As long as a small amount of polymer chewing enzyme is added to the plastic, plastic bags and plastic forks can be biodegraded to the point of composting!
Experts said: At a moderate temperature, under standard composting conditions, or in ordinary tap water, the plastic film added with enzymes can be decomposed in a few days to weeks.
"Biodegradability is different from composting," said researcher Xu Ting. She often finds some fragments of biodegradable plastics in the compost in the garden.
Most biodegradable plastics will be landfilled, but the landfill conditions are not suitable for degradation, so its degradation speed is not faster than that of ordinary plastics.
Previously, embedding polymer chewing enzyme in biodegradable plastics would accelerate its decomposition. However, the potentially harmful "microplastics" is often formed unintentionally, and this "microplastics" is spread all over the global ecosystem.
If these enzymes gather together and randomly cut off the molecular chain of plastics, resulting in incomplete decomposition and the generation of "microplastics"-it is better not to degrade!
Therefore, in the latest research, in order to solve the above problems, researchers added "separate enzymes" to two kinds of biodegradable plastics (including polylactic acid, which is commonly used in food packaging).
They use the enzyme together with another degradable additive to ensure that the enzyme does not aggregate or disperse.
These isolated enzymes seize the end of the plastic molecular chain and cut off each link like spaghetti, which not only decomposes the plastic, but also prevents the formation of microplastics.
Generally speaking, adding enzymes to plastics will increase the cost and destroy the properties of materials.
However, the new enzyme only accounts for 0.02% of the weight of plastic, and the modified plastic is as strong and flexible as the plastic of ordinary shopping bags.
This technology is not suitable for all plastics for the time being because their molecular structures are different. The R&D team is trying to overcome this limitation, and they have also applied for a patent for this technology.
One of the R&D members started a startup company and intends to commercialize this patent.