Man Made Materials | SSC CGL Tier 2 - Study Material, Online Tests, Previous Year PDF Download

We use various types of materials in our daily life. Those materials are made up of various materials like wood, glass, plastic, thread, soil, metals, rubber, etc.

Natural material : Naturally obtained materials that we use for our daily needs are natural materials.
Example:  Wood, rock, minerals, water are natural materials.

Man-made materials : Materials manufactured in the factories after research on the natural materials are called man-made materials.
Example: Glass, plastic, artificial threads, thermocol, etc.

Plastic 

Plastic is a man-made material made up of organic polymers.

• Plastics are derived from natural materials such as natural gas, oil, coal, minerals and plants.
• The first synthetic plastics were derived from cellulose, a substance found in plants and trees. This cellulose was heated with chemicals and resulted in a plastic like material.
• Plastic is produced in factories by suitable chemical reactions.

Types of plastic

According to structure, plastic is of two types :

• Linear
• Circular

According to the effect of heat, plastic is of two types :

Thermoplastic : The plastic that can be moulded as per our wish.

• Thermoplastic substances can be recycled and reused.
• E.g. Polythene, PVC manufacturing the toys, combs, plates, bowls, etc.

(ii) Thermosetting : Plastic whose shape cannot be changed on heating.

• Thermosetting plastic cannot be reused again.
• E.g. The one that is used in Electric switches, coverings over the handles of cookers.

Properties of plastic

• Plastic is non-corrosive.
• It is non-degradable as it does not decompose.
• The factors such as humidity, heat, rain, etc. do not affect plastic.
• Any coloured item can be manufactured from plastic.
• Plastic shows property of plasticity. Thus it can be moulded into any shape that is needed. .
• Plastic is a bad conductor of heat and electricity.
• Plastic is light-weight and thus preferred for carrying.

Degradable materials: Those materials that can be naturally degraded, are called degradable materials.

• Degradable substances are not accumulated in the nature.
• Degradable substances emit foul odour when they are being decomposed.
• Usually microorganisms play a part in the degradation process, hence such substances are also called biodegradable. Example: Vegetables, fruits, wood, cotton or wool fibres, etc.

Non-degradable materials: The materials that do not degrade through natural processes are called non-degradable materials.
Example: Plastic being non-degradable, it is an environmental pollutant.

• The use of plastic should be reduced as far as possible as it causes environmental pollution. Jute bags, cloth bags, paper bags, etc. can be a better option for the plastic carry bags.
• However, certain plastic items are almost irreplaceable such as plastic in healthcare sector which is in the form of saline bottles or syringes.
• Microwave cookware is plastic. In microwave, metal cookware cannot be used. Teflon used for scratch-resistance, is a kind of plastic.
• Airplanes need some plastic parts.
• Lenses and artificial teeth are made up of polyacrylic.
• There are more than 2000 different types of plastics. But one must be careful in plastic use.

4R Principle : Use of 4R principle is important in reducing the environmental pollution. It also promotes sustainable living.

1. Reduce - Minimal use
2. Reuse - Using the resources again
3. Recycle - Using again after Processing
4. Recover - Obtaining the materials again.

Thermocol:

• Thermocol is modern man-made material made from polystyrene.
• It can be transformed into liquid state when heated at more than 100 °C temperature. On cooling, it returns to the solid state.
• Therefore, any desired shape can be given to it.
• It acts as a good shock-absorber and hence used as a packing material to transport brittle material.
• It is a bad insulator of heat and hence used for storing fish and other perishable articles in market.

