We all know that plastics are non-degradable, and plastics has always been a topic of concern to environmental figures. The following is the cause of pollution of ordinary plastics, the difficulties of plastic recycling, the performance and structure of degradable plastics, and the application prospects.
Traditional Plastic Pollution Solutions
Ordinary plastics have the characteristics of light weight, good processability, low heat fusion, low energy consumption, safety and non-toxicity, low cost, convenient and comfortable use, etc., and become an effective substitute for ordinary glass, ceramics, steel and paper materials. overused and discarded. Ordinary plastics cannot be directly swallowed by microorganisms due to their molecular weight as high as hundreds of thousands. In the natural environment, it takes hundreds of years to gradually degrade into small molecules, which are eventually decomposed into carbon dioxide and water by microorganisms. If they are discarded in the ocean, they will be decomposed. The time will be longer, it will take four or five hundred years to degrade. In this case, can the problem of plastic pollution be solved through recycling? Recycling is a good measure, but the production cost of recycling exceeds the value of the plastic itself. For single-use plastic products, the direct use of biodegradable plastic is the ultimate means.
Degradable plastic properties and structure
Traditional plastics have a simple hydrocarbon structure and a huge molecular weight. The molecular weight of polyethylene, a common material for plastic bags, often exceeds several hundred thousand, and the structure is stable, but it is difficult to be degraded by microorganisms, and it is easy to pollute the environment if discarded at will. The structure of biodegradable plastics is quite different from the hydrocarbon structure of traditional plastics. It contains various heteroatoms (oxygen, nitrogen), which can be digested and decomposed by microorganisms.
The currently synthesized degradable polymer materials have a large number of ester bonds, which can be hydrolyzed in the presence of water, or digested and utilized by microorganisms, and finally decomposed into small molecules, which will not pollute the environment. The degradation process is not long, and it can be accepted. Scientists have long realized the problem of pollution caused by the refractory degradation of traditional plastics, and have been looking for solutions for plastic degradation. From ordinary synthetic plastics to photodegradable plastics, to oxidatively degradable plastics, and finally to biodegradable plastics developed in recent years, the problem of plastic degradation has been truly solved.
Application prospect
The harmlessness of biodegradable plastics is its most significant advantage, avoiding microplastic pollution that may occur with traditional plastics, and is harmless to animals and humans. The large-scale replacement of traditional plastics by biodegradable plastics will effectively alleviate the problem of white pollution in the future, and even make the phenomenon of plastic pollution disappear completely on the earth.
