Polystyrene: a green material
“Nature is not a place to visit. It's our home.”Gray Snyder
POLYSTYRENE:
Polystyrene can be defined as an environmentally friendly material throughout its life cycle. It consists of polystyrene granules, a thermoplastic resin obtained from three consecutive processes:
The synthesis of ethylene and benzene which produces ethylbenzene;
The hydrogenation of ethylbenzene which produces styrene;
The polymerization of styrene which produces polystyrene.
In the polymerization process an expanding agent is dissolved, generally pentane, in addition to other additives which add or enhance the qualities of the material, such as polymeric flame retardants for self-extinguishing or graphite to enhance its insulating capacity.
Its salient features can thus be summarized:
It consists of 98% of air and therefore uses as an integral part a renewable and clean raw material, to which is added only 2% of pentane, or non-renewable fossil resources;
It maintains its characteristics unchanged over time, being resistant to external agents such as bacteria and mold, with a high resistance to impacts;
It is ductile and light, allowing it to find various uses in the packaging sector or in any context in which it is desired to protect and isolate with the lowest weight incidence and maximum performance (think about the inside part of a helmet or a baby seat for car);
It is not water-soluble and therefore does not release any substance harmful to the environment or to human health, so it is one of the privileged materials for contact with food substances;
It is a powerful insulator, used in all the contexts in which this is necessary, from building to controlled temperature transport or food and pharmaceutical fields;
It is 100% recyclable an infinite number of times and when this is no longer possible, it can be used for heat generation, with performance comparable to fuel oil, finding use in the production of electricity.
Regarding recycling, this can be done with various methods.
The recuperated polystyrene can be ground and introduced into a special extruder, mixing it with virgin material in different percentages which depend on the type of finished granulate to be obtained, or the expanding agent can be recovered for use in the light hydrocarbon-based solvent market.
Another possibility is to reduce it again in pearls, always mixing it with a percentage of virgin material depending on the density and the compressive strength to be obtained, then recompact it to insert it again in the production cycle. Finally, once in pearls, it can be used in the building sector .
