Polystyrene, a monomer of styrene, is a brittle, clear, and hard solid plastic. The astounding physical and chemical properties possessed by polystyrene is the reason behind its use in almost every industry. The high thermal insulation property, strength, durability, resistance towards water, weather, and microorganism makes it an ideal product for various uses. Being a thermoplastic polymer, polystyrene is solid at room temperature and if heated, it can turn to a liquid state. Hence it can be mold to any fine structures. Polystyrene is either solid or foam structure which is known as Expanded polystyrene (EPS). Polystyrene is a naturally transparent plastic but can be colored using colorants.
Because of its high thermal insulation property, polystyrene is most commonly used for the packaging of food and other sophisticated electronic equipment. It is also used in making disposable cutleries, sculptures, containers, lids, trays, bottles, etc. In the construction industry, polystyrene is used for landscaping, parapets, etc. The high resistivity towards weather conditions and microorganism makes polystyrene ideal for horticulture as well. Being an inexpensive polymer, it is also used for decoration purposes.
Though polystyrene possesses numerous properties, they are considered to be non-biodegradable. The resistivity towards almost everything makes it non-degradable in nature. This can cause several environmental impacts. Since it takes hundreds of years to degrade, they can fill the spaces. The major impact of thrown out polystyrene is for the animals. They mistake it as food and are consumed which causes serious health issues. Polystyrene foams float over water and blow in the air which is said to have a serious effect on the birds and the marine animals. Polystyrene when burnt releases toxic chemicals which can pollute the air to a great extent. Hence the studies show that they are ideal to reuse or recycle rather than left unused.
Benefits of recycling polystyrene
A large quantity of polystyrene is disposed of every day. Recycling polystyrene can benefit the environment as well as the economy. The major benefits of recycling polystyrene are
Reduce litter – The recycling of polystyrene can reduce landfilling and floating oversea which can help save animals.
Reduced size and space occupied – On recycling, polystyrene reduces its size by 95% and hence requires only less space.
Reduce carbon footprints – Being a monomer of styrene, which is manufactured from petroleum, recycling of polystyrene reduces carbon footprints. It can also save the limited availability of non-renewable resources.
Economic benefits – The increase in the demand for polystyrene can economically benefit the recycling business.
Methods for effectively recycling of polystyrene
Not every polystyrene is recycled. Only certain types of polystyrene are accepted for recycling. This includes Expanded Polystyrene (EPS), High Impact Polystyrene (HIPS), Oriented Polystyrene (OPS), Styrofoam, post-consumer, and post-industrial products. The three methods of recycling are:
Shredding
In this method, the Expanded Polystyrene (EPS) to be recycled is fed to a foam shredder where it will be shredded to small beads of 5- 10mm in diameter. These shredded beads are used as fillings in bean bags, cushions, toys, stuffed animals, etc. Shredding the foam eases the recycling process and at the same time produces a recyclable product of high value. The shredded beads can also be mixed with new beads to make new products.
Compacting
In this method, the EPS foam to be recycled is fed to a compactor where it will be compressed, crushing out the excess air. Compacting reduces the volume of the scrap EPS by 98%. After compacting, foam logs are given out which can be stacked and stored at any size. The recycled foam logs can be reused to make other products like pots, frames, furniture, etc. Because the foam logs weigh comparatively lesser than the scrap, they could be easily transported. By the method of compacting, the size can be reduced to one-fourth of the original EPS which helps in eliminating landfills to an extent.
Melting
In this method, the scrap EPS is fed through a palletizing extruder in which they are melted by applying heat. The molten EPS is cooled resulting in the solidification of the product. The solidified end result is then re-melted to make products like cloth hangers, DVD cases, etc.
Polystyrene is a commonly used product in every industry. Hence the level of wastage will also be high. This can have a serious impact on environmental stability. Since polystyrene is composed of 98% air, CFC is not emitted on recycling, adding no harm to global warming. Polystyrene is also widely reused in urban areas for horticulture. Because of the lack of land and the fluctuating weather conditions they can be used for growing plants. Polystyrene in an Eco-friendly substance but the overproduction of the EPS can do harm as well. To avoid such harm, it is ideal to recycle and reuse.
