Tag: Recycle

Safer, Greener LDPE Alternatives Unveiled

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Low-density polyethylene (LDPE) is a soft, flexible plastic widely used in applications such as plastic films, bottles, and other pliable products.

A new sustainable method replicates the desirable properties of LDPE plastic using less energy, through a novel catalytic process that creates a ladder-like molecular structure, making it industrially viable.

Researchers have developed a more sustainable method to do the work required to make plastics that are comparable to widely used low-density polyethylene (LDPE) plastics. They say their method is industrially viable. LDPE is a soft, flexible, and lightweight plastic material that is widely used in a variety of commercial applications, including plastic films, bottles, and other pliable products.

LDPE’s unique properties are derived from its tree-branch-like molecular structure, bestowing flexibility. The material is also ductile due to its lower crystallinity. These properties set it apart from other, more linear varieties of polyethylene. However, the characteristic long-chain branching polymerization of LDPE is achieved through an energy-intensive, high-pressure synthesis process.

Here, Robert Froese and colleagues describe a novel approach to control long-chain branching in polyethylene under milder, solution-phase conditions. The method uses dual-chain catalysts, which can assemble two polymer chains at once, linked to one another through a small amount of diene mixed in with the ethylene, creating a ladder-like molecular structure. According to Froese et al., the ladder-branching process produces a plastic that exhibits comparable properties to those of LDPE or its blends with other forms of linear low-density polyethylene (LLDPE).

Reference: “A commercially viable solution process to control long-chain branching in polyethylene” by Robert D. Froese, Daniel J. Arriola, Jaap den Doelder, Jianbo Hou, Teresita Kashyap, Keran Lu, Luca Martinetti and Bryan D. Stubbert, 14 March 2024, Science.
DOI: 10.1126/science.adn3067

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April 23, 2024
23 Everyday Products Made of Recycled Materials (2024): Chargers, Watches, Toys

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Humans haven’t been kind to the planet. Climate change is out of control, microplastics are poisoning our oceans, and landfills are overflowing with trash. No matter how much we try to reduce our footprint, we still occasionally need new things. Luckily, some companies have figured out how to reuse waste to make new products from old plastic, textiles, and other materials that would otherwise fill our landfills and oceans. We’ve highlighted our favorites here.

It’s not a perfect sustainability solution, but if you already need a new portable charger or yoga mat, for example, you can buy one of these items knowing that it’s a little better than the alternative. Check out our other eco-friendly guides, like the Best Recycled Bags, Best Recycled Clothing, Best Eco-Friendly Cleaning Supplies, and Best Reusable Products.

Updated April 2024: We’ve added the new Nimble Champ portable charger, Humanscale’s Path chair, Bearaby’s Ocean Hugger weighted blanket, Revival’s denim rug, House of Marley’s Redemption 2 ANC headphones, Keiko Furoshiki gift wrap, and the new recycled MakeUp Eraser.

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April 22, 2024
New Polymers Made From Plant Cellulose

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Scientists have devised a way to produce recyclable and stable polymers from cellulose, offering a sustainable alternative to traditional plastics. This development opens up new possibilities in the production of environmentally friendly materials. Above is a transparent film made from the new recyclable polymer developed in this study. Credit: Feng Li

Cellulose, widely sourced from plant matter, can be transformed into molecules for the creation of a novel category of recyclable polymers, offering a sustainable alternative to certain plastics.

Researchers at Hokkaido University have taken a significant step forward in the drive to make recyclable yet stable plastics from plant materials. This is a key requirement to reduce the burden of plastic pollution in the environment. They developed a convenient and versatile method to make a variety of polymers from chemicals derived from plant cellulose; crucially, these polymers can be fully recycled. The method was published in the journal ACS Macro Letters.

Cellulose is one of the most abundant components of biomass derived from plants, being a key part of the tough cell walls surrounding all plant cells. It can be readily obtained from plant wastes, such as straw and sawdust, therefore, using it as a feedstock for polymer manufacture should not reduce the availability of agricultural land for food production. Cellulose is a long-chain polysaccharide polymer, meaning that it is composed of multiple sugar groups, specifically glucose, linked together by chemical bonds.

