BUILDING MATERIALS PLASTIC

This article discusses traditional hull ding and construction products, ie, not made from synthetic polymers (see Building materials, plastic), including wood, asphalt, gypsum, glass products, Pordand cement, and bricks. The article presents information about each basic material, the products made from it, the basic processes by which the products or materials are produced, estimates of the quantity or doUar value of the quantities produced or used in the United States, and some pertinent chemical or physical properties related to the material. More detailed chemical and physical property data can be found in articles devoted to the individual materials (see Asphalt Cement Glass Wood). 

About 60% of the natural iron oxide pigments is used to color cement and other building materials (qv). About 30% is consumed in the production of paints. For coloring plastics and mbber, synthetic iron oxide pigments are preferred. The main advantage of the natural iron oxide pigments, as compared to the synthetic ones, is cost. However, the quaHty is inferior, and in most cases, they are consumed in close proximity to the mines. As colorants, the natural iron oxides are about 50% weaker than synthetically produced iron oxides. 

Nonionic surfactants and phenoUc resins based on alkylphenols are mature markets and only moderate growth in these derivatives is expected. Concerns over the biodegradabiUty and toxicity of these alkylphenol derivatives to aquatic species may limit their use in the future. The use of alkylphenols in the production of both polymer additives and monomers for engineering plastics is expected to show above average growth as plastics continue to replace traditional building materials. 

Phenolics are consumed at roughly half the volume of PVC, and all other plastics are consumed in low volume quantities, mosdy in single apphcation niches, unlike workhorse resins such as PVC, phenoHc, urea—melamine, and polyurethane. More expensive engineering resins have a very limited role in the building materials sector except where specific value-added properties for a premium are justified. Except for the potential role of recycled engineering plastics in certain appHcations, the competitive nature of this market and the emphasis placed on end use economics indicates that commodity plastics will continue to dominate in consumption. The apphcation content of each resin type is noted in Table 2. Comparative prices can be seen in Table 5. The most dynamic growth among important sector resins has been seen with phenoHc, acryUc, polyurethane, LLDPE/LDPE, PVC, and polystyrene. 

Extmded engineering thermoplastic stock can be treated like other building material ia that it can be machined, cut, and fastened. However, none of the engineering plastics can be considered a one-for-one substitute for metals or wood. For example, impact resistance must be considered, and glues, paints, etc, must be screened for chemical aggressiveness and adhesion capabiUty. 

The other principal thermal properties of plastics which are relevant to design are thermal conductivity and coefficient of thermal expansion. Compared with most materials, plastics offer very low values of thermal conductivity, particularly if they are foamed. Fig. 1.10 shows comparisons between the thermal conductivity of a selection of metals, plastics and building materials. In contrast to their low conductivity, plastics have high coefficients of expansion when compared with metals. This is illustrated in Fig. 1.11 and Table 1.8 gives fuller information on the thermal properties of pl tics and metals. 

Appreciating the role of chemistry in the world of work for example, that the range of building materials has been greatly expanded (e.g. plastics) since the advent of chemistry ... 

Substances that frequently cause symptoms in chemically sensitive people include pesticides, perfume, fresh paint, new carpets, many building materials, solvents, ink, smoke, vehicle exhaust, industrial fumes, plastics, petrochemicals, many cleaning products... 

Slenderness considerations are of particular importance to the ductility of structural steel members, Steel, as compared to other building materials used in blast design, is considerably thinner, both in terms of the overall structure anc the components of a typical member cross section. As a result, the effect of ovcratl and local instability upon the ultimate capacity is an important consideration. Width-thickness provisions must be applied not only to the extent that a full plastic capacity can be achieved, but to the extent that higher ductility ratios can also be safely reached. The width-thickness ratios, from Table 8-1 of Seismic Provisions for Structural Steel Buildings (AISC 1992) are used for this purpose. 

Wood-plastic composites (WPC) are used as building material for decking, fencing, siding. .. for the low maintenance constraints. US demand is forecast at 2.5 billion through 2008. 

The PBDEs (decaBDE, octaBDE, and pentaBDE) and are used as flame retardants in plastics, electronic equipment, printed circuit boards, vehicles, furniture, textiles, carpets, and building materials. Global demand has increased rapidly since the 1970s with 70,000 tonnes produced in 2001. Their flame retardant activity relies on decomposition at high temperatures, leading to the release of bromine atoms. This slows the chemical reactions that drive 02-dependent fires. HBCDs are a flame retardant added to extruded and expanded polystyrene that is used as thermal insulation in buildings. 

BFRs are used in a wide range of consumer products electronic components, textiles, foam in upholstery, carpets and building materials - all uses where the risk of fire necessitates caution. The increase in the use of plastics and flammable synthetic materials has contributed to the rise in the use of flame retardants. 

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