Protection of flax fiber-based yarns against natural soil degradation by chitosan

Short flax fibers, a by-product of the flax textile industry, are available in large quantities and may be considered to produce geotextiles aimed to stabilize soils. These natural fibers are particularly interesting for this kind of application because of their attractive mechanical properties and biodegradability. To improve the resistance of flax fiber-based geotextiles against natural soil degradation in order to increase their service life, different chitosan treatments were applied. Flax yarns were submitted to degradation protocols, mimicking soil biodegradation, using Aspergillus niger cellulase or Cellvibrio bacteria. It was demonstrated that low-molecular-weight chitosan acts as a physical protection preventing the degradation of amorphous and crystalline cellulose, hemicellulose and pectin. Moreover, this work shows that impregnation of flax fibers by chitosan inhibits soil cellulolytic bacteria cell growth. Thus, this article demonstrates the ability of chitosan to protect flax fibers against soil biodegradation.