perspective, probably one of the more important applications of flax fibres is for making surgical sutures. In addition to employing flax fibres for polymer-coated sutures, more recently, flax fibres have been proposed for reinforcing polymer composites, such as hand layup laminated scaffolds in tissue engineering. This chapter explores the mechanics of flax fibres based on recent findings from studies conducted by the authors as well as from the literature. The focus is on the effects of moisture on the mechanical properties of yarn flax fibres as well as the possible dependence on knot geometry. The findings are applied to support arguments for the design considerations of polymer-treated flax fibre for, e.g., sutures as well as hand layup polymer composite laminates.