SYNTHETIC MATERIALS

SYNTHETIC MATERIALS

Polymer:- 

A polymer is made of small units.The monomers combine end-to-end under certain condition to form a polymer. For example cellulose is a polymer of glucose while hemoglobin is a polymer of amino acids.

Polymerization:-

                                    The process of formation of polymer from a monomer is called polymerization.

Polymers can be classified into three types

• ·         NATURAL,

• ·         SEMI- SYNTHETIC

• ·         SYNTHETIC 

TYPES OF FIBRES

Fibres are also Polymers, so they are of above three types.

TYPES OF FIBRE	EXAMPLES
Natural	Cotton, jute, Silk, wool
Semi synthetic	Rayon (viscous, cuprammonium and acetate )
Synthetic	Polyester, nylon and acrylic.

 Fabrics made up of polyester and nylon are heat set.

NATURAL FIBRES

                         Natural fibres are fibres which are made up by nature (from plant or animal) . Natural fibres are hydrophobic that is they absorb moisture. For example: wool, cotton or silk etc.

Synthetic fibres:

                         Synthetic fibres are the fibre which are made up by man in factory or in in laboratory. Synthetic fibres are hydrophobic that is  they repel moisture. For example nylon, acrylics, polyesters etc.The most common example of semi synthetic is Rayon.

Rayon

It is a semi synthetic fibre which is formed by cellulose and it is present in three different variety-

• ·         VISCOUS,
• ·         CUPRAMMONIUM OR CUPRO,
• ·         ACETATE RAYON.

Viscose rayon-

            It is formed by the mixture of cellulose and sodium hydroxide and carbon disulphide. After the mixture of these three it will form a viscous liquid. This viscous liquid is passed forcefully through spinnerets which have small holes. By this of filaments of viscose rayon are obtained.

Cuprammonium rayon or cupro

                        A copper sulphate solution is treated with Ammonium hydroxide solution then cuprammonium hydroxide is formed. Cellulose is dissolved in this solution. The resulting solution is pass through the spinnerets into an acid bath to give the filaments of the cuprammonium rayon.

Acetate rayon

                        In this case cellulose is dissolved in a mixture of Acetic Acid sulphuric acid and some other chemicals. The solution is forcefully passed through the spinnerets that to obtain the filament of Acetate rayon.

Polyesters 

                        It is a synthetic fibre. It has property e that it can be stressed up to several times original length. Terylene and Dacron belong to this class of the synthetic fibre.
Uses 

1.it is used to make cloth.

 2.it is used to make a bottle and insulating tapes.

Polyamide or nylon

                        Nylon 6 and nylon 6,6 belong to this category. Nylon 6 is made up of organic compound which contains carbon atoms. Nylon 6,6 is made up of more complicated monomer.
Uses

1. It is used to make rope.

2. It is used for women's wear .

Acrylic

It is a the substituent of natural wool. This Polymers decompose without melting so they are dissolved in a suitable solvent and the solution is force through the splendid to obtain the filaments.

·         It cannot be easily acted by moisture, chemical or bacteria.

Uses

            It is used to make upholstery and artificial furs.

Advantages of Synthetic fibre-

1.      For synthetic fibres we do not have to depend on the plants and the animals.

2.      Synthetic fibres like polyester and nylon can easily be heat-set.

3.      Synthetic fibres are much stronger and hence more durable than the natural fibre.

4.      Synthetic fibres are cheaper.

5.      Synthetic fibres are not easily acted by the moisture, chemical or bacteria.

Disadvantages of synthetic fibre

1.      Clothes made up of pure synthetic fibres are lustrous.

2.      Synthetic fibre made before burning. Clothes made up of synthetic fibre stick to the skin when in contact with the flame, causing burns.

3.      Synthetic fibres are hydrophobic that is they repel moisture.

4.      Electrical charge accumulate on synthetic fibre due to rubbing together as well as on to the skin. electrical charge irritate the skin.

What are the uses of synthetic fibre?

1.      It is used for making bed sheets, curtains, Towels, cushion covers, mosquito net and fishing nets.

2.      It is also used insulation for electric wires.

Plastic

·         Plastic surgery synthetic material that can be moulded into any permanent shape.

·         For example polythene carry bags plastic bottles soda water crates and the body of your TV, computer.

·         Plastic are cheap, light and strong.

·         They can be moulded into different shapes-this property is known as plasticity.

Plastics are of two types--

1.      Thermoplastics or thermoplast

2.      Thermosetting plastic or  thermosets

THERMOPLASTIC

Thermoplastics –

The plastic which can be moulded again and again by heating into any shape that kind of Plastics are known as thermoplastic. For example bottles, lens or chairs.

Thermoset or thermosetting plastic

The plastic which cannot be moulded again and again by heating into any shape that kind of plastics are known as thermoset  or thermosetting plastic.

For example, Electrical switches,chairs etc.

THERMOSETTING PLASTICS