Adhesion thermally treated wood

In general, properties such as colour, natural durability and dimensional stability of thermal treated wood differ from those of untreated wood. Depending on the duration and the power of the process, thermally treated wood shows improved rot-resistance properties and also demonstrates increased resistance to both fungi and climatic influences.To warrant the natural durability it must be ensured, however, that the TMT products have no contact to the ground. Furthermore, its dimensional stability can be improved as well as its adhesion property against hydrophobic materials. 

Strength of the glueline for EPI adhesives significantly. All thermally-treated posts or posts glued with thermally-treated wood produced lower shear strength than untreated wood, independent of the adhesive system used for gluing. The results in this study show why it is not recommended to use thermally-treated wood for load-bearing constructions. 

The book opens with a paper on the structure and composition of wood to define the material under discussion and then considers molds, permeability, wood preservation, thermal deterioration and fire retard-ance, dimensional stability, adhesion, reconstituted wood boards such as fiberboard and particleboard, plywood, laminated beams, wood finishes, wood-polymer composites, and wood softening and forming. A final paper treats the common theme of wastewater management. Only one of the papers presented at the meeting is not included in this volume, and its subject of conventional wood preservation methods is adequately treated in detail elsewhere (e.g., Nicholas, D. D., Ed Wood Deterioration and Its Prevention by Preservative Treatments, 2 vols., Syracuse University Press, 1973). 

The largest and oldest chemical intermediate use for methanol is formaldehyde. Over half of the methanol currently consumed in the world goes into formaldehyde production. Formaldehyde is produced by the catalytic oxidation or the oxidative dehydrogenation of methanol The major outlet for formaldehyde is amino and phenolic resins. These resins are in turn used in the manufacture of adhesives for wood products, molding compounds, binders for thermal insulation and foundry resins. Formaldehyde is also consumed in the production of acetal resins, pentaerythritol, neopentyl glycol, trimethylolpropane, methylenediphenyldiisocyanate (MDI), and textile treating resins. 

Although WLs due to biological attack decreased in treated MDF blocks, the results were unsatisfactory when compared with those of solid wood (Tables 5 and 6). Excessive reaction time (24 h) caused a rather detrimental effect on dimensional stability and on biological resistance of treated boards. This can possibly be explained by a thermal degradation of urea-formaldehyde resin as an adhesive. 

Under TG and DSC, TPF resin showed good thermal stability together with curing characteristics similar to those of the original PF adhesive. Similar DSC experiments were performed on a commercial phenol-formaldehyde adhesive plus Southern pine Pirns sp.) sap wood treated with a chromated copper arsenate (CCA) preservative [63], The thermograms indicated that curing can be accelerated at lower temperatures than normal depending upon the state of CCA in the wood. 

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