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Dexuan Degradable Tableware-Degradable Materials In Seawater That “Disappear Automatically” After Use
- Aug 06, 2018 -

In the 19th century, plastic was born, which is known as one of the greatest inventions of mankind. But because white pollution is getting worse, plastic has become the "worst" invention. According to statistics, the annual global plastic waste is about 30 million tons, of which more than 8 million tons of plastic waste is directly discarded or passed through the river from the land, and the wind finally enters the ocean. The damage caused by plastic pollution to the marine environment far exceeds people's imagination. .

Degradable materials in seawater that “disappear automatically” after use

Recently, at the final of the first “First Cup” Future Technology Innovation Competition held in Shenzhen, the team of the National Engineering Research Center of Engineering Plastics of the Institute of Physics and Chemistry of the Chinese Academy of Sciences demonstrated a degradable material in seawater, which can effectively solve the problem of marine plastic pollution. The project is also one of the 30 projects that will eventually win the prize.

Color Degradable PLA Plastic Disposable Straw


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Inspired by biodegradable plastics

Where does plastic waste come from? A plastic bag with breakfast at the fast food restaurant on the way to work, a parcel bag sent by the little brother at noon, or plastic granules in the shower gel during bathing, etc. In many unexpected places, everyone will make many Plastic garbage.

In order to solve the problem of white pollution, the National Engineering Research Center of Engineering Plastics of the Institute of Physics and Chemistry of the Chinese Academy of Sciences has developed a kind of “biodegradable plastic”, which not only makes plastic products easy to use, but also “automatically disappears” after use.

Ji Junhui, director and researcher of the National Engineering Research Center of Engineering Plastics, Institute of Physics and Chemistry, Chinese Academy of Sciences, told the reporter of the Chinese Journal of Science and Technology: "Biodegradable plastics are mostly polymer materials with ester bonds, and the molecular chains are relatively 'fragile', so they can be decomposed by many microorganisms in nature. Digest, eventually forming carbon dioxide and water that are harmless to the environment.

Currently, commercially available biodegradable plastics include polylactic acid (PLA), polybutylene succinate (PBS) and copolyesters (PBAT), polycaprolactone (PCL), and polyhydroxyalkanoates. (PHA), etc. These materials have become recognized, green and fully biodegradable materials. They have gradually replaced polypropylene (PP), polyethylene (PE) and other non-degradable and non-degradable plastic products in many fields such as disposable packaging, mulch film and disposable tableware. .

While solving the problem of white pollution on land, the increasingly serious pollution of marine plastics has attracted the attention of Ji Junhui. “Since 2016, the global coverage of marine plastic pollution has been overwhelming. Because we have a lot of experience in research and development of biodegradable plastics in the early stage, we immediately developed the idea of developing seawater degradable materials. From the material point of view, there was no experience at home and abroad. Can learn from, but because we are doing degradable plastics, we feel that this matter is obligated to complete." Ji Junhui said.

Biodegradable Compartment Plastic Food Plate


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Technological innovation to achieve marine degradation

After determining the direction of the development of seawater degradable materials, Wang Gexia, a senior engineer at the Institute of Physics and Chemistry of the Chinese Academy of Sciences, conducted a systematic research work. Through multiple trials, they found that materials with good biodegradability in soil and compost did not degrade in seawater.

Wang Gexia said: "We thought this was an easy task. We could adapt the biodegradable material to the marine environment, but the reality was a cold water."

This is how it happened? After careful study, Wang Gexia found the answer. “The composting process of polyester material is an enzymatic hydrolysis reaction under the action of microorganisms; while the seawater temperature is low, the specific microbial species are few, the quantity is small, and it is difficult to have biodegradation conditions, so most polyester materials have a very long degradation cycle in seawater. Slow, even difficult to degrade."

Degradable materials in seawater that “disappear automatically” after use

Wang Gexia said that different regions of seawater have great differences in different periods. It is hoped that the materials can be completely degraded in a controlled cycle. It is impossible to rely solely on the biodegradation process. The problem we face is to solve the problem of refractory and non-degradable water in existing materials, and to meet certain application performance and environmental adaptability according to different application requirements.

After repeated experiments, Wang Gexia and team members successfully came out of this dilemma. Starting from molecular design and two-phase synthesis, they introduced non-enzymatically hydrolyzed groups into biodegradable polyester systems through polymer synthesis modification and blend modification to achieve overall controllable degradation of materials in seawater. .

“Now we can develop seawater degradable materials that can disintegrate or degrade in different cycles from several minutes to several hundred days. Its degradation cycle and degradation mode can be adjusted according to different application requirements. In the future, we hope that this material will degrade. Can be intelligent." Wang Gexia said.