Wettability changes of wheat straw treated with chemicals and enzymes

A study was conducted to test wettability changes of the wheat straw treated with different methods for the preparation of wheat straw particle board. The wheat straws were separately sprayed with two chemicals (0.6% NaOH, 0.3% H₂O₂) and three enzymes (lipase, xylanase, cellulase). The contact angle between water and the surface of wheat straw was measured and the spreading-penetration parameters (K-values) were also calculated with wetting model. The surfaces of treated wheat straw and control sample were scanned by means of Micro-FTIR, and their peaks arrangements were analyzed. The surface morphologies of treated wheat straw and control sample were also observed by SEM. Chemical etching was found on the exterior surfaces of the straws treated separately with 0.6% NaOH and 0.3% H₂O₂; furthermore, the spreading-penetration parameters (K-values) of the distilled water on the exterior surfaces of the treated wheat straw along the grain were higher than that of control. The wettability of exterior surfaces of the wheat straws treated separately with lipase, xylanase and cellulose were improved after treating for seven days, and among the three enzymes treatments, the lipase treatment showed best result. The lipase treatment and NaOH treatment were determined as better methods for improving the wettability of wheat straw surfaces. However, in the economic aspect, NaOH treatment was more practical and easier in the pretreatment for the manufacture of straw particle board.