The recycling rate of 8.2 billion tons of plastic manufactured by human beings is only 30%
according to the voice of economics world company, the industrial ecology team of the University of California estimated the total amount of plastic available on the earth. Since several 10 subsidiaries under 6 were invented five years ago, human beings have produced about 8.3 billion tons of plastic. How much does it weigh? It is equivalent to 25000 Empire State buildings in New York and the sum of 1billion elephants, including plastic bottles, plastic bags and other plastic products
plastic was invented by American Baekeland in 1909. He used phenol and formaldehyde to synthesize phenolic resin. Plastic is a kind of high molecular compound, which can change its composition and shape freely. It has the advantages of impact resistance, wear resistance, good insulation and low cost, but its disadvantages are also obvious, and it is difficult to recycle by classification. According to the estimation of the California scientists' team, only 30% of the plastic is recycled, while 70% of the plastic becomes garbage, most of which is buried under the land, and a large amount of garbage floats in the sea
which plastics can be recycled? Professor donglijie, School of materials, Wuhan University of technology, explained this
donglijie: "hot plastics can be formed after melting. It is easy to recycle them. As long as they are purified, sorted and classified in the early stage, and then put into the same conditions, they can still make new products. For example, plastic bottles, plastic tubes and films, there are a large number of them."
it is not difficult to achieve technically. Why is the recycling rate only 30%
donglijie taught that the size stability is good "With regard to the recycling of plastics, the recycling system for plastic bottles is relatively perfect. Now some enterprises are using waste plastics. Others are using leftover materials from the production of products. If they can be used in large quantities, the same thing must be done easily. The world's major raw materials are easy to recycle and can be fully reused. However, the forming conditions of different materials are different. If they are not of the same kind, it is difficult to use them together. In the plastic industry Industry, we are still very concerned about recycling. After all, the source of plastic is oil. We hope to reuse it as much as possible. If we want to expand the coverage of plastic recycling, we need to establish some corresponding mechanisms. In many countries, there will be a strict classification of the packaging materials, which will be divided by different families according to different types, which will increase its recycling rate. "
at present, garbage collection and classification in China mostly rely on roadside waste collection and garbage disposal individuals. Is there a problem of low efficiency
professor donglijie: "it is neither high nor low enough. Many plastics look the same, but they are actually different types. If they are mixed together, the production process of some products may not be very suitable."
70% of plastics become garbage. What is the degradation of plastics in land and sea water? How long will it take
professor donglijie: "Plastic products that have not been completely separated may be incinerated and landfilled. If incinerated, problems such as gas generation and heat generation will certainly occur. Landfilling is not a very ideal way, because long-term landfilling is also a problem for the land. Most non degradable plastics have a long life, and they may not be bad in the soil for 50 or 100 years. There is no way to define plastics that enter the sea: the increase in lining heating thickness and Ratio decomposition of initial lining thickness. Seawater environment for such general plastics, some academic articles will mention that some plastics may become small particles for a long time, but for many plastics, their existence period is still very long. The seawater environment will change a little compared with our current water quality, but it is not extreme. For example, strong acidity or alkalinity will help the degradation of materials. The degradation of some membrane like materials requires high energy, so it is difficult. "
some people once made plastic the greatest material science invention in the 20th century, but now the team of scientists believes that plastic will become a burden on the earth. The total weight of plastic on the earth will exceed 12billion tons in 2050
professor donglijie said: "We never think what it will do to the earth. In fact, it is our use of plastic. For example, how can we recycle it and maximize its use as much as possible. There are many countries in the world, the most typical one is Japan, which will establish a perfect recycling system. For everyone who makes materials, any material is a very valuable resource. The only problem is how to use it."