Technology

Extir FL3000 sustainable expanded polystyrene

 By Michela Bellettato

In Italy, you say goodbye to summer by ripping the packaging off six bottles of prosecco and putting them in the fridge. You welcome your friends with tubs of home-made ice cream when they arrive, and invite in the three nice builders doing the winter insulation on the front extension. Then a recycling-obsessed friend starts slating the packaging on the wine and ice cream, and badgers the builders, asking them to leave her aside some cuts from the insulating panels

The group bend their ears to her as the latest chart-topper plays in the background. She tells you how fun and handy it is turning pieces of polystyrene like these into coasters, pots, big letters and Christmas decorations. But she says that mostly, when she’s cutting up, covering and painting those light, plain offcuts, she’s thinking about where they’ve come from. Expanded polystyrene (EPS) , commonly known as styrofoam, is made, as its name suggests, by polymerising styrene. This involves making a chain of molecules of styrene, produced by processing petroleum products. Styrene is a transparent oil which is heated to accelerate its polymerization, a spontaneous reaction that releases heat. Another way of making polystyrene is to suspend styrene in water, combined with a little of a substance that makes the polymer form, then separate and dry as little balls.

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A model of the styrene molecule (Ben Mills, Wikimedia)

But what makes them so characteristically light is pentane, a hydrocarbon that gets embedded in the polystyrene balls when they form in the water suspension. Heat, in the form of water vapour, makes the pentane evaporate, and the particles in turn expand, softening and swelling at the same time the plastic. The balls get 60 times bigger as a result, and every successive cycle of vaporising and emptying welds them together, creating a desired shape based on the mould in which they have been placed. Thanks to its lightness, resistance to shock, thermal insulation and eco-friendly nature, EPS can be used as packaging or insulating material.

Versatility of polystyrene

Of course, it can be difficult picking up the little flecks that often break off its broken edges. At its plant in Mantua, Eni’s chemical company Versalis has developed a kind of styrofoam, Extir® FL 3000, that not only does not release single balls, the minor use of the expanding agent translates into lower emissions and energy consumption. For certain applications, the product can be reused several times. Back at the party, the crusader for creative recycling has got some bubbly down her throat and is explaining that, if you want to make an object recyclable, it needs to be designed and produced specifically with re-use in mind.

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A container made of Extir® FL 3000

Its life before and after use should not be divided, but unified through a circular mechanism. Setting down her glass, your friend explains how expanded polystyrene, being a resin that’s already completely re-usable, can be ground up and mixed with new balls to produce other objects, or even added as light filler to mortar. It can be transformed into compact polystyrene for moulding coat hangers, among other things, or used to recover energy. A wistful goodbye to the days of summer is lightened by the cheery company with their foaming glasses, not to mention the 98% of air contained by the expanded polystyrene.

READ MORE: Recycling football fields by Livia Formisani

about the author
Michela Bellettato
Geologist, from atoms to stars through the Earth