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Vol. 13 No. 2 - April 2007
‘Golden Jubilee Number’

Plastics in the Environment

By: M. M. Sharma, F.R.S.* & R. A. Mashelkar, F.R.S**

Plastics have moulded the modern world and transformed the quality of life. There is no human activity where plastics do not play a key role, from clothing to shelter, from transportation to communication and from entertainment to health care. Plastics, because of its many attractive properties, such as lightweight, high strength and ease of processing, meet a large share of the material needs of man. From practically zero in the fifties, humankind today consumes greater than one hundred and fifty million tons of plastics. We truly live in a ‘Plastic Age’. Our daily lives would be very much poorer without these benign and environmentally friendly materials. Plastics possess a unique combination of properties. Plastics can be super tough, rigid as well as flexible, transparent as well as opaque and can allow selective permeation or act as a barrier material.

Nature has produced ‘plastic’ – like materials for centuries. Silk and cellulose are example of natural polymers. Reference to Shellac, a thermoplastic can be found even in Mahabharatha!

Growing population and consumption in India has put severe pressure on our natural resources and fragile ecosystems. The material needs of our population are growing and plastics offer a cost-effective alternative.

Plastics are employed in myriad applications where they actually conserve natural resources. For example, asceptic packaging of food in barrier packaging films will render refrigeration unnecessary, saving capital and energy. Edible oils and milk are packaged in flexible packages eliminating the use of tin and glass containers. Rigid HDPE barrels are used for bulk chemical storage instead of steel drums. Apart from conserving natural resources, use of plastics in these applications saves transportation fuel as plastics are substantially lighter than tin, glass or steel.

Safe drinking water packaged in PET bottles are a very common sight now-a-days. They provide confidence to consumer on the quality of water and help reduce waterborne diseases. Advanced polymeric membranes help purify water from viruses and bacteria. They also provide potable drinking water from sea and brackish water through a process of desalination.

The fact that plastics are made from hydrocarbons derived from petroleum, which is non-renewable, has raised questions concerning its sustainability. Nevertheless, the  consumption of petroleum hydrocarbon for the production of plastics is less than 5%, the

balance being consumed as fuels and energy source. Consequently, the concerns about sustainability of plastic materials is somewhat exaggerated. On the contrary, processing of many natural materials (glass, paper, wood, metals) consume far more energy and thus lead to greater consumption of fossil fuels. Additionally, research and development work currently in progress globally will provide future opportunities to make some of the plastics from biomass and other renewable resources. Thus, plastic manufacture will become even more sustainable in the years to come. It is fair to say that plastics replace several natural materials, which are either scarce, consume more energy for processing or cause damage to the eco-systems during their production. Thus use of plast5ics makes a positive contribution to the sustainability of earth’s resources.

Another issue that is often discussed is whether because of their non-biodegradability, plastics will cause damage to our ecosystems. The signature of all natural materials made by biological processes is that they are biodegradable and bio-assimilable. The long life and desirability of plastics, which have made them a material of choice for many applications is seemingly a disadvantage when it comes to their disposal. However, when handled properly, plastics do little damage to our environment.

Plastics have the advantage that they can be easily reprocessed and recycled. In some cases, one can recover even the raw materials that were originally used in their manufacture. Plastics offer the unique advantage that one can recover the fuel value contained in the hydrocarbon polymer after its use. Plastics can also be made environmentally degradable, especially for packaging applications. There are expectations that in the neat future plastics will be made even biodegradable and compostable so that waste plastics can be3 handled the same way as wet food waste and agricultural waste. The overall eco-friendliness of plastics becomes apparent when one evaluated the total ‘life cycle, namely, an analysis of raw materials, energy, effluents, methods of disposal, etc., of a material from its origin to its final disposal.

*Kothari Research Professor, Jawaharlal Nehru Centre for Advanced Research; Former Professor of Chemical Engineering Director UDCT, Mumbai

** Former Director General, CSIR & Secretary, Department of Scientific Industrial Research (Govt. of India)

We are grateful to Indian Centre for Plastics in the Environment, Mumbai for permitting us to publish an edited version of the article, which was recently published in the form of a message by Eco-Echoes.

This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.

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