How Does the Biodegradable Plastic Garbage Bag Decompose?

Ⅰ. Introduction of biodegradable plastic trash bags

Biodegradable plastic garbage bags refer to adding a certain amount of additives (such as starch, modified starch or other cellulose, photosensitizers, degradants, etc.) during the production process to reduce their stability and make them easier to leave in the natural environment. Plastic garbage bags are degraded in the background. Biodegradable plastic garbage bags are made of plant straws and other raw materials. Unlike other synthetic plastics, biodegradable plastic garbage bags can be decomposed by themselves under the action of the biological environment after they are discarded. There is no harm to the environment, and it is a green product.

Ⅱ. Decomposition conditions of biodegradable plastic trash bags

PLA (polylactic acid), the main ingredient in biodegradable plastic garbage bags, does not decompose quickly, especially during use. The beginning of the biodegradation process requires a high temperature, high humidity environment and microbial nutrient sources. The decomposition of  biodegradable plastic trash bags is inseparable from the specific conditions of temperature and humidity. At room temperature (25°C), the hydrolysis process starts half a year later, and it takes nearly a year for the biological decomposition to start. In the initial decay, microorganisms have little effect, an essential feature of degradable plastic bags.

Under composting conditions, decomposition will proceed quickly with high temperature (60~70℃) and high humidity (50%~60%) conditions. The eco biodegradable bags first begin to hydrolyze under the composting condition at 60°C. The average molecular weight of biodegradable plastic garbage bags is 10,000. When the molecular weight becomes 20,000, it becomes brittle, and when the molecular weight becomes 10,000, it becomes crushed. At this time, the biological decomposition begins, PLA (polylactic acid) is decomposed into lactic acid and lactic acid oligomers, and carbon dioxide is released. The decomposition mechanism of these two stages is characteristic of degradable garbage bags. 

Therefore, if you want to degrade all PLA garbage bags safely and without pollution, the best treatment method is to compost.