Rheological Properties of Chemically Modified Wood: Relationship Between Dimensional and Creep Stability
Keywords:Rheology, creep, dimensional stability, chemical modification
AbstractA typology of chemical modifications of wood based on the interaction of water with the molecular constituents of the lignocellulosic material is proposed. The model accounts for both the moisture expansion and the so-called mechanosorptive creep induced by moisture changes under load. Anti-creep efficiency (ACE) values were obtained for wood specimens modified with fourteen different types of chemical treatments and subjected to a 4-day creep-recovery test under cyclic humidity conditions. The relationship between dimensional stability, as measured by anti-swelling efficiency (ASE), and ACE was determined for the different treatments. Treatments such as polyethylene glycol impregnation or etherification with epoxides, in which the hydrophilic nature of the bulking agent is not counter-balanced by crosslinking, yielded high ASE values but increased mechanosorptive creep instead of reducing it.
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