Foam polystyrene has been made biodegradable through a novel approach by Chinese scientists. The team has now developed a new approach that involves embedding water-absorbing resin particles about five micromeres in diameter throughout a chemical like styrene before it is polymerised to form a polystyrene-like material. When the resulting solid comes into contact with water, the resin particles expand, reducing the polymer structure to a powder that should then biodegrade. The team says that by altering the ratio of ingredients, it is also possible to control the rate of disintegration. A crucial factor, the scientists say, is that the resulting foamed polystyrene is cheaper than conventional materials and should therefore be readily adopted by cost-conscious companies that also want to be environmentally responsible.
Foam polystyrene, used as a protective packaging, is not biodegradable. Previously manufacturers have tried making it more environmentally friendly by incorporating cellulose and starch, which microbes can break down, or by adding light-sensitive polymers that degrade in sunlight.