High-pressure steam: A facile strategy for the scalable fabrication of flattened bamboo biomass

Bamboo features the fastest growing speed and abundant in the plant kingdom. However, it remains a huge challenge to prepare large flat surface boards by directly sawing or cutting due to the hollow cylindrical shape of bamboo culms. We herein have demonstrated the preparation of facile scalable fabrication of larger flattened bamboo board without cutting it into arcs bamboo strips by high-press steam softening approach. The results show that modulus of elasticity (MOE) of bamboo decreases with increasing softening temperature from 100 °C to 160 °C, and increases 8.3% from 160 °C to 180 °C, which is still less than bamboo softened at 140 °C. Bamboo can be flattened after softening above 140 °C. In addition, the main components of bamboo have no obvious changes when the softening temperature is below 140 °C. Moreover, the density and MOE are reduced after softening due to the decomposition of chemical components and increases after flattening due to increasing densification of bamboo which makes the flattened bamboo structure more uniform and stable. Hemicellulose starts to decompose from 160 °C and the equilibrium moisture content (EMC) of soften bamboo is similar with flattened bamboo. It is also found that the volumetric swelling of the flattened bamboo is higher than that of soften bamboo. This work offers a facile methodology for promoting the high value-add utilization of bamboo biomass, and obtaining larger flatten bamboo board with high performance at a treatment condition of 160 ℃ and 8 min.