CONTENTS
Plastic is an organic material prepared out of resin. It may or may not contain fillers, plasticisers and solvents. Plastic may be defined as a natural or synthetic organic material which are having the property of being plastic at some stage of their manufacture when they can be moulded to required size and shape.
Shellac and bitumen are the natural resins used as plastic for a long time. In 1907, Blackland produced synthetic resin from the reaction of phenol and formaldehyde. The resin was hardened under pressure and heat to produce useful plastic articles.
PROPERTIES OF PLASTIC
[1] COLOUR
Some plastics are completely transparent. Using pigments plastics of any attractive colour can be produced.
[2] DIMENSIONAL STABILITY
It is dimensionally stable to a great extent.
[3] DURABILITY
Plastic offers great resistance to moisture and chemicals and hence more durable.
[4] ELECTRICAL INSULATION
The plastics possess excellent electrical insulating property.
[5] FIRE RESISTANCE
The phenol-formaldehyde and urea-formaldehyde plastics resist fire to a great extent and hence they are used as fire proofing materials.
[6] STRENGTH
The plastics are reasonably strong. Their strength may be increased by reinforcing with various fibrous materials. Attempts are being made to produce structurally sound plastics.
[7] SPECIFIC GRAVITY
The specific gravity of plastics is very low and hence convenient to handle.
[8] DUCTILITY
The plastics are not ductile and hence they fail without giving warning.
[9] FIXING
Plastics can be bolted, drilled, glued, clamped or simply push fitted in position.
[10] MAINTENANCE
There is no maintenance cost for plastic articles i.e., they do not need painting and polishing.
TYPES OF PLASTIC
Primarily there are two types of plastics
[1] THERMOSETTING PLASTIC
It needs momentary heated condition and great pressure during shaping. When heated cross linkage is established between the molecules and chemical reaction takes place. During this stage shape can be changed with pressure. This change is not reversible. The scrap of such plastic is not reusable. Bakelite is an example of such plastic.
[2] THERMOPLASTIC
In this variety, the linkage between the molecules is very loose. They can be softened by heating repeatedly. This property helps for reuse of waste plastic. These plastic need time to cool down and harden. These plastics are to be kept in moulds till cooling takes place completely. Bitumen, cellulose and shellac are the examples of this variety of plastics.
USES OF PLASTIC IN CONSTRUCTION
There are variety of plastics made to suit different uses. The typical uses of plastics in buildings is listed below:
[1] Plastic is used for Corrugated and plain sheets for roofing.
[2] Plastic is used for making jointless flooring.
[3] Its used as Floor tiles.
[4] Overhead water tanks.
[5] Bath and sink units.
[6] Cistern hall floats.
[7] Decorative laminates and mouldings.
[8] Window and door frames and shutters for bathroom doors.
[9] Lighting fixtures.
[10] Electrical conduits.
[11] Electrical insulators.
[12] Pipes to carry cold waters.
Love this post and you love to get a copy
Click on the button below to get the PDF file and Read Offline.