Improvement of the water repellency, dimensional stability, and biological resistance of bamboo‐based fiber reinforced composites

In this study, a novel composite was fabricated based on phenol‐formaldehyde (PF) resin and bamboo fiber bundles. Various characterization techniques including fluorescence microscope, scanning electron microscopy coupled with energy‐dispersive X‐ray, and transmission electron microscope were used to investigate the distribution of fibers and infiltration of PF resin. The water repellency, dimensional stability, and decay resistance against both white‐rot ( Trametes versicolor ) and brown‐rot ( Gloeophyllum trabeum ) of the composites were also tested. The results showed that the resin not only deposited on the fibers surface, but also entered into the cellular wall and cell lumina through the pits. A great amount of resin was found in cracks and middle lamella of cell wall in resin impregnated bamboo fiber bundles owing to the mechanical defibering process. After thermal compressing, the bamboo cells were densified. The resin was redistributed in cell lumen and glue‐joints were formed. Some chemical reactions occurred between PF and bamboo by formation of aromatic esters and ether bonds, and the ether bonds were dominant. Thus, significant improvements in water repellency, dimensional stability, and biological resistance were achieved. These results suggested the composites can be used in exterior applications where high levels of water repellency and fungi resistance were required. POLYM. COMPOS., 40:506–513, 2019. © 2017 Society of Plastics Engineers