Why use fully biodegradable plastics?

Degradable plastics refer to plastics that can be degraded by themselves under natural conditions, and are generally divided into four categories: photodegradable plastics, biodegradable plastics, photo-biodegradable plastics, and water-degradable plastics. Although the above-mentioned degradable plastics are all environmentally friendly, there are still big differences in technical costs and actual operation. For example, photodegradable plastics are made by adding photosensitizers to the plastic, which gradually decomposes the plastic under sunlight. It belongs to the earlier generation of degradable plastics, but its disadvantage is that the degradation time is difficult to predict due to sunlight and climate change, so the degradation time cannot be controlled. Similarly, polyethylene photodegradable plastics synthesized with ethylene and CO as raw materials will be degraded into small molecules or decomposed by microorganisms after a certain period of time under certain conditions, overcoming the shortcomings of difficult to decompose and difficult to decay. However, due to the high cost of producing this degradable plastic, it is not possible to promote the use of this kind of degradable plastic in a large area. Biodegradable plastics can be almost completely decomposed by bacteria, fungi, algae and other microorganisms in nature, participate in the carbon cycle in nature, and are divided into incomplete biodegradable plastics and fully biodegradable plastics (or fully biodegradable plastics). In the preparation process of incomplete biodegradable plastics, starch is often used to modify (or fill) PE, PP, PVC and other common plastic products, such as starch-based plastics, cellulose-based plastics and protein-based plastics. Fully biodegradable plastics are mainly biodegradable plastic products made of natural polymers (starch, cellulose, chitin, etc.) or agricultural and sideline products after microbial fermentation. Aliphatic polyester, polylactic acid, etc. are all such plastics. This kind of plastic can be completely degraded by microorganisms, and because of the addition of starch, PVA and other substances with good compatibility, its performance is close to or even better than that of ordinary plastics. Biodegradable plastics can be degraded by the environment to meet people's expectations. These two types of materials will not cause serious pollution to environmental culture after degradation, and the production of fully biodegradable plastics does not require petroleum, and the degradation is more complete.