Adverse effects of excessive use of thermocol on environment and human :

• Disease causing and carcinogenic effect: The presence of carcinogenic substances in thermocol, specifically styrene, raises concerns about its potential to cause cancer. Prolonged exposure to thermocol increases the risk of developing blood cancer or lymphoma in individuals.
• Non-biodegradable nature : Natural degradation of thermocol does not take place easily. If it is destroyed by burning, poisonous gases are released through it causing toxic air pollution.
• Excessive use : Thermocol is commonly employed in large gatherings, but the use of thermocol plates and cups can have adverse effects on health. Reheating food stored in thermocol poses a potential hazard, as styrene may dissolve into the food. Opting for meals served in thermocol cups or plates not only contributes to environmental issues but also poses health risks.
• Occupational hazard to those working in thermocol factory: Extended exposure to thermocol can lead to various health issues, affecting the eyes, respiratory system, skin, and digestive system. Additionally, prolonged contact with thermocol is particularly harmful to pregnant women, potentially inducing abortion. The presence of liquid styrene in thermocol can also result in skin burns.

Glass

Glass is a synthetic material widely utilized, and its discovery occurred unexpectedly when Phoenician traders were cooking in the desert. They realized that by heating sand and limestone together, they could form glass, leading to the eventual development of glass production techniques.

• Glass is hard but brittle solid and crystalline material formed from mixture of silica (SiO2) and silicate.
• Different types of glasses are dependent upon the proportion of silica and other components in the glass. Example: Sodalime glass, boro-silicate glass, silica glass, alkali-silicate glass, etc.

Production of Glass

• For glass production, mixture of sand, soda, lime, and small quantity of magnesium oxide is heated in furnace.
• Sand, i.e. silicon dioxide melts at 1700 °C. To melt the mixture at low temperature at 850 °C, pieces of discarded glass are added to it.
• After all the ingredients of mixture are liquified, it is heated up to 1500 °C and immediately cooled.
• Sudden cooling makes the mixture homogeneous, amorphous and transparent instead of crystalline.

Properties of Glass:

• On heating, glass becomes soft and can be moulded into any shape.
• Density of glass depends upon its ingredients.
• Glass is slow conductor of heat. On quick heating of cool glass or on quick cooling of hot glass, it cracks / breaks.
• Being bad conductor of electricity, glass is used as insulator in electric appliances.
• Being transparent, most of light passes through the glass.
• Oxides of either chromium, vanadium or iron in the glass, makes large amount of light to be absorbed in glass.

Types of Glass and Uses:

1-Silica glass : This is produced by using the silica. Items made up of silica glass show minimum expansion on heating.

• Features/Uses : It is not affected by acid and alkali. Due to this, silica glass is used to produce laboratory glass-wares.

2-Borosilicate glass : Borosilicate glass is produced by melting the mixture of sand, soda, boric acid and aluminium oxide.

• Features/Uses : This glass does not show any effect on medicines. Hence, the bottles made up of borosilicate glass are used in pharmaceutical industry to store the medicines.

3-Alkali silicate glass : Alkali silicate glass is produced by heating the mixture of sand and soda.

• Features/Uses : As this glass is soluble in water, it called as 'water glass'.

4-Lead glass : Lead glass is produced by melting the mixture of sand, soda, limestone and lead oxide.

• Features/Uses : It is very clear / transparent, it is used in manufacturing of light bulbs, tubes, etc.

5-Optical glass : Optical glass is produced from the mixture of sand, soda, limestone, barium oxide and boron.

• Features/Uses : This type of pure glass is useful in production of spectacles, lenses, microscopic lenses, etc.

6- Coloured glass : Soda lime glass is colorless.So as to impart a desired colour, oxide of specific metal is mixed during manufacturing process.

• Features/Uses :  Ferrous oxide is mixed to get bluish green glass and copper oxide to get red glass.

7-Processed glass : So as to improve the quality and utility, some processing is performed on glass.

• Features/Uses : Various types like reinforced glass, plain glass, fiber glass, fen glass, translucent glass, etc. are produced.

Effect of glass on environment :

• Greenhouse gases like sulphur dioxide, nitrogen dioxide, carbon dioxide are released due to burning of fuel at 1500 °C, at the time of glass production.
• Being non-degradable, the glass pieces remain unchanged in the ecosystem, causing harm to living organisms