Plastics and the environment

A material which gets decomposed through natural processes, such as action by bacteria, is called biodegradable. Since plastic takes several years to decompose, it is not environment friendly. It causes environmental pollution. Besides, the burning process in the synthetic material is quite slow and it does not get completely burnt easily. In the process it releases lots of poisonous fumes into the atmosphere causing air pollution.

The materials that do not decompose through natural processes such as action of bacteria and takevery long time to degrade are called non- biodegradable materials.

All kinds of plastics, artificial fibers, tin, aluminium or other metal cans are non-biodegradable,

The materials which get decomposed through natural processes such as action of bacteria are calledbiodegradable materials. e.g. Parts of vegetables, fruits, leftover foodstuff, paper, cotton woollen clothes and wood etc. are biodegradable.  The table below shows the type of waste and approximate time in which it gets degraded.

DAMAGE CAUSED BY PLASTIC WASTE:

• The plastic bags and other items in the garbage are non-biodegradable. When garbage is converted into natural manure, it does not degrade. When this manure is spread in fields, the plastic does not allow the water to seep the soil, which has an adverse effect on the plants as well as recharging of groundwater.
• Stray cows and other animals sometimes eat plastic carry bags from the garbage dumps. The plastic carry bags choke the digestive tract of animals, thereby causing death.
•  Plastic carry bags and other articles clog the city drainage system as well as small freshwater drains, thereby causing a lot of inconveniences.
• Plastic, if burnt, produces very harmful gases which pollute the air.

MEASURES TO REDUCE THE USE OF PLASTIC MATERIALS:

• Reduce: Avoid the use of disposable plastic bags, instead make use of cotton or jute  bags for shopping.
• Reuse: Plastic items should be reused wherever possible.
• Recycle: It is better to recycle plastic waste. Most thermoplastics can be recycled.

RECYCLING OF PLASTICS:

Recycling of plastic involves collecting, sorting and processing plastic waste with an aim to reuse the material in manufacturing other products.

e.g. Polyester soft drink bottles could be melted down and the resulting molten material could be spun into fibers.

Two types of bins are made available by the municipality - a green bin and a blue bin to aid recycling of plastic garbage. Biodegradable wastes such as food items should be thrown into the green bin. Recyclable wastes such as plastic and glass, which cannot be degraded by microorganisms should be thrown into the blue bin.

Scientists all over the world are trying to produce biodegradable (decomposed by micro- organisms) and photodegradable (decomposes in the presence of sunlight) plastics.

To identify what type of plastic a particular product belongs to, numbers have been allotted to the different types of plastics. The principle followed is, the smaller the number, the easier it is to recycle.

Recycling Codes

IMPORTANT TERMS

• Acrylic or Acrylon or Orion: A synthetic fiber obtained by the polymerising acrylonitrite molecules obtained from petroleum products.
• Koroseal : Trade name of high polymer of vinyl chloride.
• Monomer: The simplest chemical molecule in a chain of polymer.
• Nylon: A superior synthetic fiber made by the polymerisation of amide molecules obtained from petroleum products.
• Plastic: A material which can be easily moulded into various forms.
• Plasticity: The property of a material due to which it can be moulded into various forms.
• Polyester (Polyethene Tetraphthalate): A plastic material prepared by the polymerisation of ethene-tetraphthalate.
• Polyester or Terylene or Terene or Dacron: A synthetic fiber obtained by polymerising rnolecules of pthalic acid and ethene glycol.
• Polymer: The product formed by the combination of a large number of monomers in a straight or crossed chain.
• Polymerisation: The process of combining monomers to form polymers under suitable physical and chemical conditions.
• Polypropene: The plastic material prepared by using the polymerisation of propene.
• Polythene: A plastic material prepared by the polymerisation of ethene gas.
• Polystyrene: A light polymer of polythene.
• Polyvinyl chloride (PVC): A plastic material prepared by the polymerisation of vinyl chloride.
• Rayon or Artifical silk: A regenerated cotton fiber by using chemical methods, which is smooth as silk.
• Teflon (Polytetra Fluoroethene): A plastic material prepared by the polymerisation of tetra-fluoroethene.
• Thermoplastics: Synthetic plastic materials obtained by gentle heating and moulding, such that the moulded materials can be reshaped by gentle heating.
• Thermosetting plastics: Synthetic plastic materials obtained by gentle heating and moulding, such that the moulded materials cannot be reshaped by gentle heating.
• The plastics have high chemical resistance. They are water resistant, light weight, very tensile, good insulators of heat and electricity. Furthermore, they can be made in any colour, shape and size.
• Polythene, polyvinyl chloride, polystyrene, nylon and terylene are the examples of thermoplastics.
• Bakelite, urea formaldehyde, polyurethene and malamine are the examples of thermosetting plastics.
• Polythene is used for making films for carry bags, adhesive tapes, etc. It is also used in making kitchen and laboratory ware, insulation of electric wires and as an anticorrosion coating on the articles made from iron.
• Polypropene is used for making ropes, containers, synthetic carpets, collapsible toys, shell of automobile batteries and as a packaging material.
• Polyvinyl chloride is used for making handbags,  raincoats, decorative vinyl flooring, soles of shoes, gramophone records, water pipes, water tanks, sanitary fittings and as an insulation for electric wires.
• Polyester is used for making crease resistant clothes, food packaging containers and magnetic tapes used in audio and video cassette recorders.
• Teflon has anti-stick properties and is used as a coating on the surface of baking or frying vessels and as a lubricant in those parts of machinery where oil cannot be applied.
• Polystyrene is used in insulating refrigerators, cold stores and in packaging expensive items, such as cell phones, television sets, etc.
• Rayon fiber is used in making bed sheets. On blending with wool, it is used for making carpets. Long filaments of it are used in making reinforced automobile tyres.
• Nylon fiber is used for making clothing, parachutes, stockings, fishing ropes and nets, tooth brushes, combs, zip-fasteners, hooks, washers, pulleys and for making reinforced automobile tyres.
• Polyester is used for making fabrics, sails of sailing boats, fire-hoses and conveyor belts.
• Acrylic fibers are used for making light weight blankets, shawls and yarn for hand knit sweaters.
• Artificial fibers have lustre, they do not shrink, need very little ironing, last longer, easy to clean.