A number of different man made materials are now used for construction purposes. Of them, one of the most popular ones is glass reinforced plastic or GRP. It is commonly known as fibreglass.
GRP is a composite fibre consisting of plastic resin and glass fibres. A matrix is made of the thick treacly resin. It is then reinforced with glass fibre. The result is known as glass reinforced plastic.
Structure
The structural details of GRP are as follows:
? Two components are used in production of GRP. These are the polyester resin and the glass fibre for reinforcement.
? Unsaturated polyester dissolved in styrene is the most common material used. The polyester is produced by reaction between alcohol and organic acids. Different reactants are used to produce different types of resin.
? The dissolved polyester is set to harden - a process called curing. Organic peroxides are added as catalysts while cobalt naphanate acts as the accelerator.
? The curing takes place at room temperature using simple instruments. Hence it is suitable for low volume or even customized production.
? 'E' type glass fibres are used to reinforce this plastic. It contains calcium-alumina borosilicate with less than one per cent alkali content.
? Ingredients like silica, limestone, sand and kaolin are melted in a furnace. They are then extruded through bushings to form filaments which are then cured (coated) with protective chemicals. They are then gathered into loose bundles called roving's.
? Processes like Pultrusion, gun roving or filament winding are used to create the composite.
? The glass reinforced plastic matrix thus created is extremely strong. It has high tensile and compressive strength, high degree of resistance to chemicals, low electrical conductivity, low thermal conductivity and low coefficient of linear expansion. All these properties have made glass reinforced plastic a highly popular material for use in various walks of life. Add in the ease of the process of manufacturing and no wonder that it has become the material of choice in so many arenas.
Uses
Light weight, extreme strength, capacity to resist the vagaries of weather, various colours and textures are some of the leading reasons why glass reinforced plastic has found so many applications. Some of its common uses are as follows:
? Storage tanks are made from this material because it is strong and hard and resistant to corrosion. The tanks are used to store water or chemicals. It is also used to manufacture septic tanks
? They are used in construction industry for roofing, canopies, chimneys, sills etc.
? Piping in gas, waste water, drinking water, heating system use GRP.
? Sports equipments like surfboards, bicycles, kayaks, karts etc are manufactured.
? Finally, ladders, walkways, moulded gratings and other fabrications are used in factories.
