The degradation principle of biodegradable plastics
Biodegradable plastics generally meet the requirements for physical properties of traditional plastics and can be widely used in daily necessities, commercial, and industrial fields. The main reason is that biodegradable plastics are more environmentally friendly materials than traditional plastics, which can alleviate problems such as plastic pollution and resource waste, and reduce the negative impact of humans on the earth and the ecological environment.
Biodegradable plastics are plastics that can be decomposed in specific environments and are usually made from biomass materials, starch, polylactic acid, etc. Biodegradable plastics can be broken down into smaller molecules and ultimately decomposed by microorganisms into natural compounds such as carbon dioxide and water, which will not cause permanent damage to the environment.
The principle of biodegradable plastics can be divided into three mechanisms: physical degradation, chemical degradation, and biological degradation:
Physical degradation: When biodegradable plastics are subjected to external forces such as mechanical, light, and temperature, the molecular chains are prone to break, and the plastic will be broken into small particles, ultimately forming environmental pollutants such as microplastics in the ocean.
Chemical degradation: Under the influence of chemical reactions such as oxidation, heating, and radiation, the bond structure in biodegradable plastics will break, causing the molecular chain to break and convert into small molecules such as water, carbon dioxide, and methane. Chemical degradation is usually faster than physical degradation.
Biological degradation: Some biologically active ingredients such as starch, polyhydroxy fatty acid esters are added to biodegradable plastics, making them able to be absorbed and decomposed by microorganisms, forming harmless substances such as water and carbon dioxide, thus achieving environmental friendliness.
It should be noted that although biodegradable plastics can decompose in their natural environment, this is only for natural conditions that meet regulations, such as temperature, humidity, acidity and alkalinity, etc. If the conditions are not met, biodegradable plastics can still cause environmental pollution. Therefore, it is crucial to use and handle biodegradable plastics reasonably.