Plastics In Building

Distillates from crude oil and natural gas, mainly naphtha, have become almost the only raw materials used in the plastics industry these days (Table 9.6). Prior to this, distillates from coal and even natural materials such as maize, cellulose, animal and vegetable proteins were used. Some of these are now being reintroduced.

Plastics are substances of natural or synthetic molecular organic material that can be composed to have a very wide variety of properties, including being easy to liquefy and mould. The basic 'building blocks' are called monomers, completed plastics are termed polymers; the reaction is known as polymerization. During production, substances such as chlorine, hydrochloric acid, fluorine, nitrogen, oxygen and sulphur are used as well as oil-based chemicals. Almost all plastics have a rich variety of additives including plasticizers, pigments, stabilizers against solar radiation, softeners, preservatives and perfumes (Table 9.8).

Plastics are divided into two categories: thermoplastics and thermosetting plastics (Table 9.7). Thermoplastics leave the factory complete, but can be worked to a certain extent with pressure and warmth, and can be cut. Common thermoplastics in the building industry are polyvinyl chloride, polystyrene, polypropylene, polyethylene and thermoplastic polyesters. Polyethylene and polypropylene are often labelled as polyolefins. Important thermoplastic polyesters are polyethylene terephthalate and polycarbonate. Thermosetting plastics differ from thermoplastics in that they are not finished products; the product is completed by secondary companies or at the building site where hardeners are added. In this group we find the two-component plastics, as epoxy and polyurethane, and synthetic adhesives like phenol-formaldehyde and urea-formaldehyde. Synthetic rubbers are a subgroup of thermosetting plastics with

Table 9.6 Important building related oil based chemicals with environmental risk

Oil based chemical*

Area of use

Acrolein

Polyester, polyurethane, acrylates, etc.

Acrylic acid

Acrylic plastics and paints

Acrylonitril

Styren butadiene rubber(SBR), acrylic fibres

Amines

Silicone, polyurethane, epoxy, organic pigments in paints

Benzene

Polystyrene

Bisphenol A

Polycarbonate, epoxy, polyvinyl chloride

Butadiene

Acrylonitrile butadiene styrene (ABS), Styrene butadiene rubber (SBR), polystyrene

Cadmium

Stabilizer in polyvinyl chloride

Carbendazim

Silicone

Chlorofluorocarbons (CFC)

Polystyrene foam, polyurethane foam

Chloromethane

Silicone, butyl rubber (IIR), polystyrene foam

Chloroparaffins (CP)

Softeners and flame retarders in polyvinyl chloride, polyurethane, sealants and paint

Chloroprene

Chloroprene rubber and adhesives

Decabromodiphenyl ether

Flame retarder in polyamides and polyolefins

Dichloroethane

Polyvinyl chloride

Dichloromethane

Polyurethane foam

Dimethylethanolamine

Polyuretane, epoxy

Epichlorohydrin

Epoxy

Ethyl benzene

Polystyrene

Ethylene

Polyethylene

Formaldehyde

Phenol formaldehyde foam, glue in chipboard, plywood, etc.

Hexabromocyclododecane

Polystyrene foam

Hydrochlorofluorocarbons (HCFCs)

Polystyrene foam, polyurethane foam

Hydrofluorocarbons (HFCs)

Polystyrene foam, polyurethane foam

Isocyanates (TDI, MDI, etc.)

Polyurethane, glue, varnish

Methyl metacrylate

Polymethyl metacrylate

Nonylphenol

Pigment paste, alkyd varnish, epoxy paint and varnish

Octabromodiphenyl ether

Flame retardant in acrylonitrile butadiene styrene (ABS) polystyrene, polyamides

Organophosphates (TCEP, TCPP, etc.)

Biocides, flame retardant in polyuretane and polyisocyanurate foams, polyvinyl chloride, adhesives

Phthalates (DEHP, DIBP, BBP, DINP, etc)

Softener in polyvinyl chloride, synthetic rubbers, polystyrene foam, synthetic carpets, paint, varnish, glue

Phenol

Phenol formaldehyde foam, glue in laminated timber, OSB-boards

Phosgene

Polyurethane, polycarbonate

Polybrominated diphenyl ethers (PBDE)

Flame retarders in polyethylene, polypropylene, acrylonitrile butadiene styrene (ABS) polystyrene, polyamides

â– Table 9.6 (Continued)

Oil based chemical*

Area of use

Siloxanes (Octamethylcyclotetrasiloxane, etc.)

Silicone

Styrene

Polystyrene, polyester, Styrene butadiene rubber (SBR), Acrylonitrile butadiene styrene (ABS)

Tetrabromobisphenol A (TBBPA)

Flame retardant in epoxy, polyurethane, acrylonitril butadiene styrene (ABS)

Tetrahydrofuran

Seam sealer in flooring of polyvinyl chloride

Vinyl chloride

Polyvinyl chloride

* See Table 2.5 for details on toxicity.

* See Table 2.5 for details on toxicity.

almost permanent elasticity. Plastics can be foamed, extruded, moulded, rolled out into thin foils, etc.

Polyvinyl chloride (PVC) was one of the early plastics. The polymerization process was discovered by accident by the French chemist Henri Regnault in 1838. PVC was first produced commercially 100 years later. In 1865 celluloid (a mixture of cellulose nitrate and camphor) was patented. Bakelite was the first really successful plastic. It comprised mainly synthetic phenol formaldehyde resins and was patented in 1909. Other milestones in plastics included the first production of polystyrene in Germany in 1930, polyethylene and acrylates in 1933, polyester in 1942 and silicones in 1944.

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