The effects of cold oxygen plasma treatment on the exterior and interior surfaces and wettability of wheat straw were investigated. The wheat straw was treated with oxygen plasma for 150 s, and the radio-frequency power was set at 100 W. The surface wettability was evaluated by measuring the contact angles and the K values of urea-formaldehyde, phenol-formaldehyde, and methylene diphenyl diisocyanate resins. Specimens with different gluing surfaces were bonded together with urea-formaldehyde and phenol-formaldehyde and then hot-pressed to assess bonding strength. Results indicate that the dynamic wettability and the shear strength of wheat straw were remarkably improved after it was exposed to the cold oxygen plasma. Additionally, the adhesive type and the wheat straw surface characteristics had significant effects on the dynamic wettability and bonding strength of both untreated and plasma-treated wheat straw.

https://ojs.cnr.ncsu.edu/index.php/BioRes/article/download/BioRes_09_1_1578_Yang_Dynamic_Wettability/2597

Dynamic Wettability of Different Adhesives on Wheat Straw Surface Modified by Cold Oxygen Plasma Treatment

A thin layer of wax and inorganic silica on wheat straw surfaces has been known to be one of the major barriers in utilizing wheat straw for profitable and marketable composites.Enzyme pretreatments with Trichoderma sp.and Aspergillus niger were used in this study to improve surface wetability and bonding performance.The results showed that enzyme concentration and pretreatment duration had a significant effect on the surface bonding strength of wheat straw.Generally,higher enzyme concentration and longer pretreatment will increase the surface bonding strength.

Gao Xiang

Papers

Influence of Enzyme Pretreatment on Surface Bonding Properties of Wheat Straw