Characterization of ultrasonic impact on coir, flax and hemp fibers

Ultrasonic processing appears as a promising way to modify lignocellulosic material composition. Herein, it has been used on coir, hemp and short flax fibers. The optimal degradation was obtained after 24 h of ultrasonic treatment. Fibers were only slightly degraded by ultrasounds: flax and hemp fibers underwent respectively 4.52% and 4.13% weight loss and were found less sensitive to the treatment than coir fibers which exhibited a 9.17% weight loss. Ultrasound effect on the different components of these fibers, i.e. lignin, pectins, cellulose and hemicellulose was investigated and the results obtained on fibers were confirmed using solutions of these compounds. We found that ultrasonic processing of coir, flax and hemp fibers only degraded hemicelluloses in the fibers.