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1960468 
Journal Article 
Agri-materials for panel products: A technical assessment of their viability 
Hague, J; Mclauchlin, A; Quinney, R 
1998 
151-159 
WOS:000084551000019 
A range of agri-materials, comprised of both potential fiber crops and existing by-products from agriculture, were investigated for their suitability as raw materials for urea-formaldehyde (UF) bonded particleboard and medium density fiberboard (MDF). Only short rotation coppice (SRC) poplar showed promise as a direct substitute for wood in particleboard. The inclusion of other materials in particleboard furnish resulted in serious reductions in product properties, in particular, internal bond strength and resistance to thickness swelling. It was shown that the adverse effects of these materials on board properties could be attributed to a range of factors. The pH and acid buffering capacity of aqueous extracts from the materials were significantly higher than those of softwoods, and in the presence of the materials, resin gel times were shown to be significantly increased. Wax occurring naturally on the surfaces of wheat straw particles was also shown to be detrimental. The presence of bast fibers in furnish derived from the 'long' fiber crop materials, e.g., flax and hemp was also shown to be detrimental due to the problems these caused during resin blending. Particleboard made with methyl di-isocyanate (MDI) resin showed improved properties, although it was evident that control of particle size was important in order to optimize panel properties. In contrast to particleboard, all materials investigated showed potential as substitutes for wood in MDF, particularly at low (20%) levels of substitution. Compared to particleboard, the improved behavior of straw used in MDF is likely to be facilitated by the break-down to fiber and fiber bundles that mix well with wood fibers. Any wax present in the straw is evenly distributed throughout the furnish. Also, the process clearly affects the fiber chemistry-refined wheat straw fiber had little effect on resin gel time in contrast to the straw itself. While none of the materials studied appeared to offer distinct advantages over wood as a raw material, in terms of either processing or product properties, it is feasible that their use might add an environmental "premium" to the value of the product.