It is not only quickly destroyed, but also recycled – a new type of bioplastic can solve the garbage problem on Earth. Here are five of the most promising green materials prototypes.
The fight against plastic pollution is being pursued on several fronts. One of the problems with this material is that it can persist in the environment for a long time, and in some cases even centuries. By changing the manufacturing process of plastic, scientists hope to offer functional forms that decompose quickly, safely and naturally in a short time. And recent discoveries suggest it might be possible in the future.
Most plastics today are made from a chemical derived from petroleum. It is processed to form strong carbon bonds between individual monomers, which combine into long chains to form a polypropylene polymer. Such processes do not occur in nature, therefore it is very difficult for such bonds to disintegrate in the natural habitat.
Much of the research on plastics is focused on new recycling methods that can break these chains more efficiently and allow material to be reused. At the same time, some scientists are striving to create plastic that is completely recyclable, for example, from natural materials and with special enzymes that break down the material after use.
Here are five of the most promising green plastics breakthroughs.
Wood powder bioplastic: decomposes in 3 months
A team from Yale University combined wood powder and biodegradable solvent. As a result, scientists turned sawmill waste into a suspension of organic polymers and cellulose with hydrogen bonds and interweaving at the nanoscale. Then, during the course of the study, the scientists cast the suspension into a bioplast.
After, the scientists conducted an experiment. They dipped sheets of bioplastic into soil, where the molecular bonds began to break down in two weeks, and the samples completely decomposed in three months. The bioplastic also exhibited high mechanical strength, fluid retention stability and UV resistance.
In addition to rapidly degrading, bioplastics can also be returned to their original suspension form. This allows the solvent to be recovered and reused.
The research is published in the journal Nature Sustainability.
Bioplastic from waste: biodegradable in 12 months
Scientists from the Institute of Production Systems and Design Technologies named after Fraunhofer in Germany used industrial waste in the form of fats, which contain a large amount of residual minerals.
In the fermentation chamber, genetically modified bacteria metabolized these minerals into a biopolymer, polyhydroxybutyrate (PHB). Microbes stored it in their cells in liquid form as a source of energy.
After the PHB was subsequently dissolved, scientists mixed it with proprietary chemical additives. With their help, PHB quickly solidified. The result is a bio-derived polyester. The authors of the development have shown that the material exhibits properties similar to those of polypropylene.
Experiments have also shown that if a PHB-based polyester is placed in an ordinary landfill, natural microorganisms will completely destroy it within 6-12 months.
Built-in enzymes decompose material in a few days
Scientists at Berkeley Laboratories have developed a way to embed small amounts of commercial enzymes directly into the plastic itself, so that the material breaks down on its own wherever it goes.
In doing so, the researchers added a four-monomeric random heteropolymer (RHP) to the material to keep the plastic in a stable shape. Its task is to disperse enzymes at a distance of several nanometers from each other.
The result is a plastic that remains stable with regular use, but only begins to break down when it comes into contact with compost soil or hot water. In testing, the team found that soaking the plastic in water at room temperature for three months did not break it down – the process only starts when the temperature rises slightly.
In warmer than usual water, the new plastic is completely destroyed in a few days.
University of California at Berkeley
The team has already applied for a patent for a new degradable plastic and founded a startup to help commercialize it.
Plant-based bioplastic: degrades in 4 years
NEC is also working on forms of sustainable plastic and has created a recipe for a material that is as durable as traditional plastic, but much more environmentally friendly. The new NeCycle material consists of 50% cellulose obtained from inedible plants – wood and straw. The authors of the development note that it can be used for injection molding, like conventional plastics.
NEC has created a new bioplastic in the form of granules or molded components for all types of products.
This gives it the same characteristics as conventional plastics. At the same time, during its creation, fossil resources are not used, and it also does not pollute the natural environment, decomposing in about four years. NEC said it is ready for mass production of NeCycle.
Plastic decays in a week in sunlight
Researchers in China have created a new type of plastic that decomposes in just a week when exposed to sunlight and oxygen.
The new material came about by accident when study author Liang Luo of the China University of Science and Technology Huazhong was working on an improved type of chemical sensor. A materials scientist was developing a new polymer film that changed color depending on the pH level. This process was driven by the unique molecular structure of the material: chains of monomers give the film a dark red color and carry it away when these bonds are broken.
In the course of his team’s experiments, Luo found that the dark red color of the film quickly disappeared, and the material itself decomposed after several days in sunlight. Breaking these bonds is precisely the common goal of plastics processing research.
Plastic is not suitable for use in soda bottles or shopping bags as it decomposes quickly and decomposes completely under exposure to sunlight and air within a week. At the same time, without leaving behind fragments of microplastics that destroy the environment. Where the new plastic comes in handy is in flexible electronics or smartphones – there it will be isolated from air and light for its entire life.