Can we reuse plastic bottles?
I believe that we can use water bottles, and really everything else we now call trash, as raw materials. What we need is a little ingenuity to see how precisely to get from raw materials to finished product.
My father and I have been bouncing ideas back and forth for months about how we could reuse plastic bottles to build small houses or shelters. The homeless in America, as well as others around the world, could take bottles and other materials out of landfills and use them to build shelters.
This kid has exactly the same idea. And while that dome isn't made from reused products, in principle other domes could be made by reusing trash more like this guy.
The last chapter (chapter 26) of my Organic Chemistry book is on Synthetic Polymers. The plastic bottles are made of polyethylene. "At low temperatures, long-chain polymers are glasses." If we subject them to stresses, they will tend to be rigid and inflexible, shock force will cause fractures.
The material is not malleable nor is it ductile at room temperatures. When the material is heated beyond its glass transition temperature and into its thermoplastic phase it does achieve malleability. If the material is heated further to its crystalline melting temperature then it achieves malleability and ductility.
"A determination of the softening point for materials such as polyethylene, which have no definite melting point. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 sq. mm circular or square cross-section, under a 1000-gm load. Also known as Vicat softening temperature.
Definition Copyright ©1989 CRC Press LLC. All rights reserved."
The plastic bottles are a kind of Low-Density polyethylene. Low density corresponds to less conformity to a crystalline structure and so is less rigid. There is a Google Book that reports on the physical properties of various chemicals, and determines the vicat softening temperature for LDPE (Low-Density PolyEthylene) to be between 80 and 98 degrees Celsius.
But what is important is that malleability, which is "being capable of being pounded into sheets", does not occur at the vicat softening temperature. The result is that one bottle can be deformed and manipulated, but not joined to another bottle on a chemical level the way a metal can be.
For these reasons, I believe the best results for reusing plastic bottles do not come from chemistry, but from engineering cuts and folds on the bottles. I think the best structure that can be built by reusing plastic bottles will not attempt to melt down or smash or chemistry the bottles. It will come from the engineer who has the most experience with oragami.
