Degradable materials are materials that can be degraded in the sense of thermodynamics and kinetics over a period of time. According to the external factors of degradation, it can be divided into photodegradable materials, biodegradable materials, etc. the main influencing factors are temperature, molecular weight, material structure, etc。
According to the external factors of degradation, it can be divided into:
1. Photodegradable materials: they are degraded by sunlight;
2. Biodegradable materials: they are degraded by the respiration or chemical energy synthesis of natural microorganisms such as fungi and bacteria, and finally decomposed into carbon dioxide and water;
3. Environmental degradation materials: degradation under natural environmental conditions such as light, heat, water, polluting compounds, microorganisms, insects and mechanical forces.
Recently mainly proudcts have : PLA,Starch Plastic
1,Polylactic acid (PLA)
Poly (lactic acid) (PLA), also known as poly (lactide), is chemically synthesized from lactic acid produced by microbial fermentation. It can be degraded automatically after use and will not pollute the environment.
PLA can be processed into fibers and films with excellent mechanical properties, and its strength is roughly equivalent to that of nylon fiber and polyester fiber. Polylactic acid can be decompose into lactic acid and acetic acid in organism, and metabolized into CO2 and H2O by enzyme, so it can be used as medical material. In Japan and the United States, PLA has been used to process surgical suture, artificial bone and artificial skin. Polylactic acid is also used in the production of packaging containers, agricultural film, fiber sportswear and bedding.
If the starch content is more than 90%, other components can be completely degraded. Sumitomo Corporation of Japan, wamer Lamber Corporation of the United States, ferrizz Corporation of Italy, etc. have declared that they have successfully researched all starch plastics with 90% - 100% starch content, which can be completely biodegraded without any trace in January to one year without pollution, and can be used to manufacture various containers, bottles, films and garbage bags And so on.
The production principle of all starch plastics is to make starch molecules deformed and disordered to form starch resin with thermoplastic properties, so it is also called thermoplastic starch plastics. The traditional plastic processing equipment can be used in the molding process.
The potential advantages of developing biodegradable plastics with starch as raw material are as follows: starch has complete biodegradability in all kinds of environments; after starch molecules in plastics are degraded or ashed, carbon dioxide gas will be formed, which will not cause toxicity to soil or air; appropriate technology will be adopted to make starch thermoplastic, which can achieve the mechanical properties used to make plastic materials; starch is recyclable The utilization of starch is beneficial to the development of rural economy.