Researchers led by Professor Takuzo Aida of the Center for Advanced Materials Science (CEMS) at the RIKEN Research Institute in Saitama, Japan, have developed a durable plastic that does not contribute to microplastic pollution in the ocean. 

The new material is as strong and biodegradable as traditional plastics, but what makes it special is that it breaks down in seawater. As a result, the new plastic is expected to help reduce harmful microplastic pollution that accumulates in the oceans and soil and eventually enters the food chain. The results of the experiment were published Nov. 22 in the journal Science.

Scientists have been working to develop safe and sustainable materials to replace traditional plastics, which are unsustainable and harmful to the environment. While some recyclable and biodegradable plastics already exist, a major problem remains.

Currently biodegradable plastics like polylactic acid (PLA) often find their way into the oceans, where they cannot degrade because they are insoluble in water. As a result, microplastics (pieces of plastic smaller than 5 millimeters) are harming aquatic life and entering the food chain, including our bodies. 

In their new study, Aida and her team addressed this problem using supramolecular plastics, which are polymers that link structures together through reversible interactions. The new plastic is made by combining two ionic monomers that form cross-linked salt bridges, which give the material its strength and flexibility. In preliminary tests, one of the monomers was sodium hexametaphosphate, a common food additive, and the other was a monomer of several guanidinium salt cations. Both monomers are metabolized by bacteria, ensuring that the plastic is biodegradable when broken down into its constituent parts. 

Key Breakthrough: Salt Bridge Structures and Controlled Degradation

Aida said, “It has long been assumed that the reversibility of chemical bonds in supramolecular plastics would make them fragile and unstable, but the new material we have developed is just the opposite.” In this new material, the salt-bridge structure is irreversible unless exposed to an electrolyte environment like that contained in seawater. The key discovery lies in how to make these selectively irreversible cross-linked structures. 

As with oil and water, the researchers mixed the two monomers in water and observed the appearance of two separate liquids. One liquid was thick and viscous and contained cross-linked salt bridges that form important structures, while the other was watery and contained salt ions. For example, when sodium hexametaphosphate and alkyl diguanide sulfates are used, the sodium sulfate salt is drained into the aqueous layer. The final plastic, alkyl SP, is made by drying the remaining material from the thick viscous liquid layer. 

The “desalination” step proved to be critical; without it, the final dried material would be a fragile crystal that could not be used. By re-salting the plastic in brine, the cross-linked structure is rapidly deconstructed and completely disintegrated within a few hours. Thus, having created a plastic that is strong and durable and still dissolves under certain conditions, the researchers next tested the qualities of the plastic. 

Key discovery: reshaping supramolecular polymers

The new plastic is non-toxic and non-flammable - meaning no carbon dioxide emissions - and can be reshaped at temperatures above 120°C like other thermoplastics. By testing different types of guanidinium sulfate, the team was able to create plastics with varying hardness and tensile strength, properties that are comparable to or even better than traditional plastics. This means that this new type of plastic can be customized on demand; hard, abrasion-resistant plastics, rubbery silicone-like plastics, plastics with high load-bearing capacity, or low-tensile flexible plastics are all possible. The researchers have also created ocean-degradable plastics using polysaccharides that can form cross-linked salt bridges with guanidine monomers. Such plastics could be used for 3D printing as well as medical or health-related applications.

A new family of plastics: recycling and the environment at the same time

Finally, the researchers investigated the recyclability and biodegradability of the new plastic. After initially dissolving the new plastic in salt water, they were able to recover 91% of the sodium hexametaphosphate and 82% of the guanidine in powder form, suggesting that the recycling process is easy and efficient. In soil, the new plastic flakes degraded completely in 10 days, acting as a fertilizer to provide phosphorus and nitrogen to the soil. 

Says Aida, “With this new material, we have created a new family of plastics that are strong, stable, recyclable, multifunctional and, importantly, do not produce microplastics.”

