Piece polyurethane this may take 450 years in decomposition. About the same for heat-stable polyurethane. Obviously, to solve this serious problem, it is necessary to look for biodegradable plastics. The problem is that it is difficult to achieve the properties of polyurethane that make it so widely used. Plus, many of them are not as biodegradable as they promise. For this reason, an international group of scientists developed self-destructive plastic when you don’t need it anymore.
This is precisely a heat-stable polyurethane, but inside it contains bacterial spores that remain inactive throughout its entire service life, but are activated when plastic is thrown away, contributing to bacterial growth can make it worse.
The ability of certain bacteria to degrade plastic has become one of the greatest discoveries of recent times. The bad news is that we can’t always control where discarded materials end up. Thus, self-destructive plastic solves this problem by carrying its own microorganisms. At the moment it has only been tested in laboratory conditions, but its developers are confident that it can be implemented. industrial scale without much difficulty.
What is thermoplastic polyurethane?
This self-destructive plastic is essentially thermoplastic polyurethane. It is the same material as polyurethane, but the difference is that it can be molded at high temperatures, without the need to create bonds with other chemical additives, as is the case with traditional polyurethane. It is usually used to make shoes, auto parts and smartphone cases, among other uses. But, be that as it may, it matches polyurethane in terms of the difficulty of decomposition after it is thrown away.
Here’s how self-destructive plastic works
To make self-destructive plastic, the study authors began by selecting the ideal bacteria for this purpose. After studying several different species, they were left with Bacillus subtilis for three main reasons. First of all, because his ability decompose plastic This is well known. On the other hand, since his disputes may remain inactive for long periods of time when they lack the moisture and nutrients necessary for bacteria to survive. And finally, because it’s bacteria harmless to humans. In fact, it is commonly found in probiotic products.
Once the bacteria were selected, the temperature needed to be sorted out. Controversy B. subtilis They don’t tolerate heat well and we have already seen that thermoplastic polyurethane requires high temperatures to mold.
For this I know trained spores resist high temperatures. This was achieved by gradually exposing them to increasing temperatures. When they were able to withstand a certain temperature, they warmed up a little. Thus, before reaching 135°С from which this material is cast.
Once the polyurethane and spores were mixed, the self-destructive plastic was ready, but it needed to be tested to see if it could actually degrade as intended. So they took stripes of these materials and were published in the media with different levels of nutrients and moistureand the presence or absence of other bacteria.
It has been observed that under ideal nutrient and humidity conditions, 90% of plastic will decompose in just a few seconds. 5 months. Moreover, there was no longer a need for bacteria. There were enough spores contained in the plastic. In any case, if nutrients and moisture were present, even if they were not at ideal levels, a significant portion of the plastic would also degrade.
Therefore, in any landfill or environment where plastic is disposed of, it will eventually begin to self-destruct.
Unexpected effect
What’s interesting about this self-destructive plastic is that it doesn’t just decompose when it’s thrown away. It has also been proven that spores give greater strength and elasticityas they help stabilize its structure.
All of them are advantages, so these scientists are very optimistic about the future of their invention. It’s not just the messages of detectives in films that self-destruct. The same goes for the plastic we no longer want to use.
Source: Hiper Textual