Breakthrough in Polymer Synthesis

To make their new polymers, the Hokkaido team used two commercially available small molecules, levoglucosenone (LGO) and dihydrolevoglucosenone (Cyrene), which are made from cellulose. They developed novel chemical processes to convert LGO and Cyrene into a variety of unnatural polysaccharide polymers. Varying the precise chemical structure of the polymers offers the ability to generate different materials for a range of possible applications.

“Our biggest challenges were controlling the polymerization reaction that links the smaller monomer molecules together, and obtaining polysaccharides materials that are sufficiently stable for common applications while still able to be broken up and recycled by specific chemical conditions,” says Assistant Professor Feng Li, a corresponding author.

From left: Toshifumi Satoh, Yuta Mizukami, Feng Li, and Takuya Isono of the research team. Credit: Feng Li

Li adds that the biggest surprise during the research was the high transparency of the polymer films they made, which might be crucial for the kind of specialist applications that these polymers seem most suited for. “As the materials are quite rigid it may be difficult to use them as flexible plastic materials, such as plastic bags, so I expect they will be more suited for high-performance materials for optical, electronic, and biomedical applications,” Professor Toshifumi Satoh, the other corresponding author, adds.

Other research groups around the world are also exploring the potential for making plastic-replacing polymers from plants, and some such ‘bioplastics’ are already commercially available, but Satoh’s group has added a significant new opportunity to this fast-developing field.

The team now plans to explore further possibilities, but the feasible structural variations are so numerous that they would like to join forces with specialists in computational chemistry, artificial intelligence, and automated synthesis to explore the options.

“We hope this work will develop a wide variety of useful unnatural polysaccharide polymers to become part of a sustainable closed loop of synthesis from biomass with efficient recycling,” Li concludes.

Reference: “Chemically Recyclable Unnatural (1→6)-Polysaccharides from Cellulose-Derived Levoglucosenone and Dihydrolevoglucosenone” by Yuta Mizukami, Yuto Kakehi, Feng Li, Takuya Yamamoto, Kenji Tajima, Takuya Isono and Toshifumi Satoh, 9 February 2024, ACS Macro Letters.
DOI: 10.1021/acsmacrolett.3c00720

The study was funded by the Hokkaido University and the Fujimori Science and Technology Foundation.

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March 22, 2024
Groundbreaking New Method Transforms Plastic Trash Into Chemistry Treasure

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Hokkaido University researchers have developed a groundbreaking method to repurpose plastic waste by using it to initiate radical chain reactions for detoxifying hazardous chemicals. This approach, which enhances safety and efficiency while addressing the environmental issue of plastic waste, paves the way for sustainable and economically attractive chemical processes. Artistic depiction of extremely reactive molecules called radicals being generated from plastic fibers. Credit: Koji Kubota and Hajime Ito

Scientists use everyday plastics to initiate innovative chain reactions, developing a method to recycle plastic waste and improve both safety and efficiency in the process.

Single-use plastics are a major environmental concern, but now, rather than being disposed of as garbage, used plastic bags from the grocery stores could be utilized to carry out a reaction that can detoxify hazardous chemicals.

A team led by researchers at the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University has developed a method that uses common plastic materials instead of potentially explosive compounds to initiate radical chain reactions. This approach significantly increases the safety of the process while also providing a way to reuse common plastics such as polyethylene and polyvinyl acetate. These findings have been published in the Journal of the American Chemical Society.

(Top) General scheme for using mechanical force to trigger a radical chain reaction. (Bottom) Shreds of a grocery bag were utilized to initiate a reaction in a ball mill jar. Credit: Koji Kubota, et al. Journal of the American Chemical Society. December 22, 2023

Researchers utilized a ball mill, a machine that rapidly shakes a steel ball inside a steel jar to mix solid chemicals. When the ball slams into the plastic, the mechanical force breaks a chemical bond to form radicals, which have a highly reactive, unbonded electron. These radicals facilitated a self-sustaining chain reaction that promotes dehalogenation— i.e., the replacement of a halogen atom with a hydrogen atom—of organic halides.