Polylactic acid (PLA), as a typical polymer material derived from renewable raw materials (starch), is gradually developing into a basic bulk material necessary for society. At the same time, the post-processing of used PLA materials has attracted attention. Although PLA can be degraded in nature, the process usually requires a long time and specific degradation conditions, and the degradation products are carbon dioxide and water, which cannot be directly and rapidly recycled, and is essentially a carbon emission process and a waste of resources. The recycling of PLA by means of chemical recycling provides an effective solution for the reprocessing of waste PLA. Most of the current research is to convert waste PLA to alkyl lactate, but cycling through this process to obtain high molecular weight PLA materials requires hydrolysis of alkyl lactate into lactic acid, prepolymerization into oligomers, dimerization into propyl cross esters and then polymerization to obtain PLA, which are feasible but costly and inefficient (shown in Figure 1). Therefore, realizing the direct conversion of waste PLA materials into new PLA materials has important research value and application prospects.

Figure 1 Polylactic acid cycling strategy

The Catalytic Polymerization and Engineering Research Group led by Qinggang Wang at the Qingdao Institute of Energy, China, has developed a new upcycling strategy of polymer degradation and re-polymerization (“DE-RE polymerization” strategy) to successfully realize the recycling process from PLA waste to new PLA materials in a “polymer-to-polymer” manner (shown in Fig. 2). A new upcycling strategy (“DE-RE polymerization” strategy) has been developed by the Catalytic Polymerization and Engineering Research Group, led by a researcher from the Catalytic Polymerization and Engineering Research Group. 

The mild reaction conditions and few side reactions of this strategy reduce the consumption of raw materials for the complete reproduction of PLA and maximize the recycling efficiency of PLA. During the re-polymerization process, final materials with different properties can be obtained by adding different types of monomers. The results provide a new solution idea for the recycling of PLA and promote the development of a sustainable society. 

In addition, this strategy is not only effective in chemical recycling, but also promising in polymer modification and synthesis. 

Fig. 2 Chemical recycling of PLA waste plastics

On November 29, Professor Deng Hongbing's team from Wuhan University's School of Resource and Environmental Sciences and Professor Zhou Xue's team from Huazhong University of Science and Technology (HUST) joined hands to make an important breakthrough in scientific research, successfully developing a new type of all-biomass fiber sponge that is reusable and biodegradable. The relevant research results have been published in the international academic journal “Science Advances”.

Figure 1, Sustainable self-assembled supramolecular biomass fiber foam for microplastic removal. (A) Pathway for the preparation of self-assembled supramolecular biomass foams without cross-linking of cellulose and β-chitin. (B) Due to the abundance of reactive functional groups, the biomass fiber foam removes microplastics through multilevel interactions (physical interception, electrostatic adsorption, and multiple intermolecular interactions). 

Wuyang Wu, Postdoctoral Fellow, School of Resource and Environmental Sciences, Wuhan University: Our research found that the crystalline form of chitin from squid bone is different from that of lobster shell chitin, which has higher reactivity and is easier to be made into sponges that can adsorb more microplastics. China's huge squid catch, a large number of squid bone as waste can be used as raw material for chitin extraction, making more efficient all-biological microplastic adsorption sponge. 

The sponge, made from chitin extracted from discarded squid bones and cotton, has a porous structure and rich surface functional groups that excel in treating microplastic contamination in water. The research team evaluated the material's performance using samples from four actual water sources: irrigation water, lake water, seawater, and pond water, and found that the material's adsorption capacity was largely unaffected by inorganic particles, heavy metals, organic pollutants, and microorganisms in the water, determining its stability in real-world waters. The study showed that this new all-biomass fiber sponge removed 99.8% of microplastics from water in the first adsorption cycle and maintained over 95% removal after five cycles, demonstrating its good reusability.

Microplastic pollution has become a global environmental challenge, posing a serious threat to aquatic ecosystems and human health. The emergence of this new all-biomass fiber sponge is undoubtedly a highlight in the field of environmentally friendly materials. 

It is worth mentioning that the sponge not only has excellent adsorption performance, but also has the characteristics of reusable and biodegradable. After adsorption saturation, the sponge can be easily desorbed and regenerated through a specific treatment process, and can be recycled many times, greatly reducing treatment costs and resource consumption. When the sponge reaches the limit of its service life, it can be gradually biodegraded in the natural environment, not like the traditional adsorbent material that leaves secondary pollution hidden danger, truly realizing the environmental friendliness of the whole process from use to disposal. 

