Effects of resin content and precompression treatment on bulk bamboo extrusion

The use of bamboo, as a natural fast-growing renewable natural resource, contributes to solving resource-depletion and environmental problems such as global warming. We applied a new wood-flow-forming technique to bulk bamboo impregnated with phenol formaldehyde (PF) resin in order to promote the use of bamboo. The influences of resin content and distribution in the bamboo on formability (extrudability) during lateral extrusion were investigated. Moreover, we developed a precompression treatment method during which cracks were introduced in the bamboo prior to resin impregnation, and the effects of this treatment method on the resin permeability of the bamboo were determined. The forming pressure during extrusion decreased linearly with increasing PF-resin content, and this tendency was independent of the presence of cracks or the distribution of the resin. Therefore, increasing the resin content of the bamboo is important for improving the extrudability of bulk bamboo. Precompression treatment was found to effectively improve resin permeability and the formability of bulk bamboo impregnated with PF resin.