What is degradable plastic?

What is degradable plastic?

Degradable plastics refer to plastics that can be completely degraded into environmentally harmless substances such as carbon dioxide, methane, water, and mineralized inorganic salts under certain circumstances or in the natural environment. As a new type of polymer material, degradable plastics include many types, and technical routes are also under continuous development.

From the perspective of raw materials, degradable plastics can be derived from petrochemical raw materials or biomass materials. From the perspective of degradation mechanism, degradable plastics include biodegradation, photodegradation, and oxidative degradation. From the perspective of degradation effect, it can be divided into full degradation and partial degradation.

Which degradable plastic can be used by consumers?

Choose plastics that are fully degradable and the degradation products are not harmful to the environment. At present, fully biodegradable plastics are mainly used in the market with more mature technical routes, better industrial chain foundation, and more complete standard testing systems.

Traditional plastics and starch can form starch-based plastics, and calcium carbonate can form "stone paper", which cannot be fully degraded. However, it is difficult to prove that oxidative degradation and photodegradation plastics will degrade into small molecules that are harmless to the environment. In the marine pollution prevention and control bill issued by the European Union in October 2019, the addition of degradable plastics and photodegradable plastics that cannot be fully degraded have been banned from 2021.

Total biodegradation = 100% degradation?

It's not. In terms of degradation ratio, according to relevant testing methods, the biodegradation rate of biodegradable plastics should reach more than 90%. A biodegradation rate of more than 90% is considered to be full degradation, because when degradation occurs in compost, soil and other environmental conditions, a small part (less than 10%) of the organic carbon contained in biodegradable plastic becomes biological dead body or mineralization Inorganic salt.

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Can fully biodegradable plastics only be degraded under composting conditions?

Composting is just one of the scenarios where biodegradable plastics are degraded. Most biodegradable plastics will be degraded in natural environments such as soil, fresh water or seawater under suitable temperature and humidity conditions, and will eventually be completely decomposed into environmentally sound substances by microorganisms.

Materials such as PBAT, PCL, PHA, etc., can be completely degraded within 6 months at the fastest when the soil, sea water and other conditions are suitable. PLA materials can also be degraded in natural environments such as soil and seawater.

Will the fully biodegradable plastic be degraded during use?

Will not. The degradation conditions of degradable plastics include light, oxygen, heat, water, biology and microorganisms and many other factors, especially microorganisms are indispensable. In daily use, these factors will not be present at the same time, so it will not be degraded.

Degradable plastic = bio-based plastic?

The two cannot be equal. Degradable plastics are more from the perspective of environmental pollution control, considering whether materials or products can be completely degraded after being discarded and entering the garbage disposal system or leaking into the environment, and it is harmless to the environment or does not cause pollution to the environment. . Bio-based plastics are more from the perspective of material raw materials, using renewable resources such as biomass to manufacture materials or products to save the use of fossil resources.

In general, degradable plastics are not necessarily bio-based, they may be bio-based or non-bio-based; bio-based plastics are not necessarily degradable, they may be degradable or non-bio-based. Degradable.