Prof. Deng Hongbing said that biomass materials are an effective and economical solution to the complex problem of microplastic pollution in water, and that this all-biomass fiber sponge is simple to prepare, has the potential for large-scale production, and is expected to be applied to real-life large-scale water treatment or within household water purifiers in the near future. Prof. Zhou Xue also mentioned that inter-university teamwork played a key role in this research, as experts and researchers from different disciplinary backgrounds collaborated with each other and complemented each other's strengths to make this comprehensive and technically challenging research go forward smoothly.

Recently, Italian company Mixcycling has successfully developed bio-based materials for packaging and closure in the food industry based on PLA, PHBH and cork as natural fillers. 

First, the choice of this material is strategic because both PLA and PHBH are biodegradable, derived from renewable resources and decompose efficiently under a variety of environmental conditions. The biodegradable nature of these materials allows for organic recycling, enabling waste to be converted into valuable compost and reducing its environmental impact.

Secondly, this material shows excellent mechanical properties, and the addition of cork improves its flexibility, strength and durability, in line with the performance requirements of traditional bottle caps, resistant to the stresses common to everyday use. These properties maintain the quality of the products they seal, such as olive oil.

Mixcycling, a member of the European Green Cycle Coalition, supplied the material to the Italian company Le Terre di Zoé for the production of extra virgin olive oil (EVO) caps. 

Mixcycling has also partnered with Guala Bottle Caps to produce biocomposites that have been used in tamper-resistant bottle caps that are comparable to those produced from traditional plastics in terms of strength, hygiene and versatility of use. Prototypes of screw caps and olive oil dispensers have been made by injection molding.

Mixcycling researchers have also developed a microwave-assisted molding process that promises to reduce energy consumption by 30 percent and improve material properties. 

The Green Cycle project, co-funded by the European Union under the European Horizon program, aims to revolutionize the production of bio-based materials through the development of sustainable manufacturing technologies. A key objective is to replace traditional fossil-based plastics with biodegradable and compostable alternatives. 

Mixcycling was founded by brothers Gianni and Amerigo Tagliapietra in 2020 and has won international awards and recognition as an industry player in 2023.Mixcycling's technology is based on a patented process and know-how that values organic waste and mixes it with bio-based and fossil-based materials for EssilorLuxottica, Stoelzle Glass Group, SCHID Spa, UniCredit StartLab, Adamo srl, Lavazza Group, Stilfibra srl, DeRoma Group, Selle Royal Group Spa and other Major industrial groups create new raw materials. 

Guala Caps is a global leader in bottle caps for the spirits, wine, beverage, oils and flavors markets. The Group has 35 production plants around the world to ensure proximity to its customers and to provide tailor-made services and solutions.

In recent years, growing concerns about plastic pollution and its harmful effects on the environment have prompted researchers and innovators to seek sustainable alternatives. This push for environmentally friendly solutions has led to the development of various degradation technologies designed to enhance the breakdown of plastics in a more environmentally friendly manner. Notably, four major advances in this area include AUTAC degradation technology development, LYTAC degradation science and technology development, AbTAC degradation process development and ATTEC degradation technology development. Each of these technologies offers a unique approach to addressing the global plastic waste crisis.

AUTAC degradation technology development

AUTAC (Autonomous Catalytic Degradation) degradation technology focuses on the autonomous decomposition of polyolefins, one of the most commonly used plastics today. The technology utilizes catalysts to promote degradation without the need for external intervention. By embedding these catalytic materials in a plastic matrix, AUTAC enables plastics to break down into environmentally sound products under natural conditions. This technology has the potential to significantly reduce the lifespan of plastic waste in the environment and contribute to a circular economic model.

LYTAC degradation technology development

The core of LYTAC (Lysosomal Targeting and Catalysis) degradation technology is the use of lysosomal targeting to degrade biobased and synthetic polymers. This technology utilizes natural biological processes to facilitate the breakdown of plastics into harmless biomolecules that can be absorbed by living organisms.The LYTAC technology demonstrates a multidisciplinary approach that combines biochemistry and materials science to enhance the biodegradability of plastics while maintaining their functionality over their expected life cycle. The impact of this technology could be transformative, especially in medical applications where plastics are often disposed of in ways that lead to contamination.

