Australian chemists report a breakthrough in the efforts to slow down degradation of plastic and also assess the level of degradation at any given point of time.
'What makes this technique unique' says Dr Kathryn Fairfull-Smith from the Queensland University of Technology and member of the Centre of Excellence for Free Radical Chemistry and Biotechnology, Australian Research Council,á'is that we have designed a molecule with two functions. The first is that the molecule begins to glow as the plastic is damaged by free radicals, which themselves form as a result of environmental exposure. The second function is that the mechanism which turns on the 'glow-switch' also acts as a trap for the free radicals so that plastic degradation is retarded.'
The new research published in the American Chemical Society's Journal 'Macromolecules' is more sensitive than current techniques at detecting free radicals that cause changes in the plastic during the initial stages of environmental degradation.
'Just imagine if on your outdoor plastic chair a spot started to glow, it would be a handy warning system that degradation was occurring' Dr Fairfull-Smith said. 'We have been able to replicate a similar situation in the lab with compounds we have purpose-designed so that we can more accurately tell how long a polymer will last.'
The process that causes plastics to become brittle and paintwork to flake is brought about by free radicals, which form following exposure to the sun. 'We can't stop the sun from shining', says Dr Fairfull-Smith, 'however, with our new compound we are able to lock-up the free radicals so that degradation is slowed down and see in real time the damage that is being done.'