EFFECT OF STEAM EXPLOSION AND GRINDING ON BINDERLESS BOARD MADE FROM RICE STRAW

The purpose of this study was to examine the effects of pretreatments such as steam explosion and grinding on the properties of binderless boards. Steam-exploded rice straw was ground and hot-pressed to make binderless boards. The internal bonding (IB), thickness swelling (TS) and water absorption (WA) of the boards were measured and discussed, along with the results of chemical analyses. Chemical modifications such as hemicellulose decomposition to monosaccharides and lignin reconstruction might have occurred during steam explosion, consequently increasing TB. Defibration occurred during steam explosion, causing an increase in bonding area and a reduction of the disadvantages of trichomes and protuberances that are characteristic to rice straw. Self-bonding also increased. Grinding the steam-exploded rice straw further improved TB by increasing the effective bonding area. Pretreatment combining steam explosion and grinding was the most effective way to increase self-bonding in this study. TS was also improved by steam explosion and grinding.