The advantages of degradable polymer materials

In the world, millions of tons of waste plastics are discarded each year, and most of them are thrown directly into the ocean. Some plastic waste that has not been thrown into the ocean has formed white pollution on land.

Many people think that plastic waste will eventually decompose, but this decomposition may take 50 years, which is beyond people's expectations. During this long period of 50 years, many rubbish accumulates on the oceans and land. In particular, plastic garbage floats on the surface of the sea. It is mistaken for sea lice and other foods by marine animals, thus causing ecological imbalances. A large number of plastic fishing tackles that are thrown into the ocean each year will wrap marine animals in it, which is another hazard.

In order to reduce the risk of plastic waste, people first think of using non-polluting (decomposing) packaging materials instead of plastic, and using benign and safe utensils instead of white plastic utensils.

People first thought of returning to nature, and paper was the earliest packaging material used. However, papermaking requires the consumption of large amounts of wood, which results in the loss of forests that were previously insufficient and reduce the earth's vegetation. In addition, the most vexing thing is that the modern paper industry is a big polluter. It is no less than plastic waste that causes pollution to rivers and lakes. Therefore, today’s people of insight believe that paper packaging and paper should not be strongly promoted. Tableware.

Some chemists focus on the use of starch to make packaging materials and cutlery. The advantages of starch are: 1 It is non-toxic; 2 The raw materials for making starch are from agriculture, rich in resources and low in price; 3 Starch is a kind of easily degradable The compound can be degraded by the process shown in the figure below. The final product is non-toxic, harmless, and highly safe glucose.

Degradation of starch

Of course, chemists still have not given up on the plastic itself to take measures to reduce environmental pollution. Plastics are made from macromolecule compounds, which themselves are long chain molecules composed of repeating groups. Chemists have found ways to change the structure of macromolecules and make them easily degradable.

One method is to add a photosensitizing group between a certain distance of the molecular chain of the polymer compound, and they are exposed to sunlight. The photoactive group absorbs radiation to break the polymer compound, and fragments after breaking are relatively easy. Biodegradable. The specific approach is to add keto groups to high polymers (such as the most common plastics such as polypropylene, polyethylene, etc.) to produce keto-generation polymers that will undergo photolysis under sunlight irradiation.

Another method is to introduce some groups into the polymer compound to make it suitable for the taste of certain microorganisms. These microorganisms can break the long-chain molecules of the polymer compound into small pieces, and it is easier to further degrade the small pieces.