Enhancing Chemical Processes

“The use of commodity plastics as chemical reagents is a completely new perspective on organic synthesis,” said Associate Professor Koji Kubota. “I believe that this approach will lead to not only the development of safe and highly efficient radical-based reactions, but also to a new way to utilize waste plastics, which are a serious social problem.”

Associate Professor Koji Kubota (left) and Professor Hajime Ito (right) of the research team at the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University. Credit: WPI-ICReDD

The reuse of waste plastic was demonstrated by adding plastic shreds of a common grocery bag to the ball mill jar and successfully carrying out the reaction. The team also showed their method could be applied to the treatment of highly toxic polyhalogenated compounds, which are widely used in industry. Polyethylene was employed to initiate a radical reaction that removed multiple halogen atoms from a compound commonly used as a flame retardant, thus reducing its toxicity.

Researchers anticipate this method will garner the attention of the industry due to its advantages in cost and safety.

“Our new approach using stable, cheap, and abundant plastic materials as initiators for radical chain reactions holds the significant potential to foster the development of industrially attractive, safe, and highly efficient chemical processes,” commented Professor Hajime Ito.

The study was funded by the Japan Society for the Promotion of Science, the Japan Science and Technology Agency, and the Ministry of Education, Culture, Sports, Science and Technology of Japan

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February 11, 2024
New Reversible Glue Promises To Change How We Recycle

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Engineers have developed a groundbreaking reversible glue, which promises to transform recycling processes. This environmentally friendly, water-based glue can easily detach labels from bottles, thus aiding in recycling and reducing landfill waste. Its development, in collaboration with Biffa, and its potential application across various industries, mark a significant advancement in adhesive technology.

Engineers at Newcastle University have developed a new glue that promises to change how we recycle.

Its reversible nature means it can be used for a multitude of purposes such as on the labels of bottles so that they are efficiently detached, making them easier to recycle. Labels will no longer need to be sent to landfill.

A Breakthrough in Adhesive Technology

The reversible glue, developed by experts from Newcastle University’s School of Engineering, is a water-based emulsion – a paint – that bonds together and can be separated by water that is either acidic or alkaline.

The glue uses polymers that contain electrical charge to both keep the emulsion stable and to stick to different surfaces. When a surface coated with a positively charged emulsion is joined to a surface coated with a negatively charged one, the two components stick together. However, if the bond is immersed in water that is either slightly acidic (pH2, about the same as lemon juice) or alkaline, it fails. This opens up possibilities for recycling, because it allows the separation on demand of components that have reached the end of their useful life.

A Collaboration for Sustainable Solutions

First author of the paper, Dr. Adriana Sierra-Romero, Research Associate at the School of Engineering, said: “We have been working with the waste management company, Biffa, and we have shown that with our glue, a propylene label stuck to a PET bottle can be removed by the wash water in their recycling plant. Although the bottles can be recycled, these labels are usually sent to landfill, so we know our technology can really make a difference. There will be many other industries where our glue can be used, and we look forward to working with other companies.”

The glue is based on current industrial processes – those for making a paint – and is developed from cheap materials so it can be scaled up easily. Because it is water-based it does not have the volatile organic solvents used in many commercial glues, but unlike other water-based adhesives, exposure to humid environments does not cause bond failure. The team has shown that its shelf life at room temperature is at least a year, so it is also inherently stable.

Eco-Friendly and Versatile Adhesive

The glue is targeted at plastic surfaces, but it can bond to other surfaces too. Plastics are where most applications are expective, and it is particularly effective at surfaces used in the packaging industry like polypropylene and polyethylene, which are inaccessible to many glues. Target industries include bottle recycling, but the work could be applied to other areas of packaging as well as the recycling of automotive parts or in electronics.

