University of Warwick research team develop technique to make transparent polythene films as strong as aluminium

A research team based at the University of Warwick has devised a processing technique that can create transparent polythene film that can be as strong as aluminium but at a fraction of the cost.

The material has the ability to be used in glazing, windscreens, visors and displays in ways that add strength and resilience while reducing weight.

Previously, anyone looking to replace heavy and often brittle glasses with a transparent plastic have looked at conventional transparent plastics like PC and PMMA, both of which possess relatively unsatisfactory mechanical performance compared to an engineering material like aluminium.

The researchers took HDPE polythene sheets and drew out these sheets at a range of temperatures below the melting temperature of HDPE.

By tuning the drawing temperature they could achieve a transparency of 90 per cent in the visible range.

However, the best balance between strength and transparency was achieved at drawing temperatures between 90 and 110°C.

Professor Ton Peijs of WMG at the University of Warwick, said: “We expect greater polymer chair mobility at these high drawing temperatures to be responsible for creating fewer defects in the dawn films, resulting in less light scattering by defects and therefore a higher clarity."

“Our results showed that a wide processing window ranging from 90 to 110°C can be used to tailor the required balance between optical and mechanical performance.”

“It is anticipated that these lightweight, low-cost, highly transparent, high strength and high stiffness HDPE films can be used in laminates and laminated composites, replacing or strengthening traditional inorganic or polymeric glass for applications in automotive glazing, buildings, windshields, visors and displays.”