AbTAC degradation technology development

AbTAC (enriched catalytic) degradation technology represents a disruptive advancement in the field of polyesters and polyamides. The technology utilizes common natural catalysts, such as enzymes and microorganisms, to accelerate the degradation process. The AbTAC approach prioritizes the use of abundant and readily available resources, making it cost-effective and scalable for large-scale production. This approach not only reduces the burden on the environment, but also ensures that plastics can be effectively recycled or reused after their useful life. By utilizing nature's toolkit, AbTAC promises to make plastic waste management a more sustainable process.

Development of ATTEC degradation technology

ATTEC (Advanced Thermochemical and Enzyme Catalyzed) degradation technology embodies an innovative hybrid approach that combines thermochemical processes with enzymatic reactions to efficiently break down complex polymers. This approach allows for the selective breakdown of specific plastic types and the recovery of valuable monomers, thus creating the potential for closed-loop recycling systems. ATTEC's versatility makes it suitable for a wide range of plastic materials, effectively addressing the diverse composition of plastic waste in the modern world. Furthermore, this technology demonstrates how interdisciplinary collaboration can lead to breakthroughs that significantly reduce environmental impact.

reach a verdict

Advances in the development of AUTAC, LYTAC, AbTAC and ATTEC degradation technologies represent beacons of hope in the search for sustainable solutions to plastic pollution. As these technologies continue to evolve and become more commercially viable, they have the potential to transform the way we make, use and dispose of plastics. Through collaborative efforts in research and development, these innovative approaches not only promise to reduce the environmental impact of plastic waste, but also pave the way for a more sustainable future. Achieving a balance between convenience and environmental stewardship is critical, and with these degradation technologies, we are one step closer to a circular economy that prioritizes ecological integrity.

Founded in 2019, Shellworks (Shellworks) is a London-based company that grew out of a team project set up jointly by the Royal College of Art and Imperial College to develop an eco-friendly plastic bag that is biodegradable. It is hoped that this will replace the commonly used single-use plastic bags and reduce the pressure of waste products on the environment. 

Later in the company's commercial operations, however, a blend of chitosan with starch and low-grade fibers was used to produce rigid packaging for cosmetics.

Research shows that almost all crustaceans have a component called “chitosan”. Lobster shells have the highest content of 30% to 40%, the biggest characteristic of this ingredient is non-toxic, easy to degrade.

To make biodegradable plastic bags from crayfish, you can follow these steps:

1. Preparation materials: crayfish shells, corn starch, plasticizer, chitosan solution, hydrogen peroxide, sodium hydroxide (for decolorization and deacetylation)

2. Dispose of crayfish shells: Clean the crawfish shells and remove the meat, reserving the heads, pincers and legs.

Rinse the crayfish shells repeatedly with hot water to remove the oil film. 

Use baking soda to clean the crawfish shells and then slow bake them on low for 10 hours to make them clean and crispy. 

Powder the crayfish shells.

3. Make chitosan: Add the crayfish shell powder to the sodium hydroxide solution and stir until the calcium carbonate is dissolved.

A low concentration of sodium hydroxide solution was used to remove proteins from crayfish shells.

Use hydrogen peroxide to decolorize.

Chitosan was made by adding sodium hydroxide solution to deacetylate chitin in crayfish shells to 85%.

4. Making bio-based plastic bags:

Combine corn starch, plasticizer and chitosan solution and mix well.

Spray the mixture onto the mold using a spray gun or brush and then dry.

A starch-based chitosan bioplastic film can be obtained.

5. Testing and optimization:

The produced plastic bags were tested for their light transmission, flexibility, tensile strength and natural degradation time.

Optimization based on test results to improve the performance of plastic bags.

With the above steps, a biodegradable bio-based plastic bag can be made using crayfish shells.

Starting in November 2024, the global beverage industry giant, Japan's Suntory Group (SUNTORY), launched PET bottles produced using paraxylene (Bio-Paraxylene), which is extracted from waste cooking oil. This will be the world's first commercially available bioparaxylene PET bottle and will help to significantly reduce CO2 emissions compared to PET bottles made from traditional petroleum-based feedstocks. Suntory Group plans to produce approximately 45 million PET beverage bottles and further expand their use. PET resin, the raw material for PET bottles, is made up of 30% ethylene glycol (MEG) and ‍70% terephthalic acid (TPA)‍. Since 2013, the Suntory Group has been using plant-sourced MEG in its PET bottles for its Natural Water brand.In this new challenge, the Group has succeeded in producing TPA on a commercial scale from waste cooking oil.

