The problem of marine plastic waste pollution has attracted global attention. How to reduce marine waste pollution has become a key research direction in various fields such as industry and scientific research institutions. A few days ago, the Chinese Academy of Sciences announced that it has successfully developed seawater degradable plastics and is expected to take the lead in Hainan.

Seawater degradable plastic products, the appearance is no different from ordinary plastic.

Cooperation with Hainan to promote industrialization

Earlier, the Department of Science and Technology of Hainan Province and the Institute of Physics and Chemistry Technology of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Physics and Chemistry of the Chinese Academy of Sciences) signed a strategic cooperation agreement in Haikou. The two parties will jointly build the Hainan Province Degradable Plastics Technology Innovation Center to study new technologies and new products in the field of degradable plastics. , New technology, etc., promote the pilot test of seawater degradable plastic technology in Hainan, in order to realize the industrialization of seawater degradable plastics as soon as possible.

Ji Junhui, a researcher at the Institute of Physics and Chemistry of the Chinese Academy of Sciences and director of the National Engineering Research Center for Engineering Plastics, said in an interview with the Hainan Daily: "Although seawater degradable plastics have been highly valued by global experts, international research on seawater degradable plastics is still rare, only China and Japan. Very few multinational companies and scientific research institutions in Germany, Germany and other countries have begun to study." Ji Junhui said.

In 2017, the National Engineering Research Center for Engineering Plastics and the Institute of Physics and Chemistry of the Chinese Academy of Sciences organized nearly 10 PhDs to study seawater degradable plastics. Starting from the molecular structure design, after difficult research and repeated experiments, in 2018, Ji Junhui team developed a polymer material that can be degraded in seawater, which can be understood as the "predecessor" of seawater degradable plastic products.

New plastics can degrade in seawater and land

Since 2018, Ji Junhui's team has conducted degradation tests and screening of seawater degradable polymer materials in different marine environments such as the Bohai Sea, the East China Sea and the South China Sea, and finalized the polymer material varieties with different application backgrounds. In the future, they can be based on different applications. Design materials with different properties.

"The sea trial was conducted to study the time for different polymer materials to maintain performance without significantly decreasing in different marine environments (that is, the possible service life of the product in the future), and the rate of degradation and disappearance, so as to judge the performance of plastics for development and application." Ji Junhui said that the current sea trial of seawater degradable plastics has achieved preliminary results in the preparation of seawater degradable plastics. The next step is to solve engineering and technical problems and prepare for industrial demonstration.

A comparison of the degradable plastic samples of seawater (upper) and well-preserved samples (lower) after soaking in seawater for 3 months.

"This new material is not only degradable in ocean water, but also degradable in soil, and can be decomposed into water and carbon dioxide and other substances in tens of days to hundreds of days after being discarded into the soil or ocean." Ji Junhui It said that although seawater degradable plastic was born, it is still at the laboratory level, and it has a long way to go before it is put into production.

The documentary "Plastic Ocean" exposes the disaster that plastic waste brings to the ocean. (Profile picture)

In addition to the development of marine degradable plastics by the Chinese Academy of Sciences, researchers at Cornell University (Cornell) have recently released a research progress: new plastics that are biodegradable under ultraviolet light for fishing applications.

●Extended reading: Plastic degradable under ultraviolet light●

About half of the marine plastic pollution comes from commercial fishing tools, such as fishing nets and fishing ropes. To this end, researchers at Cornell University (Cornell) have developed a new polymer for the fishing industry to reduce the plastic waste pollution caused by the fishing industry to the ocean.

Bryce Lipinski, a researcher at Professor Geoffrey Coates’ Implementation Room at Tisch University and the project’s principal investigator and PhD candidate in the Department of Chemistry and Chemical Biology at Cornell University, said that although scientists are trying to replace plastic with other materials, they are based on the plastic itself It’s not easy to replace it.

"The reality is that plastics will continue to exist, because in many applications, plastics can compete with other materials in terms of strength, flexibility, and weight. However, due to the extensive use of plastics and improper recycling, it leads to environmental pollution. "

Researchers at Cornell University tested a new marine durable polymer that can be biodegraded under ultraviolet light. (Source: Geoffrey Coates Laboratory, Cornell University)

The Cornell team decided to start with applications in specific fields, focusing on research and development of fishing tools that require easy access to the marine environment and require highly degradable functions. The most commonly used fishing nets and fishing ropes are mainly made of three polymers: isotactic polypropylene, high-density polyethylene and nylon 6,6. These three materials are not easily degraded.

Geoffrey Coates and his research team have been developing a plastic that can meet the needs of the fishing industry in terms of mechanical properties and can also degrade in a reasonable time over the past 15 years. The researchers developed a material called isotactic polypropylene oxide (iPPO), which was first discovered in 1949 and has a structure similar to isotactic polypropylene. Before the Cornell team studied this material, the mechanical strength and photodegradability of iPPO had never been discovered.

According to reports, iPPO is unique because of the large amount of symmetry and regularity in the polymer chain of the material, which can enhance the strength and degradability of the material. iPPO plastic is highly sensitive to ultraviolet degradation. The researchers found in laboratory tests that these materials had "significant photodegradation" within 30 days. However, the degradation rate depends on the light intensity.

Researchers hope that iPPO plastics can be used in commercial fishing applications such as fishing nets and fishing ropes to help reduce the amount of plastic pollution in the world's marine environment.

Reference: Hainan Daily, Institute of Physics and Chemistry, Chinese Academy of Sciences and DesignNews