AUSTRALIAN chemists have devised a novel way to see the level of damage plastic has suffered from environmental exposure by making it glow.
What makes the technique unique, according to Dr Kathryn Fairfull-Smith from the Queensland University of Technology and member of the ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, is the design of 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,” Fairfull-Smith said.
“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 this week 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,” she continued.
“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”, she said, “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.”