Degradable plastics refer to a class of plastics whose products have various properties that can meet the requirements of use, remain unchanged during the storage period, and can be degraded into environmentally sound substances under natural environmental conditions after use. Therefore, it is also called environmentally degradable plastic.
The degradation time of degradable plastics under normal climate and soil conditions is 3-6 months, while the degradation time of traditional degradable plastics takes decades to hundreds of years.
Classification of degradable plastics
According to the degradation mechanism, it is divided into: Photo-degradable plastic, biodegradable plastic and photo-biodegradable plastic.
Photo-degradable plastics: The development started and matured earlier, but due to application limitations, production began to decrease gradually in the 1990s;
Biodegradable plastics: It has entered the stage of industrial production from the research and development stage, and global demand and production capacity have steadily increased. If the cost can be greatly reduced, it will usher in an outbreak period;
Photo-biodegradable plastic: Combining the advantages of the first two, it is the future development direction of degradable plastics, but it is still in the laboratory stage.
Among them, biodegradable plastics can be divided into bio-based degradable plastics and petroleum-based degradable plastics according to raw materials.
Biodegradable plastics: starch mixture, PLA and PHA;
Petroleum-based biodegradable plastics: PCL, PBS, PBAT, PPC, PGA.
The mainstream in the future is fully degradable plastic PLA and PBAT.
PLA and PBAT are typical completely degradable plastics. Plastics have almost no shortcomings in impact resistance, stretch and elasticity, and the domestic technology is relatively mature. They are currently the most promising degradable plastics.
PLA: Superior performance. PLA has technical barriers to lactide. The mainstream high-molecular-weight PLA production process is lactide ring-opening polymerization. However, there is a big gap between my country’s lactide technology and foreign countries, and there are technical barriers.
PBAT: The most potential for growth, there is little gap between domestic technology and foreign countries. The capacity utilization rate is already at a high level, and the cost is 1.26 times that of ordinary PE, and it has the conditions to enter the rapid expansion cycle.