Plastic Wood Producers

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

There are also reports of the production of boards and moldings from plasticized wood particles, pulp or sawdust without adhesives (5,8,59,60). By compressing and heating to high temperatures, particle boards can be produced which have mechanical properties comparable to conventional resin bonded boards. However, their specific gravity is on the average about twice that of ordinary commercial products (59). 

The core of a taxidermy specimen may contain wire, soft wood, and stuffing material, with the skin stretched over it and sewn together. The stuffing can be just about anything. Straw and excelsior were common, but other plant materials or hair have also been used. Taxidermists who need to make mounts of similar animals repeatedly often create body casts in plaster from a mold that can be reused. Modem taxidermists often use pre-cast body molds made of plastic, wood, fiberglass, or compressed paper. The nose, eyes, and other elements of the outer body that were, in life, composed of soft tissue are usually replaced by replicas made of glass, wax, plastic, or resin. Paint and resin or lacquer may have been applied to various areas of the body in an effort to produce a natural color, or to protect the skin. Taxidermy mounts may contain screws, tacks, or bits of wire inside, as part of the frame, and at the surface where they are used to hold various body parts in place, like hooves, andeis, or hom sheaths. 

For the present calculations we will adopt a value of 40 kg/m for the fire load density in urban areas. This may not be too far off from a reasonable value if city centers would be preferentially targeted and blast limited most of the fires in the central parts. However, it could be an underestimate, if this is not the case. We will also assume that only half of the buildings or half of the available fire load of 40 kg/m would actually bum, i.e. 20 kg/m (OTA, 1979). Altogether, in the urban area of 0.5 million km at least 10 gram of fuel would be consumed by fires. Most of this material will be wood in constructions and furniture, but it will also contain an appreciable fraction of synthetic organic polymers (plastics), which produce aerosol and soot much more efficiently than wood. 

Most of the major metal, glass, wood, and paper industries have made moves to join with plastics in producing combinations. 

Different forms/profiles of plastic/wood are used. Extruded profiles can contain at least 70 wt%, some up to 90%, wood content and produce wood-like appearance. Proper drying of the wood is required since it is hygroscopic otherwise burning can occur and properties are reduced. These products compete in different markets particularly the building and construction market and where water is located like a boating dock. It is entering the 8 billion USA residential siding market that is now at least half vinyl. 

Uses Urethane for textiles, artificial leather, furniture, flooring, industrial primers and coatings, and masonry sealants Features Exc. adhesion to plastics, metal, and wood produces coatings with exc. resist, to abrasion, UV and hydrolytic stability low VOC Properties Translucent disp. colloidal particle size dens. 8.98 Ib/gal vise. 200 cps flash pt. (PMCC) > 100 C pH 7-9 surf. tens. 49 dynes/ cm VOC 151.41 g/l Film props. tens. str. 6500 psi tens, elong. 450% (ultimate) anionic 40% solids Witcobond W-240 [Uniroyal]... 

These files are designed to remove material faster and with less effort, since the deep curved teeth produce small spiral filings which clear themselves from the tooth and so prevent clogging. Their principal use is in filing soft materials such as aluminium, lead, white metal, copper, bronze and brass. They can also be used on large areas of steel, as well as on non-metallic materials such as plastics, wood, fibre and slate. 

The most common types of the new WPC are produced by mixing wood flour and plastics to produce a material that can be processed just like a plastic but has the best features of wood and plastics. The wood can be from sawdust and scrap wood products. This means that no additional wood resources are depleted in WPC, waste products that currently cost money for disposal are now a valuable resource - recycling can be both profitable and ethical. The plastic can be from recycled plastic bags and recycled battery case materials although in demanding applications, new plastics materials are used. Thus it is interesting to use materials recovered from short life cycle applications in long life cycle applications. The benefits of WPC combine the best features of wood and plastics. 

Fabiyi, J.S., McDonald, A.G., Stark, N.M. Surface characterization of weathered wood-plastic composites produced from modified wood flour. In Proceedings of the 9th International Conference on Wood and Biofiber Plastic Composites, Forest Products Society, Madison, p. 271 WI (2007)... 

Park, C.B., Rizvi, G.M. and Zhang, H., 2002. Plastic Wood Fiber Foam Structure and Method of Producing Same, Canadian Patent, Application No. CA2384968, filed on May 3, 2002. 

With only 90 elements, one might assume that there could be only about 90 different substances possible, but everyday experience shows that there are millions of different substances, such as water, brick, wood, plastics, etc. Indeed, elements can combine with each other, and the complexity of these possible combinations gives rise to the myriad substances found naturally or produced artificially. These combinations of elemental atoms are called compounds. Since atoms of an element can combine with themselves or with those of other elements to form molecules, there is a wide diversity of possible combinations to make all of the known substances, naturally or synthetically. Therefore, atoms are the simplest chemical building blocks. However, to understand atoms, it is necessary to examine the structure of a typical atom or, in other words, to examine the building blocks of the atoms themselves. The building blocks of atoms are called electrons, protons, and neutrons (Figure 46.1). 

Phenol—formaldehyde (PF) was the first of the synthetic adhesives developed. By combining phenol with formaldehyde, which has exceptional cross-linking abiHties with many chemicals and materials, and a small amount of sodium hydroxide, a resin was obtained. The first resins soHdified as they cooled, and it was discovered that if it was ground to a powder with a small amount of additional formaldehyde and the appHcation of more heat, the mixture would Hquify and then convert to a permanently hard material. Upon combination of the powdered resin mixture with a filler material such as wood flour, the result then being placed in a mold and pressed under heat and pressure, a hard, durable, black plastic material was found to result. For many years these resulting products were called BakeHte, the trade name of the inventor. BakeHte products are still produced today, but this use accounts for only a small portion of the PF resins used. 

Economic Aspects. In 1994 there were 8 operational insulation board producers in the United States. These mills produced about 1.15 X 10 m (2). The number of mills and total production volume have also decreased in this industry, primarily as a result of changes in building codes and avadabihty of other competitive sheathing products. Both wood composite panels and plastic foam sheathings have captured a segment of these markets. 

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