Plastics Plastics in Construction Ikmalzatul Abdullah

Plastics in Construction Alongside the packagings industry, the building industry is one of the most important customers for products made from synthetic, accounting for about 20% of the output the plastics industry. A selection of the synthetic materials used in building is arranged in the order thermoplastics, thermosets, elastomers and composite systems.

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Polyvinyl chloride (PVC) The outstanding properties of PVC such as chemical resistance, mechanical strength, multiple machining options and adjustability with regard to flexibility and impact toughness make it suitable for use in many areas, e.g. waste water pipes, window frames, rooflights, corrugated sheets, facade elements, waterproofing and floor coverings.

Cont.. Unplasticised PVC (PVC-u) is hard and brittle. The addition of plasticisers modify the material to form plasticised PVC (PVC-P). PVC can be manufactured in clear transparent, coloured transparent or opaque forms. It does not ignite easily and burns only with difficulty owing to its high chlorine content.

Polymethyl Methacrylate (PMMA) Better known by its trade names, e.g. Perspex, this material has very good optical qualities and a high scratch resistance. In many instances it can be used as a substitute for glass. Its high coefficient of thermal expansion must be taken into account, and unrestrained changes of length must be possible in the installed condition. The following products are made from PMMA: clear transparent and coloured sheets, double-walled panels, rooflights and splinter-proof panes.

Fibre Composites Embedding fibres in synthetic materials improves their mechanical properties. Fibre composite systems consist of a base (matrix) of curing resins or thermoplastics plus a fibre material which is responsible for high strength, rigidity and thermal stability. The designations for fibre-reinforced plastics (FRP) are given in the order fibre-matrix, e.g. glass fibre- reinforced polyester resin (GF-UP).

Cont.. The thermosetting materials suitable for use as a matrix are unsaturated polyester resins (UP), epoxy resins (EP) and cross-linked polyurethanes (PUR) in the form of casting resins. Among the thermoplastics, polypropylene (PP) is just one of those that can be used for fibre composites.

Cont.. The building components with loadbearing functions (e.g. structural sections, rooflights, shells) make use of reinforcement made from glass fibres (SF), carbon fibres (CF) and aramid fibres (AF). The latter two exhibit very high tensile strengths but are seldom used owing to their high price. The quantity of non-woven fabrics, meshes, textiles and rovings incorporated lies between 20 and 75% by mass.

Cont.. The combinations and the proportions of the individual components, the direction of the fibres, the elongation of the matrix at failure and the adhesion between fibres and matrix determine the properties of the composite material.

Applications for synthetic materials The manufacturers of plastic products exploit — not unlike a modular system — the specific properties of a synthetic material, the forming methods and the machining options in order to produce a tailor-made material for a corresponding range of applications. The same product is often available made from different synthetic materials. Users can then choose the best value for their money.

Applications • Loadbearing components: shells, sections Internal fitting-out, furniture: floor coverings, wall finishes, partitions • Building envelope: facade elements, rooflights, ribbon windows, roof waterproofing, membranes

Cont.. • Building services: drinking water and waste water pipes • Adhesives • Binders for organic and inorganic substances, coatings Thermal and sound insulation • Building preservation • Solar collectors

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