Back in September 2023, Suntory Holdings announced a partnership with ENEOS to collect waste cooking oil from Japan. Suntory Group is also considering utilizing this collaboration to produce bio-based PET bottles using bio-naphtha from ENEOS' sustainable aviation fuel plant, which is scheduled to begin operations after 2027. According to the Suntory Group Plastics Policy developed in 2019, the group plans to use only recycled or bio-based materials for all PET bottles globally by 2030 and eliminate the use of petroleum-based materials. To achieve this goal, the Group has been working for some 20 years to reduce the weight of PET bottles, caps and labels through its 2R+B (Reduce/Recycle + Bio) strategy. The Suntory Group is also actively promoting horizontal “bottle-to-bottle” recycling in Japan through agreements with more than 100 municipalities and 40 companies, and is introducing recycled PET bottles in its products. By 2023, more than half of the soft drink bottles sold by Suntory in Japan will use 100% recycled PET bottles. Through a number of initiatives, the Suntory Group will continue its efforts to realize a circular economy and a carbon-neutral society.

OXMAN, a U.S.-based design lab, recently launched O° (pronounced “O-Zero”), a biomaterials, digital and robotics platform. The lab's first product made using the O° platform is a line of shoes made entirely of polyhydroxy fatty acid esters (PHA).

Computationally Designed, 3D Printed PHA Shoes from OXMAN Labs

The O° platform is used to produce bio-based textiles and wearables that are 100% biodegradable, contain no petrochemicals or glues, and produce no microplastics. In the actual production process, the O° robotic system 3D prints a customized PHA blend onto a textile, which is then 3D knitted with 100% PHA yarn produced through extrusion and melt spinning processes.

Three students in Turkey have created a company that produces plastics from recycled olive kernels and are exhibiting their products at the FAKUMA plastics fair (Oct. 15-19) in Germany. The company is called Biolive Biyolojik ve kimyasal teknolojiler san tic a.s. and is based in Istanbul, Turkey. 

Ahmet Ayas

Ahmet Ayas, who is the company's co-founder and sales manager, hatched the idea of recycling olive kernels to make bioplastics that can be used in a variety of products during an entrepreneurship class at Istanbul Technical University in 2017, which eventually evolved to a lab scale and then a pilot program that became a commercial operation about 18 months ago.

The company's current capacity is around 800 tons of olive pits per month. ayas says that current production is around 250 tons, so there is room for the company to grow the plant. biolive is not worried about the source of the raw material, as turkey is one of the largest olive producers in the world, with 500,000 tons of pits being produced every year in turkey alone. Globally, this figure jumps to 6 million tons, and Biolive has already established relationships with olive processors, where the pits were originally burned or landfilled.

Ayas said that olive pits are placed inside a reactor at pressure and temperature to be converted into a material that can then be used to make bioplastics, which can then be used on their own or in combination with other traditional plastics, such as polypropylene, for greater sustainability. 

Ayas was reluctant to discuss the details of the company's process, fearing that such information could spark competition. He said, “It's mostly cellulose-based materials, not cellulose, because these materials are very well suited to other plastics.” According to the company's website, one of the products, called “Bio Pura,” is a 100 percent bio-based and biodegradable biopolymer derived from olive pits. 

Today, Biolive's products are predominantly produced by injection molding methods, usually with polypropylene, but they are also being used with other resins such as ABS and polyethylene.Biolive is also currently working to introduce its products into other applications, including polycarbonate and combinations of polycarbonate and ABS.

In addition to creating a sustainability story by reusing olive kernels in place of petroleum-based plastics, Biolive notes that energy savings can be realized by introducing its materials. This is due to the fact that processing temperatures are likely to be around 25-30 degrees lower than typical. This reduces the carbon footprint of production.

Ayas says, “We offer the same production, the same machinery, the same molds and almost the same parameters, only with lower production temperatures. The rest is the same.” He counts both Emin Oz and Duygu Yilmaz as co-founders. The company has attracted 20 investors since its inception.

Ayas says there is a slight price premium for using Biolive compared to using only traditional resins.