Creating sustainable paint from recycled plastic

via University of Sheffield

  • Experts have managed to mimic the colour of the Cyphochilus beetle’s scales one of the brightest whites in nature
  • Findings show the colour is created by the structure of the beetles’ scales, not by pigments and dyes
  • By managing to replicate this structure in the lab using plastic, researchers hope to pave the way for sustainable, ultra-white paints made from recycled plastic waste
  • New paints would have a much lower carbon footprint and help tackle the challenge of recycling single-use plastics

Cyphochilus beetle scales are one of the brightest whites in nature and their ultra-white appearance is created by the nanostructure in their tiny scales, as opposed to the use of pigment or dyes.

Experts have now been able to recreate and improve on this structure in the lab using low cost materials – via a technique which could be used as a sustainable alternative to titanium dioxide in white paint.

Dr Andrew Parnell, from the University of Sheffield’s Department of Physics and Astronomy, who led the research, said: “In the natural world, whiteness is usually created by a foamy, Swiss cheese-like structure made of a solid interconnected network and air. Until now, how these structures form and develop and how they have evolved light-scattering properties has remained a mystery.

“Having understood these structures we were able to take plastic and structure it in the same way. Ideally, we could recycle plastic waste that would normally be burnt or sent to landfill, structure it just like the beetle scale and then use it to make super white paint. This would make paint with a much lower carbon footprint and help tackle the challenge of recycling single-use plastics.”

The findings show that the foamy structure of the beetles’ scales had the right proportion of empty spaces, which optimise the scattering of light – creating the ultra-white colouring.

Conventional white paint contains nanoparticles of titanium dioxide, which scatter light very strongly. However, the use of titanium dioxide is harmful to the environment as it contributes to nearly 75 per cent of the carbon footprint of each tin of paint that is produced.

To measure the tiny individual beetle scales, researchers used a technique called X-ray tomography, which is similar to a CT scan but on a miniscule scale. The scientists used the X-ray imaging facilities at the instrument ID16B at the European Synchrotron Research Facility (ESRF) in Grenoble, France.

The intense X-ray source at the ESRF meant whole intact scales could be measured, which was pivotal to understanding them and modelling how they scatter light. To follow how the synthetic material formed, they again used the ESRF to confirm the formation mechanism as the layer dried and became structured.

Dr Stephanie Burg, a PhD researcher at the University of Sheffield said: “This research answers long-standing questions about how the structure inside these scales actually form and we hope these lessons from nature will help inform the future of sustainable manufacturing for paint.”

Learn more: Beetle scales hold secret to creating sustainable paint from recycled plastic, research shows

 

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Turning waste CO2 into plastics

via Chemistry World

Researchers at the Energy Safety Research Institute (ESRI) at Swansea University have found a way of converting waste carbon dioxide into a molecule that forms the basis of making plastics

Researchers at the Energy Safety Research Institute (ESRI) at Swansea University have found a way of converting waste carbon dioxide into a molecule that forms the basis of making plastics. The potential of using global ethylene derived from carbon dioxide (CO2) is huge, utilising half a billion tonnes of the carbon emitted each year and offsetting global carbon emissions.

Dr Enrico Andreoli heads the CO2 utilisation group at ESRI. He said: “carbon dioxide is responsible for much of the damage caused to our environment. Considerable research focuses on capturing and storing harmful carbon dioxide emissions. But an alternative to expensive long-term storage is to use the captured CO2 as a resource to make useful materials.

That’s why at Swansea we have converted waste carbon dioxide into a molecule called ethylene. Ethylene is one of the most widely used molecules in the chemical industry and is the starting material in the manufacture of detergents, synthetic lubricants, and the vast majority of plastics like polyethylene, polystyrene, and polyvinyl chloride essential to modern society.”

Dr Andreoli said: “Currently, ethylene is produced at a very high temperature by steam from oils cracking. We need to find alternative ways of producing it before we run out of oil.”

The CO2 utilisation group uses CO2, water and green electricity to generate a sustainable ethylene at room temperature. Central to this process is a new catalyst – a material engineered to speed up the formation of ethylene. Dr Andreoli explained: “We have demonstrated that copper and a polyamide additive can be combined to make an excellent catalyst for CO2 utilisation. The polyamide doubles the efficiency of ethylene formation achieving one of the highest rates of conversion ever recorded in standard bicarbonate water solutions.”

The CO2 utilisation group worked in collaboration with the University of Nebraska-Lincoln and the European Synchrotron Research Facility in Grenoble in the formation of the catalyst.

Dr Andreoli concluded: “The potential of using CO2 for making everyday materials is huge, and would certainly benefit large-scale producers. We are now actively looking for industrial partners interested in helping take this globally-relevant, 21st century technology forward.”

Learn more: Swansea scientists discover greener way of making plastics

 

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