Karnataka Science and Technology Academy

Department of Science and Technology, Government of Karnataka

Life is Polymeric in Nature !!! – Prof. D. Channe Gowda

6 min read

The number of polymers used by mankind in daily life is countless. The daily life have not been easier and colourful without the discovery and varied applications of polymers. Use of polymers in the manufacture of plastic buckets, cup and saucers, children’s toys, packaging bags, synthetic clothing materials, automobile tyres, gears and seals, electrical insulating materials and machine part has completely revolutionized the daily life as well as the industrial scenario (Fig 1). In fact, the polymers are the backbone of four major industries viz. plastics, elastomers, fibers and paints & varnishes. Even living systems are made up of various complex molecules (polymers) like carbohydrates, proteins, nucleic acids, lipids, etc.

Polymers have not been discovered overnight. They came out of long and persevering studies by a host of motivated scientists whose work has enriched human life. Today, the overall insight into polymer science and technology is so deep that a material scientist can create an almost limitless range of new materials. A bullet proof material like polycarbonate which combines the transparency of glass and the strength of steel is one such example. In future, we can expect even more formidable utility combinations to emerge as the polymer chemist becomes an even better ‘architect of molecules’.

Polymers are compounds of very high molecular weight (103-107u) formed by the combination of a large number of simple molecules or monomers. All polymers are macromolecules.

Polymers are obtained through chemical reaction of monomers. Monomers have the ability to react with another molecule of same type or different type in a suitable condition to form the polymer chain. This process in nature has resulted in the formation of natural polymers while the synthetic polymers are man-made. Today, the polymer industry has rapidly developed and is larger than the copper, steel, aluminium and some other industries combined.

The orientation of monomers and obtaining high molecular weight polymers is very important in polymer chemistry. The proper oriented polymers are stronger than steel and very good conductor of electricity. Conducting power is even more than that of copper. Dyneema, the strongest commercially available fabric is an oriented polyethylene polymer. Its molecular weight is 100 times greater than that of high density polyethylene (HDPE). A rope made of Dyneema can lift almost 60000 kg while steel rope of similar size fails before the weight reaches 6500kg. The introduction of Zeigler-Natta catalyst [Et3Al:TiCl4 in 1:1 ratio] by Karl Ziegler and Giulio Natta has brought about a revolution in the field of polymerisation by producing highly oriented and high molecular weight polymers which led them to receive Nobel Prize.

Polymers are classified as natural, synthetic and semi-synthetic based on source; fibres, elastomers and plastics based on the kinds of intermolecular forces present in the molecules of polymers and homo and co-polymers based on the nature of monomers present in the polymers. The polymers may be natural or synthetic, inorganic or organic, they have numerous applications in our daily life.

Organic polymers play a crucial role in living things providing basic structural materials and participating in vital life processes. The solid parts of all plants are made up of polymers viz. cellulose, lignins and various resins. Wood resins are polymers of simple hydrocarbon, isoprene. Another familiar isoprene polymer is rubber. Other important natural polymers include proteins which are the polymers of amino acids; and nucleic acids which are polymers of nucleotides – complex molecules composed of nitrogen containing bases, sugar and phosphoric acid. Starch,  important source of food energy derived from plants are natural polymers composed of glucose. Glycogen, storage food of animals is also polymer of glucose. Graphite and diamond, both composed of carbon are inorganic natural polymers.

Synthetic polymers are produced in different types of reactions like addition and condensation. They may follow free radical, cationic and anionic or coordination mechanism. The man-made polymers (synthetic) synthesized are countless. It include polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE, TEFLON), polyacrylonitrile (PAN, orlon), phenol-formaldehyde resin (bakelite, Novolac), melamine-formaldehyde resin,  urea-formaldehyde resin,  polymethyl methacrylates (PMMA), polyesters (terylene or dacron or mylar), glyptal, nylons,  epoxy resins, polycarbonates, vulcanised rubber (ebonite), neoprene, Buna-N, Buna-S, butyl rubber, polyurethane rubber, etc.  The most important representation of inorganic synthetic polymer family are the silicones and glasses.

The polymers find applications in various types of fields and to mention a few:

  • Agricultural field:  mulching films, greenhouse films, etc.
  • Medical field: syringes, capsules, medicine packaging, etc.
  • Transport field: car bumpers, wheel covers, etc.
  • Electrical field: wire crating, switches, etc.
  • Household applications: bowls, kitchen accessory, etc.
  • Specialty Polymers: aeroplane, etc.

The greatness about polymers is that we want to use polymers to make stuff rather than wood, metal, glass or ceramics. Most polymers are lighter, harder to break, long lasting, recyclable, easier to form into shape, safe, non-toxic and cheaper. Also by choosing the right kind of polymer, our products can be soft or hard, flexible or stiff or anything we want. Most polymers will last a long, long time. That’s good – especially if it is used to make clothes, jars, even chairs, etc.  But it’s bad when polymers get thrown away. Some polymers are easier to recycle than others. It’s important to recycle the polymer products so that our landfills don’t get filled up so fast.

The largest application of synthetic polymers is as plastic. Portion of it is used as throwaway containers and packaging materials. Plastic do not degrade by themselves i.e., they are non-biodegradable. These polymers create pollution as there are grater chances of environmental damage. So most of the countries including India  are banning the use of plastic. Plastics are threat to animal life especially the marine world since their environment is full of plastic which adversely affect their natural habitats and also are responsible for the death of animals mainly because of suffocation. Since plastics are manufactured from petroleum which brings a host of issues like destruction of habitat, extraction of crude oil, security issues, chemical manipulation, etc., (Fig 2).

This is not supposed to happen because this development utilizes man power of intellectual as well as lot of funding. Further, this does not mean to say that plastic has no place in society but its proper use, disposal and maintenance will leave the society healthier. Hence, instead of banning the use of plastic, research should continue to find out the solution of their degradation. In this sense, a good planning is highly essential and also vital before the product development. One such example for the execution of product with lack of planning is the case of LHRH (luteinizing hormone releasing hormone).

In 1980’s, most of the laboratories across the globe were busy synthesizing LHRH analogues to control the fertility. Scientists succeeded in synthesizing the antagonists to inhibit the LH and FSH which are responsible for fertility. But they never thought about the side effects what if LH (luteinizing hormone) and FSH (follicle-stimulating hormone) were not released? As a result, when these hormones are inhibited,  side effects like oedema formation took place which led to lot of complications. Eventually, the analogues found way toward the sink as they did not serve the purpose. Therefore, a proper planning is highly essential before putting any idea in place as the learned people say that “proper planned work is half done”.

All in all it may be taken into consideration that some polymers (like plastic) as on today cannot be banned completely disregarding their multidimensional applications which is the need of the hour. May be it has become a part of human life today but in coming days people should be wise so also the authorities should take necessary steps and precautions.

To conclude, our lives have become beautiful, meaningful and colourful as the mother Nature has bestowed us with such magnanimous gift called “polymers” and we the humans should be responsible to tactfully handle them now and leave the rest to future also. 

Prof. D. Channe Gowda
Member, KSTA
Former Chairman, Department of Studies & Research in Chemistry,
University of Mysore, Manasagangotri, Mysuru-570 006

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