Akiko Isa

Evaluation of Binding Effects in Wood Flour Board Containing Ligno-Cellulose Nanofibers

Wood-based materials are used extensively in residual construction worldwide. Most of the adhesives used in wood-based materials are derived from fossil resources, and some are not environmentally friendly. This study explores nanofiber technology as an alternative to such adhesives. Previous studies have shown that the three-dimensional binding effects of cellulose nanofiber (CNF), when mixed with wood flour, can significantly improve the physical and mechanical properties of wood flour board. In this study, ligno-cellulose nanofibers (LCNF) were fabricated by wet disk milling of wood flour. Composite boards of wood flour and LCNF were produced to investigate the binding effect(s) of LCNF. The fabrication of LCNF by disk milling was simple and effective, and its incorporation into wood flour board significantly enhanced the physical and mechanical properties of the board.

Binding effect of cellulose nanofibers in wood flour board

Wood-based materials are extensively used for residual construction worldwide, especially in Japan. Most wood-based materials are fabricated using adhesives, some of which are not environmentally friendly. As an alternative to chemical adhesives, we explored this issue using nanofiber technology, especially the use of cellulose nanofibers (CNF), as reinforcement in wood flour (WF) board to replace chemical adhesives. We found that CNF could be easily made by pulverization in a ball mill. The physical and mechanical properties of WF board were improved by the three-dimensional binding effects of the CNF.

Increased Water Resistance of Bamboo Flour/Polyethylene Composites

Abstract To improve the water resistance of bamboo flour/high-density polyethylene (HDPE) composites, the effects of plastic content, coupling agents, and the addition of micro-fibrillated cellulose (MFC) on formulations were studied, and their rheological and mechanical properties were evaluated. The composites were prepared by injecting molding with a basic composition of equivalent amounts of bamboo flour and HDPE, and the melting fluidity of the compounds, tensile strength, and tensile modulus of the composites were determined. An increase in water resistance was detected in all three tests. By increasing the plastic content, negative effects such as a decreased tensile modulus were observed. When evaluating the compatibility between bamboo flour and plastic using coupling agents and MFC addition, positive effects were noted for water resistance, melting fluidity, and tensile modulus. We also confirmed that the procedure used to increase the compatibility between bamboo flour and plastic could easily be used for industrial applications by changing the coupling agents. Overall, a novel positive property (increased tensile modulus) and an increased water resistance were observed after MFC addition.

The Effects of Wet-Milled Wood Flour on the Mechanical Properties of Wood Flour/Polypropylene Composites

Abstract The sizes and shapes of wet ball-milled wood flour were investigated based on their average particle size, size distribution, their solution viscosity, and scanning electron microscopy images. The ball-milling conditions were combinations of rotational speed (150, 200, and 250 rpm) and milling time (1 to 16 h). The average diameter of the wood flours decreased and the degree of fibrillation of the wood fibers increased with the ball-milling time at each rotational speed. Ball-milled wood flours having the same average particle size had similar surface fibrils that were tens to hundreds of nanometers wide. Ball-milling at 200 or 250 rpm could pulverize just as effectively as that at 150 rpm because the size reduction and fibrillation progressed more quickly. Tensile and bending properties of the composites prepared from the ball-milled wood flour (4 wt% in polypropylene) were evaluated. Morphological changes in the wood fillers had little effect on the properties of the composites. The tensile and bending properties of the composites containing the wood filler were 10% higher than those for the unfilled resin.