Lightweight, durable, and inexpensive plastics are in many ways the ideal materials. This applies at least until they are no longer needed. Because most of the synthetic materials, due to the color and fillers, plasticizers, and other additives are difficult or impossible to recycle. Even the as well recyclable, applicable to plastic, PET is because of additives or other plastic container materials in the collection, only part of which is recycled, the Rest goes in waste incineration plants or landfill.
editor in the Department "nature and science".F. A. Z.
To change this, an attempt is made to modify many of the plastics during the manufacture of chemically so that they are degraded after use, more easily and, if possible, can be reused. Progress in Recycling of composites have been reached, researchers from the Massachusetts Institute of Technology in Cambridge. You have succeeded because of their robustness, estimated plastics in the recyclable versions to convert, without that the properties are lost.
thermosetting plastics materials because of their mechanical strength, durability and heat resistance to the high-performance art. You will be for vehicle and aircraft parts, brake pads, car tyres, safety helmets or for housing electronic equipment used and account for around 20 percent of the produced plastic. However, thermoset resins, including epoxy resins, polyurethanes and vulcanized rubber to be recycled, far more difficult to than other plastics. The chemical bonds linking the polymers closely, are a lot of plastics are stronger than, for example, in the case of the thermal. They are difficult to break. Once cured, can thermosetting plastics be a one-time Heat up again and deformed, softened, and are thus not recyclable. But that could change thanks to the procedure, the mit researchers.
Jeremiah Johnson and his colleagues served on the body parts, the plastic used Polydicyclopentadien (pDCPD), also known under the trade name Metton, as a research object. Prior to polymerization, they are mixed degradable silyl ether monomers. Finely distributed in the Material, the silicon, oxygen and carbon existing molecules attach themselves between the polymer strands and replace the strong covalent bonds between the carbon atoms by weaker Silyl bonds.
Tests showed that the mixed monomers, the physical properties of the cured thermosetting resin modified. When the researchers dipped the plastic, however, in a fluoride-containing solvent, broke the bonds, and the modified Metton dissolved. A white powder remained. The best results, a proportion of the silyl ether delivered monomers of between seven and ten percent, the researchers report in "Nature".
A closed recycling loop
The degraded thermosetting could re-use. The researchers added mixed to the obtained powder of the starting materials used in the pDCPD-synthesis. They received a high quality Material that could be used to process a hard plastic and similar good properties showed as the Original. Now you want to convert with this strategy, other thermosetting plastics in the recyclable materials. This must, however, be the appropriate degradable monomers found the fit similar to the polymers such as silyl ethers to pDCPD.Updated Date: 10 August 2020, 13:19