Glass Fibres

Glass fibre is also known as fiberglass and is usually used as a reinforcing agent for many polymer products. The composites that form using the glass fibre and the polymer is called fibre-reinforced polymer (FRP) or glass-reinforced polymer (GRP).

The glass fibres are made of silicon oxide with addition of small amount of other oxides. There are two types of glass fibres. They are

1.    E-glass: this is the most used glass fibre. They have good electrical properties and so are called E-glass. Their tensile strength is 2400 MPa.

2.    S-glass: this type of glass fibre is very strong, stiff and temperature resistant and so is called S-glass. Their tensile strength is 4500 MPa.

Glass fibre is basically a polymer and is produced by spinning process, in which the molten glass out through a nozzle and the glass fibre is formed.

Glass fibres have very high strength. It is insensitive to moisture and is a good electrical insulator. It has low density and low modulus. Glass fibre has good resistance to chemicals, non-flammable and has low fatigue resistance. The cost of glass fibre is low and it makes it suitable to be used in a lot of areas.

The properties of glass fibre makes it suitable to be used in making sports car, boats, lorries, gliders etc. It is used in the field of architecture when making pods, domes etc., where light weight is necessary. Glass fibre is suitable to be used as electrical insulating tape, thermal insulators and waterproofing material.

Carbon Fibres

Carbon fibres are one of the toughest fibres used in textile industries. They are mostly used technical fibres after glass fibre and are the most expensive fibres used in textile industries and elsewhere. Carbon fibre is made from pure carbon in the form of graphite. Broadly it is divided into two types; PAN-based carbon fibre and Pitch-based carbon fibres.

PAN-based carbon fibres are those carbon fibres (chain of carbon atoms), which are obtained from polyacrylnitrile (PAN) by the process of heating and oxidation.

Pitch-based carbon fibres are fibres obtained by passing hot fluid pitch through a nozzle and pulling out the graphite threads.

PAN based carbon fibres have about 80% more strength than Pitch-based carbon fibres. PAN based carbon fibres can withstand temperatures upto 3500 ^oC. The pitch based carbon fibres can withstand temperatures of about 1300- 1400 ^oC.

For using carbon fibre, we first have to make a mould. On the mould a layer of carbon fibre is sprayed and on top of it adhesive is applied. This is then allowed to dry for some time. When the drying process is complete, the layer of carbon fibre is taken out of the mould and thus we obtain our required structure made up of carbon fibres.

Carbon fibres have very high strength, are lightweight and have high specific toughness and so it is used in making sports goods, aerospace, marine and road transport. Its high dimensional stability, high abrasion resistance and low coefficient of thermal expansion make it suitable to be used in making missiles, aircraft breaks, aerospace antenna and support structures. Also carbon fibres have good vibration strength, damping and toughness and so it is often used in making audio equipment and robot arms.

The carbon fibres are biologically and chemically inert. This property makes it suitable for making radiological equipment, chemical industry equipment, using in nuclear field, medical field (implants, artificial ligaments, tendons, etc.) etc.

Electrical conductivity and electromagnetic property of carbon fibres make it idle to be used as EMI and RF shields, automobile hoods, base of electrical equipment brushes, novel tooling etc.

Carbon fibres have a very unique property. They are self lubricating. This property along with fatigue resistance and high damping makes is very suitable for making textile machineries.