Use of bast fibres including flax fibres for high challenge technical textile applications. Extraction, preparation and requirements for the manufacturing of composite reinforcement fabrics and for geotextiles

Flax (Linum usitatissimum L.) has been grown since the antiquity for tis ability to provide fibres for the confection of clothes. It has also been used for the production of technical fabrics such as sails for example. In the 20th century, and particularly in Europe, the vegetal fibres such as flax were progressively replaced by synthetic fibres from petroleum origin. However, a large regain of interest for vegetal fibres and particularly for flax fibres was observed in the last two decades for using these fibres in challenging new applications for which the environmental impact is considered. Different varieties of Linum usitatissimum L.have been selected by breeder to optimise the production of fine long fibres (textile flax) or to optimise the production of seeds (linseed or oleaginous flax). In both cases, bast fibres can be extracted from the flax stems. This chapter shows that the fibres extracted from either textile or linseed flax varieties can be used for different technical textiles for high added value applications. In a first part, the chapter deals with the different processes used to extract and prepare the fibres for textile applications according to the growth and harvesting techniques considered. In a second part, different manufacturing processes or techniques to produce flax fibre non-woven and woven textiles for composite reinforcements are presented. A discussion about the interest of selecting a particular type of yarn or a particular 2D or 3D architecturation technique is also presented in relation to different composite requirements and applications. The third part of this chapter is dedicated to the interest of using flax fibres for non-woven and woven geotextile applications. Specificities associated to the use of biodegradable vegetal fibres are presented and solutions to control the degradation time of the textiles with a minimum impact on the environment are also discussed in the document