New marine-biodegradable polymer decomposes by 92% in one year, rivals nylon in strength

(Press-News.org) Nylon-based products such as clothing and fishing nets are notoriously slow to degrade, especially in marine environments, contributing significantly to global ocean pollution. A Korean research team has now developed an innovative material that can be produced using existing manufacturing infrastructure and effectively addresses this problem.

A joint research team led by Dr. Hyun-Yeol Jeon and Dr. Hyo-Jeong Kim at the Korea Research Institute of Chemical Technology (KRICT), Senior Researcher Sung-Bae Park, Professor Dong-Yeop Oh at Inha University, and Professor Je-Young Park at Sogang University has developed a high-performance polyester-amide (PEA) polymer that decomposes by over 92% in one year under real marine conditions, while maintaining strength and flexibility comparable to nylon. This material is not only scalable and recyclable but also applicable to a wide range of uses such as textiles, fishing nets, and food packaging.

Unlike conventional biodegradable plastics that suffer from low durability and heat resistance, the PEA polymer combines ester (for biodegradability) and amide (for toughness) linkages in an optimal ratio. This design offers both high degradability and mechanical durability.

Traditionally, the synthesis of polymers with both ester and amide groups required toxic organic solvents. However, the team developed a new two-step melt polymerization process that eliminates the need for solvents and enables industrial-scale production (up to 4 kg) in a 10-liter reactor. Importantly, this method is compatible with existing polyester manufacturing facilities with only minor modifications, enhancing its industrial scalability.

Marine biodegradability tests conducted off the coast of Pohang showed that the new PEA achieved up to 92.1% degradation within one year—significantly outperforming existing biodegradable plastics such as PLA (0.1%), PBS (35.9%), and PBAT (21.1%). Even more complete biodegradation occurs under composting conditions, where microbial populations are higher.

The tensile strength of the PEA reached up to 110 MPa, surpassing that of nylon 6 and PET. In practical experiments, a single PEA fiber strand was able to lift a 10 kg object without breaking. When woven into fabrics, it also withstood ironing at 150°C, confirming its high thermal resistance.

In addition to performance, sustainability was a key focus of the research. The PEA was synthesized using long-chain dicarboxylic acids derived from castor oil (a non-edible crop), and caprolactam derivatives recovered from recycled nylon 6 waste. This upcycling approach reduced CO₂ emissions to just one-third that of conventional nylon 6—lowering emissions from 8–11 kg CO₂eq/kg to 2.3–2.6 kg CO₂eq/kg.

The team is currently evaluating the material for commercialization, with expectations for industrial adoption within two years.

Dr. Sungbae Park stated, “The key achievement is that this material overcomes the limitations of conventional biodegradable plastics while offering nylon-level performance.” KRICT President Young-Kuk Lee added, “This technology marks a pivotal step toward the commercialization of biodegradable engineering plastics and will significantly contribute to solving the global marine plastic pollution crisis.”

This research was published as a cover article in the March 2025 issue of Advanced Materials (IF: 27.4). Dr. Sungbae Park and postdoctoral researcher Hojung Kwak are co-first authors, and Drs. Jeon and Kim (KRICT), Prof. Oh (Inha University), and Prof. Park (Sogang University) are corresponding authors.

 

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KRICT is a non-profit research institute funded by the Korean government. Since its foundation in 1976, KRICT has played a leading role in advancing national chemical technologies in the fields of chemistry, material science, environmental science, and chemical engineering. Now, KRICT is moving forward to become a globally leading research institute tackling the most challenging issues in the field of Chemistry and Engineering and will continue to fulfill its role in developing chemical technologies that benefit the entire world and contribute to maintaining a healthy planet. More detailed information on KRICT can be found at https://www.krict.re.kr/eng/

The study was conducted with support from KRICT’s basic research fund and the Ministry of Trade, Industry and Energy, and the Ministry of Agriculture, Food and Rural Affairs.

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