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5937162 
Book/Book Chapter 
Strawboards bonded with urea formaldehyde resins 
Mantanis, G; Berns, J 
2001 
Washington State University Press 
Pullman, WA 
35th International particleboard/composite materials symposium proceedings 
137-144 
English 
WOS:000180356600017 
Conventional strawboard technology employing methyl di-isocyanate (MDI) binders has shown technical and economical disadvantages, specifically related to high resin costs and additional costs for release agents needed to prevent panels from sticking to press plates. Urea formaldehyde (UF) resin adhesion to straw fiber was demonstrated in a previous research project using an innovative chemi-thermo-mechanical (CTM) pretreatment of straw. This paper reports on a joint effort to develop a strawboard technology based on UF resins. Three different straw preparation systems were chosen to apply intensive shear forces to straw chips to overcome the wax and silica layer. The systems are a twin-screw extruder, a pressurized refiner, and a combined extruder-refiner treatment process. Using the first two technologies, one-layer panels exclusively bonded with UF were produced. The board characteristics included excellent appearance, surface smoothness, machinability, edge appearance, and good bending properties. The internal bond (IB) strength values achieved were comparable to particleboard standards. The swelling characteristics, however, did not meet European standards. Using the combined extruder-refiner technology, the UF bonded boards produced showed similarly excellent visual characteristics, bending and IB strength values exceeded medium density fiberboard (MDF) standards, and swelling attributes were close to reaching particleboard and MDF standards. Using UF resins to bond strawboards, manufactures can achieve good mat stability, a pressing process devoid of sticking problems, and significant cost savings. Future development work will focus on further improvement of the adhesion of straw fibers to produce still higher quality strawboards. 
Tichy, RJ; Wolcott, MP 
35th International Particleboard/Composite Materials Symposium 
Pullman, WA 
April 3-5, 2001