Consolidated wood

Phenol formaldehyde resin (Bakelite) 1906 1909 Enamels, moulding materials, jewellery, paints, consolidants Wood flour ... 

Characteristics of Consolidated Wood. Consolidation introduces new materials to the artifact profile, materials that have their own stability characteristics. Thus, a consolidated artifact often acquires complex behavioral alterations. Subtle and gross alterations imbue characteristics that must be anticipated. 

PEG-Treated Wood. Wood treated with PEG will also have modified gluing properties, although, if properly redried, not as much so as heavily consolidated wood. The use of PEG as a dimensional stabilization treatment was developed in the 1950s (20) and it has been used on a limited scale since then. The utility of PEG treatment for waterlogged archaeological wood is now widely recognized, and it is quite possible that some of the wood so treated has been or will need to be glued. 

Applications - brake linings, composites, foundry, mortar cements, refractory materials, sand and soil consolidation, wood modification ... 

Each chapter is designed to provide the content of a 50-minute lecture. Each block of four or so chapters is backed up by a set of Case Studies, which illustrate and consolidate the material they contain. There are special sections on design, and on such materials as wood, cement and concrete. And there are problems for the student at the end of each chapter for which worked solutions can be obtained separately, from the publisher. In order to ease the teaching of phase diagrams (often a difficult topic for engineering students) we have included a programmed-learning text which has proved helpful for our own students. 

Most ancient wooden objects recovered in archaeological excavations are usually in a decayed, weak, and friable condition that requires stabilization before the objects can be safely handled and studied. Stabilization of wood and decayed wooden objects, generally includes the use of consolidants, liquid solutions of a resin that impregnates and fills gaps in the wood and on drying solidifies, strengthening its fragile, deteriorated structure (Thompson 1991 Rowell and Barbour 1990). 

Rozman etal. (1997b) reacted wood flour with maleic anhydride (MA) and mixed the modified wood with diallyl phthalate in the presence of BPO. The mixture was then hot-pressed to form well-consolidated boards. Reaction of the wood resulted in significant increases in MOE, MOR and impact toughness of boards, compared to composites made from unmodified wood flour. It was considered that the improved properties arose due to the grafting of the diallyl phthalate monomers on to the double bond of the covalently linked maleic moieties (Figure 6.5). 

Magnetic resonance imaging (MRI) has been applied to the study of the distribution of fluid components (i.e., water or a polymer used as consolidant) in a porous material such as stone or waterlogged wood by a direct visualization of the water or fluid confined in the opaque porous medium [13]. 

After the wood particles are coated with resin, the particles are uniformly distributed into a board by an air laid process. The art of the process is in controlling and getting a uniform distribution of the wood particles by blowing them out onto a collection chain. After forming the board shape it is moved to hot presses where the wood particles are consolidated and the resin cured. From the hot presses the boards move to trim saws where the boards are cut square to their final size. In some cases, the boards are sanded to final thickness and surface smoothness. 

All of the chemical evidence that can be marshalled indicates that wood fiberboard manufacture exploits the thermoplastic properties of lignin. Defibering is effected by the thermal softening of lignin in the middle lamella at saturated steam pressures above 130C. Interfelted fiber mats are consolidated with or without densification pressure by the thermoplastic fusion of lignin-rich fiber surfaces at high board conversion temperatures. 

The major chemical changes in wood caused by fiberboard manufacture are secondary side reactions which are both beneficial and detrimental to the final properties achieved. Defibering is accomplished by hydrolytic breakdown of lignin and hemicelluloses under wet acidic conditions combined with high process temperatures. Board conversion and consolidation is attended by pyrolytic reactions which... 

Many wood species, both hardwoods and softwoods, are used for particleboard however, the density of the particleboard should be higher than the density of the raw material to efficiently utilize the adhesive system. The compression of the particles, which is required for consolidation into the finished product, enhances the particle-particle contact, producing more inter-particle adhesive bonds as well as reducing the total void volume in the panel. With wood of density higher than the finished particleboard, the compression of the particles is lower and the resultant reduced interparticle contact and higher void volume adversely influence the physical and mechanical properties of the parti cleboard. 

Decorative laminate is defined in ISO 472 but in common usage has come to mean sheet materials consisting of decorative surface papers impregnated with melamine resin and consolidated under heat and pressure with plies of core paper permeated with phenolic resin. In a wider sense the term can be applied to many associated products—including laminates in solid colour laminates with facings such as metal foils, textiles, or wood veneers polyester laminates direct faced boards and composite boards comprising thin laminates bonded to substrates of various kinds. 

Particleboards are composed of discrete particles of wood bonded together by a synthetic resin adhesive, most commonly urea-formaldehyde or phenol-formaldehyde. The material is consolidated and the resin cured under heat and pressure. The strength of the product depends mainly upon the adhesive and not upon fiber... 

To determine the quantitative effects of this consolidation procedure, fabric disks cut from the extracted degraded fabric were used as substrates. These fabrics were torn on an Instron tensile testing machine as described earlier and patched with six applications of either the 0.1% dyed wood pulp or the 0.05% dyed Cellunier P slurry. The samples were then torn again on the Instron tester. The average breaking strengths and add-ons of the samples after six passes with slurry are reported in Table IV. A typical tom fabric and a patched fabric are shown in Figures 6 and 7. 

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