Published in the leading chemistry journal, Angewandte Chemie International Edition, the work was funded for by the Engineering and Physical Sciences Research Council (EPSRC). The team has recently been informed that the EPSRC will fund the research for another three years, bringing total funding for the team to £1M.

The lead investigator on the project, Professor Mark Geoghegan, Professor of Engineering Materials, added: “I first thought that charged polymers could be used for reversible adhesion back in 1999. Back then, this was blue sky research, and it is very exciting to see that we now have a glue based on these principles.”

Dr Katarina Novakovic, Reader in Polymer Engineering and co-investigator on the project said: “Companies are making more and more ambitious net zero targets. Our glue will help them achieve these.

“Newcastle University has a great record in sustainability. It is embedded in our curricula, for example, I am involved in teaching our undergraduate students about bottle recycling and they really enjoy this real-life example. It is great that we have a glue that can improve industrial processes in these areas.”

Reference: “A reversible water-based electrostatic adhesive” by Adriana Sierra-Romero, Katarina Novakovic and Mark Geoghegan, 29 October 2023, Angewandte Chemie International Edition.
DOI: 10.1002/anie.202310750

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December 30, 2023
From Cardboard Waste to Sustainable Foam: Revolutionizing Packaging

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This cardboard-based foam reinforced with gelatin could make packaging materials more sustainable. Credit: Jinsheng Gou

Eco-friendly cushioning foam made from recycled cardboard offers a stronger, more insulating alternative to traditional packaging materials, presenting a sustainable solution for the shipping industry.

With the holiday season in full swing, gifts of all shapes and sizes are being shipped around the world. But all that packaging generates lots of waste, including cardboard boxes and plastic-based foam cushioning, such as Styrofoam™. Rather than discard those boxes, researchers publishing in ACS Sustainable Chemistry & Engineering developed a cushioning foam from cardboard waste. Their upcycled material was stronger and more insulating than traditional, plastic foam-based cushioning.

Transforming Common Household Waste Into Eco-Friendly Materials

Among the many kinds of trash that accumulate within a home, wastepaper is one of the most common. Everything from newspapers and junk mail to paperboard envelopes and cardboard boxes can pile up, especially as internet shopping has exploded in popularity. Researchers are interested in turning these containers and paper waste into something else that’s useful — sturdy but light mailing materials.

Currently, to keep electronics and toys nestled tightly inside of a box, molded cushioning materials, such as Styrofoam, are typically used. A sustainable alternative could be lightweight, cellulose aerogels, but current methods to produce them from wastepaper require several chemical pretreatment steps. So, Jinsheng Gou and colleagues wanted to find a simpler way to make a wastepaper-based foam material that could withstand the roughest of deliveries.

Innovating Cardboard-Based Foam for Enhanced Protection

To create their foam, the team broke down cardboard scraps in a blender to create a pulp, then mixed it with either gelatin or polyvinyl acetate (PVA) glue. The mixtures were poured into molds, refrigerated, then freeze-dried to form cushioning foams. Both paper-based foams served as good thermal insulators and strong energy absorbers — even better than some plastic foams.

The team then created a heavy-duty version of their wastepaper foam by combining the pulp, gelatin, PVA glue, and a silica-based fluid that hardens as force is applied. This version of the cardboard-based foam withstood hits from a hammer without falling apart, and that result suggests the foam could be used in force-intensive deliveries, such as parachute-free airdrops.

The researchers say their work offers a simple yet efficient method to upcycle cardboard to create more environmentally friendly packaging materials.

Reference: “Biodegradable Wastepaper-Based Foam with Ultrahigh Energy-Absorbing, Excellent Thermal Insulation, and Outstanding Cushioning Properties” by Bin Zhang, Wenxuan Tao, Ziming Ren, Shiqi Yue and Jinsheng Gou, 28 November 2023, ACS Sustainable Chemistry & Engineering.
DOI: 10.1021/acssuschemeng.3c06230

The authors acknowledge funding from the Beijing Key Laboratory of Wood Science and Engineering.

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December 16, 2023