Influences of moisture content on the catalysis of sulfur dioxide and attainable properties in a vapor-phase treatment of wood with formaldehyde
2005
Iwamoto, S. (Kyoto Prefectural Univ. (Japan)) | Minato, K.
Influences of moisture content on the catalysis of sulfur dioxide and physical properties of reaction products were examined for a vapor-phase treatment of spruce wood with formaldehyde. The reaction rate was strongly dependent on the amounts of water and sulfur dioxide in the reaction system, and this was consistent with a proposal that the hydroxymethylsulfonic acid (HOCH sub(2)SO sub(3)H) formed from sulfur dioxide, water, and formaldehyde acts as a catalyst for the reaction. However, not all water molecules contributed to the formation of HOCH sub(3) SO sub(3) H, because some were adsorbed by the wood components. When the initial moisture content was high, polymeric cross-linking was likely because the ultimate weight gain was much greater than the value estimated based on monomelic cross-links. The lower values of antiswelling efficiency and higher equilibrium moisture content at a specific level of weight gain also suggested the existence of polymeric cross-links. However, the difference in the length of cross-links did not significantly influence the mechanical properties.
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