Aluminum has been used as a lightweight alternative to steel but it is held back by its higher market price.
Now scientists have created a transparent polythene film that is stronger than aluminum but a fraction of the weight. The lightweight, transparent plastic sheet with mechanical strength of aluminum could find use in glazing, windscreens, visors and displays. It could be an ideal replacement for traditional and polymeric glass in many applications.
Transparent plastic sheet is optimal balance between strength and transparency
The team of researchers from the Queen Mary University of London, University of Warwick (U.K.), Nanoforce Technology Ltd (U.K.) and Eindhoven University of Technology (the Netherlands) devised a processing technique by carefully selecting high-density polyethylene film and tuning the temperature between 90° and 110° C to yield highly oriented polyethylene films with a transparency of 90% in the visible range.
The lightweight transparent film has strength exceeding that of metals
The transparent films possess a maximum resilience or Young’s Modulus of 27GPa and a maximum tensile strength of 800MPa along the drawing direction; both are more than 10 times higher than those of polycarbonate and poly (methyl methacrylate).
For comparison, aluminum has a Young’s Modulus of 69GPa and aerospace-grade aluminum alloy can have tensile strengths up to around 500MPa. While film has a density of less than 1000kg/m3, aluminum has a density of around 2700kg/m3 which means these high strength transparent polymer films can outperform such metal materials on weight basis.