PLA (common name: polylactide) has a glass transition temperature of about 38 ℃ and a crystallization melting point of 230 ℃ ~ 240 ℃. Its thermodynamic properties are similar to polystyrene and it is a hard plastic in glass state at room temperature. In addition, because PLA has an asymmetric carbon atom, the crystallization properties of PLA largely depend on the ratio of L-body and d-body (usually designed to have an L-body content of more than 98%). PLA is the only biodegradable plastic in practical application, which is also an important feature. The air permeability is higher than PE / PP, but the water vapor permeability (especially moisture permeability) is lower than polyolefins and pet, because it has higher water vapor permeability in glass state.
Polylactic acid (PLA) has good biodegradability. However, different from PCL and PBS, PLA is hydrolyzed first and then decomposed by microorganisms. Therefore, in the experiment, the processed products are decomposed smoothly in the soil and completely disappear after 1 ~ 2 years. In addition, according to ISO 14855, it can be decomposed rapidly in composting aerobic environment and in anaerobic environment.
PLA, PLA and PGA copolymer have been approved by FDA and can be used as scaffold, fixation, suture or loading materials in human medical clinic. Polylactic acid (PLA) will decompose into various harmless glucose and lactic acid after 12 months, and finally become CO2 and water in metabolism.
To sum up, the biodegradable bag produced with PLA as raw material can be called environmental protection packaging bag.
