Resources and environment are the major problems of sustainable development in the 21st century. Biotechnology will become one of the key technologies to solve this problem. Among the many factors that cause environmental pollution, the public hazards caused by plastic waste have aroused extensive attention of the society.
At present, the main countries producing degradable plastics in the world include the United States, Japan, Germany, Italy, Israel and Canada, etc. the varieties include photodegradation, photodegradation, disintegration biodegradation, complete biodegradation and so on.
Biodegradable plastics refer to the plastics that can be decomposed by microorganisms in the soil. With the help of bacteria or their hydrolytic enzymes, the materials can be decomposed into carbon dioxide, water, honeycomb porous materials and salts. They can be completely decomposed and re-enter the biosphere after further microbial action, which is a hot spot of research and development in various countries. Therefore, biodegradable plastics generally refer to the new plastics with certain mechanical strength and can be completely or partially decomposed by microorganisms (such as bacteria, mold and algae) in the natural environment without causing environmental pollution. The mechanism of biodegradation is that bacteria or their hydrolases decompose high molecular weight polymers into small molecular weight fragments, which are further decomposed into carbon dioxide and water by bacteria.
As for degradable materials, a variety of products have been developed and produced
Firstly, degradable resin and masterbatch include total biodegradable resin, photo biological dual degradation masterbatch and composite degradation masterbatch.
Second, degradable plastic products include compost bags, garbage bags, shopping bags, electronic packaging bags, plastic films, catering appliances, golf pins and foam materials.
Third, ordinary plastic products include shopping bags, garbage bags and office supplies.
Biodegradable plastics are mainly used in agriculture, food packaging, degradable foam net and disposable fast food box.
Agricultural plastic film is one of the three pillar products in agricultural production (chemical fertilizer, pesticide, agricultural film), which was originally controlled by the state, and has been in short supply in the market. Since 1979, the cultivation technology of agricultural film mulching has been vigorously promoted in China. In 1980, the area covered by agricultural film was only 25000 mu, and in 1992 it reached 50 million mu. The application of agricultural film has developed from cotton and vegetables to economic crops, such as peanut, melon, sugar beet, sugarcane, tobacco, fruit and food crops, rice, early rice, wheat, corn and so on. The popularization and popularization of agricultural film has achieved obvious economic benefits. According to statistics, the yield increase benefit of agricultural film was 7.1 billion yuan from 1982 to 1987; from 1978 to 1989, the cumulative increase of 28 billion kg of grain and economic crops was achieved by plastic film mulching cultivation technology. From the above statistics, we can see that the popularization and application of agricultural film has brought very significant economic benefits.
In a word, the most prominent advantage of degradable plastics is that they can be degraded and do not pollute the environment. It is an inevitable trend for the development of plastics such as polyethylene, and the upgrading of plastic film products is also imperative. It is predicted that the current market size will reach 30 billion yuan, and the annual growth rate will be 30% - 50%.
