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| CSIRO | SOLVE | Issue 8 | Aug 06 | |
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ARTICLE
PLASTICS:
Plastics and Wood Get the 'Slip, Slop, Slap' By Rebecca Thyer
Most Australians are well aware of how damaging the sun’s rays can be – the Cancer Council’s ‘slip, slop, slap’ campaign encouraging the use of protective clothing and sunscreen is now a national summer mantra. But it is not only our skin that suffers from too much sun. Timber-clad houses and furniture, as well as plastic car and boat fittings, are also quick to show the effects of damaging ultraviolet (UV) rays. Finding a ‘sunscreen’ or protective coating suitable for plastics or timber products is now being addressed by researchers at CSIRO Manufacturing and Materials Technology (CMMT). Through a project co-funded by CSIRO and the Forest and Wood Products Research and Development Corporation (FWPRDC), the CMMT team aims initially to develop functional coatings for softwoods. CMMT’s Dr Voytek Gutowski says UV damage is a worldwide problem, leading to polymeric (plastic) and timber products deteriorating and requiring ongoing maintenance. He says the team is working on developing a dual-purpose coating that gives UV and moisture protection. “Through our research we are verifying new concepts and observing interesting and promising properties from functional nanomaterials we are developing,” Dr Gutowski says. CSIRO’s extensive experience in materials science is a key to the project succeeding. “Our understanding of materials’ properties and UV radiation’s effect on polymers helps us to comprehend what the destructive factors are, while our knowledge of specific types of functional nanomaterials is helping us to create an interceptive multifunctional barrier.” When polymers – both synthetic and natural – are exposed to UV radiation they undergo oxidation, which causes mechanical property breakdown, discolouration and surface degradation. Radiation in the wavelength range of 280–400 nanometres has the most damaging effect, with UV-B radiation (280–320nm) causing a wide variety of chemical bonds to cleave, leading to severe polymer mechanical property damage and discolouration. UV-A radiation (320–400nm), related to outdoor and glass-filtered UV exposure of furniture, causes less severe mechanical damage but still leads to surface discolouration. The most effective protection method, Dr Gutowski says, is to absorb all radiation in the UV range, which is what existing protective products aspire to do. However, they only absorb radiation from a certain part of the UV spectrum – about 280–380nm. CSIRO research aims to close this gap and absorb all rays in the UV spectrum. “Our nanofunctional materials, which are still under development, would effectively absorb the whole spectrum of UV radiation. They could, for example, extend the life of outdoor products or extend the time-span between house repainting.”
Dr Gutowski says these specialty materials could also be applicable to a range of other products and materials, and not just timber. “Once initial work is done, our nanofunctional materials and the coatings based on them could be used in any other product exposed to solar radiation, like plastic materials.” For further information contact: |
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