Civil Engineering Reference
In-Depth Information
Table 9.6: The use of plastics in a typical dwelling
Use
kg
%
Flooring
800
30
Glue, mastics
700
26
Pipework
425
16
Paint, filler
275
10
Wallpaper, sheeting (e.g. vapour barrier)
200
8
Thermal insulation
100
4
Electrical installation
100
4
Cover strips, skirtings, etc.
50
2
Total
2650
100
moulds. The 'building blocks' are called monomers, the completed plastic is
called a polymer and the reaction is polymerization. During production process-
es 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, preservatives and perfumes.
Plastics are divided into two categories: thermoplastics and thermosetting plas-
tics (see Table 9.7). Thermoplastics leave the factory complete, but can be worked
to a certain extent with pressure and warmth, and can even be cut. Common ther-
moplastics in the building industry are polyvinyl chloride, polypropylene, poly-
ethylene and polystyrene. Thermosetting plastics differ from thermoplastics in
that they are not finished products - the product is completed by smaller compa-
nies or at the building site where hardeners are added using two component plas-
tics, amongst them polyester, epoxy and polyurethane. The synthetic rubbers are
a sub-group of thermosetting plastics with almost permanent elasticity. The basic
thermoplastics can be foamed up, extruded, moulded, rolled out to thin foil, etc.
Polyvinyl chloride was the first plastic. Polymerization was discovered by acci-
dent by the French chemist Henri Regnault in 1838. PVC was first produced com-
mercially 100 years later. In 1865 celluloid (a mixture of cellulose nitrate and cam-
phor) was patented. Bakelite plastic was the first really successful plastic. It com-
prised mainly synthetic phenol formaldehyde resins and was patented in 1909.
Other milestones in plastics include the first production of polystyrene in Germany
in 1930, polyethylene and acrylates in 1933, polyester in 1942 and silicones in 1944.
Pollution related to the most important building plastics
Depending on their type, plastics give off environmentally damaging substances
during production and use, and when they are deposited or dumped. Primary
 
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