Effect of enzymes on the scouring and bleaching properties of flax roves in supercritical CO2

Supercritical CO 2 (SC-CO 2 ) scouring and bleaching of flax roves was developed by using enzymes instead of chemical additives. Effect of dosage of enzyme, enzyme ratio, temperature, pressure, time and CO 2 flowrate on the scouring and bleaching properties of flax roves was investigated. The results showed that the whiteness and residual gum content were significantly improved under appropriate conditions. Scouring and bleaching of flax roves by SC-CO 2 in combination with compound enzymes consisting of cellulose, xylanase and glucose oxidase could increase whiteness and reduce residual gum content. Moreover, glucose oxidase catalyzes the oxidation of β- d -glucose to produce H 2 O 2 , leading to the bleaching of fibers. An optimized scouring and bleaching of flax roves in SC-CO 2 was recommended at 50 °C and 15 MPa for 60 min with a dosage of enzyme of 3% (% weight of flax roves), an enzyme ratio (in mass) of 1:2:1 (cellulase: xylanase: glucose oxidase) and a CO 2 flowrate of 30 g/min. SEM displays more vertical grooves and bulges appeared on the fiber surface. The breaking strength and elongation at break of the samples were improved with the variation of scouring and bleaching conditions in comparison with the original flax roves.