Plastics made fireproof thanks to mother-of-pearl mimic

It’s a technicolour dreamcoat for your crisp packet – a strong, flame-retardant and airtight new material that mimics mother of pearl. The natural version, also called nacre, is found on the inner shell of some molluscs, where it is built up of layers of the mineral aragonite separated by organic polymers such as chitin. It is remarkably strong, without being brittle or dense. We would like to use nacre and similar materials as a protective coating in many situations. However, making them is a slow and delicate process that is difficult to recreate at any useful scale. Artificial nacre-like materials are usually painstakingly built up layer by layer, but Luyi Sun at the University of Connecticut in Storrs and his colleagues found a way to do it all in one go. With their quick method, they were able to make their thin film coating 60 per cent stronger than stainless steel. A plastic sheet covered in the material was over 13,000 times less permeable to air and other gases than it was on its own. When the team tried to set it on fire, it became scorched where the flame directly touched the coated sheet, but would not ignite. To form the film, the researchers mixed a type of clay th...

Plastic light diffusion systems match LED lighting needs (MAGAZINE) (UPDATED)

Gabi Bar and Moira Nir explain how to select thermoplastic compounds for SSL optical systems and how to measure the important transmission and diffusion parameters. GABI BAR and MOIRA NIR explain how to select thermoplastic compounds for SSL optical systems and how to measure the important transmission and diffusion parameters. In recent years, lighting manufacturers and developers have moved away from traditional light sources and to LED-based solid-state lighting (SSL) technology. While LEDs offer many benefits such as excellent energy efficiency, the point sources also present some problems in general-illumination applications – glare, for instance. So in LED lighting developments, engineers must design lens systems and covers that are optimized in terms of their light diffusion properties to eliminate the LED glare issue. Glass and transparent plastics, especially acrylic resins, have long been used in the lighting industry for various aesthetic and functional purposes in optics design. But as the lighting market moves increasingly to LED technology, requirements for high light diffusion have spurred lens and cover manufacturers to devote much of their activity to dev...