Effect of Water-soluble Components Mass on the Fluidity of the Steam-treated Bamboo Powder Caused by Heating and Compression

Abstract

In this study, the effect of water-soluble components on the thermal fluidity of steam-treated bamboo powder was investigated. Bamboo powders were steam-treated at 180 or 200 °C for various steam treatment times. The bamboo powders were then treated with hot water to extract the water-soluble components. The flow rates of steam-treated bamboo powders that were either treated with hot water or not treated were measured using a capillary rheometer. In addition, thermogravimetry (TG) was also used to examine the differences in the thermal characteristics of bamboo powder treated by hot water extraction. The experimental results indicated that the quantity of hot water extract varied with the steam treatment temperature and time. Flow tests showed that bamboo powders not treated with hot water flowed, whereas those treated with hot water did not flow. The flow behavior and flow rate of the untreated powder became stable and high with an increase in the steam treatment time for steam treatment at 180 °C. For steam treatment at 200 °C, the flow behavior was more stable, and the flow rate became the highest by short time steam treatment. TG measurement of the powders suggested that water-soluble contains many volatile components, and the amount of volatile components changed along with the denaturation of the water soluble components. From these results, it was confirmed that not only the quantity of the water-soluble components but also denaturation of the water soluble component affects the thermal fluidity of the steam-treated bamboo powder.

Deep Container Fabrication by Forging with High- and Low-Density Wood

“…It is considered that this weight reduction occurred as any components volatilized with any chemical changes. This chemical change was suggested to possibly affect the flowability of the wood in the previous study [28]. The difference in W between ulin and Japanese cedar was also small.…”

“…According to a previous study [29], hemicellulose is a polysaccharide with a dry thermo-softening temperature of 167 to 217 • C. In particular, the flow of wood-based materials is affected by the hydrolysis of hemicellulose in addition to the softening of lignin. At 160 to 200 • C, the hydrolysis of hemicellulose is more active at higher temperatures, and the decomposition produces low molecular weight sugars [28]. In this temperature range, the sugars are fluid, which is thought to facilitate the generation of flow deformation, such as sliding between the fibers.…”

Effect of Heating at Oven-Dry State on Steam Treated Bamboo Powder Thermal Fluidity

“…As shown in Figures 5 and 8, = 200 ∘ C powder flow starts early compared to the other steam treatment temperatures and mass change begins at a lower rheometer temperature. It was reported that chemical changes associated with component volatilization relate with woody material thermal fluidity [13,19]. It was determined that = 200 ∘ C powder fluidity was adequately activated during the 5 min dry-heating.…”

“…In addition, it was reported that thermal fluidity and self-adhesiveness could be improved by steam treatment [7][8][9][10]. It is considered that these woody properties changes occur due to water soluble components increasing with the hydrolysis of the materials chemical components, such as hemicellulose, during steam treatment [11][12][13]. Injection molding is possible without water by using steam treated woody powder, and strength of injection molded product came up to that of polypropylene [14,15].…”

Fabrication of naturally derived wood products by thermal flow molding of wood powder with sucrose and citric acid

“…In this process, the wood powder flows with water under high temperature and pressure and becomes self-bonded when the powder is cooled. This is because the binder consists of low-molecular-weight sugars, which are generated by hydrolysis of wood components under high temperature and pressure with water (Kajikawa and Iizuka 2015). However, molding defects occur easily when wood powder is injection molded without plastic because the thermal fluidity of the wood powder is lower compared to that of the wood powder with plastic.…”