Properties and Uses of Plastics as a Construction Material
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Properties of Plastics as a Construction Material
Each plastic material has its own peculiar properties to suit its particular uses. The success of plastic as an engineering material will depends up on the selection of variety of plastic. Following are the general properties of plastic.
1. Appearance of Plastics
In the market there are so many types of models of plastics are available such as transparent, colored etc. suitable pigments are added in the process of manufacturing of plastic material to get these different properties. So, these will give good appearance to the structure and makes it attractive.
2. Chemical Resistance of Plastics
Plastics offer great resistance against chemicals and solvents. Chemical composition of plastics during manufacturing will decide the degree of chemical resistance. Most of the plastics available in the market offer great corrosion resistance. So, corrosive metals are replaced by plastic in the case of water carrying pipes, etc.
3. Dimensional Stability
Thermo-plastic types of plastics can be easily reshaped and reused. But in the case of thermo-setting type plastics, it is not possible to reshape or remold the material.
4. Ductility of Plastics
Ductile nature of plastic is very low. When tensile stress are acting on plastic member they may fail without any prior indication.
5. Durability of Plastics
Plastics with sufficient surface hardness are having good durability. Sometimes, plastics may affected by termites and rodents especially in the case of thermo-plastic types, however it is not a serious problem because of no nutrition values in plastic.
6. Electric Insulation
Plastics are good electric insulators. So they are used as linings for electric cables and for electronics tools.
Any type of finishing treatment van be given to the plastics. Mass production of plastic particles with uniformity of surface finish is done by having technical control during manufacturing.
8. Fire Resistance
The resistance to temperature or fire for varieties of plastics considerably varies depending upon the structure. Plastics made of cellulose acetate are burnt slowly. PVC made plastics do not catch fire easily. Plastics made of phenol formaldehyde and urea formaldehyde are fire proof materials.
Fixing of plastic materials is so easy. We can bolt, drill or glued to fix plastic material position.
The plastics made up of cellulosic materials are affected by the presence of moisture. The plastics made of poly vinyl chloride (PVC pipes) offers great resistance against moisture.
Maintaining of plastics are so simple. Because they do not need any surface finishing coats or paints etc.
12. Melting Point
Generally plastics have very low melting point. Some plastics may melt at just 50oC. So, they cannot be used in the positions of high temperature. Thermo setting type of plastics are having high melting point than thermo plastic type plastics. However, thermo setting types are cannot used for recycling. To improve the heat resistance of the plastics, glass fiber reinforcement is provided in its structure.
13. Optical Property
There are so many types of plastics. Some plastics are transparent which allows light in its original direction and some are translucent nothing but semi-transparent which allows light but changes light rays direction.
14. Recycling of Plastics
Disposal of plastics in the environment causes severe pollution. But it is not a serious problem because of its recycling property. We can use plastic waste disposal conveniently to produce drainage pipes, fencing, hand rails, carpets, benches etc.
15. Sound Absorption
By the saturation of phenolic resins we can produce acoustic boards. These acoustic boards are sound absorbents and provide sound insulation. Generally for theatres, seminar halls this type of acoustic ceilings are used.
Practically we can say that plastic is strong material but ideal section of plastic which is useful for structural component is not designed yet. Generally by reinforcing fibrous material into plastic improves its strength. If the strength to weight ratio of plastic is same as metals, then also we cannot give preference to plastics because of various reasons like, heavy cost, creep failure may occur, poor stiffness and sensitive against temperature.
17. Thermal Property
The thermal conductivity of plastics is very low and is similar to wood. So, foamed and expanded plastics are used as thermal insulators.
18. Weather Resistance
Most of the plastics except some limited varieties are capable of resistance against weathering. But, major problem is plastics when the plastics are exposed to sunlight, they are seriously affected by ultra violet rays and gets brittle. To prevent this, plastics are incorporated by fillers and pigments which helps to absorb or reflect the UV rays to surface.
19. Weight of Plastics
The Plastics have low specific gravity generally ranges from 1.3 to 1.4. So they are light in weight and easily transportable to any place in a large quantity.
Uses of Plastics in Building Construction
Plastics are manufactured in different forms such as moulding pipes, sheets and films. They are formed or expanded to produce materials of low density. Dissolved in solvents or dispersed as emulsions, they are used in paints, varnishes and adhesives.
At present, plastics find use in buildings mainly in thin coverings, panels, sheets, foams, pipes etc. skilful use of plastics will expand the usefulness and life of conventional building materials and help them to function more efficiently and economically.
A wide range of applications of plastics in buildings are given below:
1. Uses of plastics in façade panels, exterior covering, carpentry etc.
Sandwich panels covering with PVC (polyvinyl Chloride), plasticized plates and polyurethane foams.
Sandwich panels - asbestos cement covering and polyurethane foam core
Sandwich panel – polystyrene foam core and various coverings
Sandwich panel – covering with polyester laminated sheet and polyurethane foam core
Sandwich panel – enameled iron covering and polyurethane foam core.
Sandwich panel – covering with polyester laminated sheet glued to asbestos cement and polyesterene foam core.
Polyester coated concrete by moulding from an existing plates.
Sprayed polyurethane with sand and gravel agglomeration.
Epoxy resins and polyesters on various supporting media
PVC plasticized plates (spraying, coating or adhesive films)
Polyester epidermis available as permanent shuttering
PVC casing on metal moulding
Polyester laminated sheet on wooden moulding
PVC – chlorinated polyethylene compound
Polyester glass fibre and phenolic foam core
Plasticized PVC extruded sections
Rigid PVC extruded sections
Polyamide winding gear
Blinds and sunscreens
2. Uses of Plastics in Interior Covering, Floors, Walls, Ceilings, Doors, Partitions Etc
a) Wall Lining
Adhering films – vinyl coated fabrics or paper vinyl sheet doubling on fabric or paper etc.
Sprayed lining polyurethane
Laminate - Melamine and phenolic plastics – polyester
Wall tiles – polystyrene, PVC – tiles or mosaic
Coating – polyvinyl acetate
b) Floor Covering
Asbestos plastic slabs (asphalt tile type)
Vinyl asbestos slabs
Homogeneous semi-flexible vinyl slabs
Flexible, homogeneous or multi-layered vinyl slabs.
Homogeneous vinyl carpets (a) stuck, (b) laid
Vinyl carpets on felt (applied or coating)
Multi-layered coating with cellular structure on fabrics