Transparent paper could replace plastic in more than one application
October 22, 2009 § 2 Comments
I have to write this one down. I tried so much to find such information when I was writing the article on replacing plastic and metal with translucent ceramics and somehow I missed it, so for future reference I will write about it right now.
We’re used to seeing paper lamp shades that scatter light in a warm way and there is paper with a high degree of translucency – tracing paper – but did you thought that glass-transparent paper is possible? Thought so. Neither did I. Until I have stumbled over this article. The study of scientists at the Kyoto University, Department of Biomaterial Sciences is actually pretty new, published on Feb 3 2009.
The Abstract of the study states the following:
“Optically transparent paper of densely packed cellulose nanofibers is prepared without any additives. This material has the same chemical constituents as conventional paper, the only difference being the fiber width and the size of the interstitial cavities. This optically transparent paper exhibits high Young’s modulus, high strength, ultra low CTE, and high foldability.”
I’ll try to make it short as you can read the long version following the link above. Basically the smaller the cellulose fibres in paper the higher the degree of translucency /transparency is achieved. The method the scientists used was pretty simple 4 steps process:
- They swelled the wood flour bundled cellulose fibres in water and then mechanically grinded them just once, which broke them down into single nanofibres;
- Next step was to filter the nanofibres from suspension, applying pressure to keep them as compact as possible in a sandwitch between wire mesh and filter paper. There is no mention as how much pressure though. This step is essential because otherwise gaps between the nanofibres would form and the light will be scattered in the structure instead of passing through;
- They let it dry for three days. At this stage the paper wasn’t transparent enough and some light was still scattering through the structure making it highly translucent but not transparent;
- The researchers polished the sheets using emery paper, which resulted in truly transparent films with 71.6% light transmittance.
Moreover, the paper proved better mechanical properties than the paper we all know. Dr Masaya Nogi, seemingly the head of the team, says:
“21st-century paper using cellulose nanofibers has high transparency like glass and plastics, high thermal stability like glass, and then high foldability like traditional paper—it’s not only flexible, but it’s foldable.”
I can’t wait to learn more on this apparently “simple” method of obtaining a material that shows such qualities. I can only imagine a few layered such sheets of transparent paper made into different objects such as lampshades. Cover it with an eco-friendly nano-coating (read this article on nano-technology for more information ) for waterproofing and you could make endless objects with it.
Reccomend this to your friends: