Tag Archives: Polyethylene

Cheap plastics could soon be turned into sustainable fabrics

Every year, the textile industry produces 62 million tons of fabrics. It’s one of the most polluting industries on Earth, second only to the oil and gas industry, using massive amounts of water and generating a lot of waste in the process. But it could become a bit more sustainable by incorporating plastic and using it as fabrics.

Plastic made fabrics. Image credits: Svetlana Boriskina.

In April 2016, world leaders gathered in Paris to sign an agreement to curb global greenhouse gas emissions. At the major event, mixed between countless press conferences and presentations, one small stand showed how plastic could be used to make fabric. The resulting fabric is surprisingly soft and durable, and a great way to repurpose plastic. The idea got lost in the great turmoil caused by the Paris Agreement — but it warrants more attention, researchers say.

The fashion industry is responsible for 5-10% of global greenhouse gas emissions. It’s not just manufacturing — maintenance and chemical treatments often consume even more energy (and water) than the production phase. But polyethylene yarns are resistant by default.

Svetlana Boriskina and colleagues at MIT focused on polyethylene because it is one of the most commonly used plastics. It’s lightweight and durable, which makes it excellent as a packaging material, but horrendous as a pollutant. Its uses rang for films, tubes, plastic parts, etc — and it’s still widely used throughout the world.

Sweater knitted by Emily Holtzman, who is also modelling it. Image courtesy of Svetlana Boriskina.

Polyethylene (PE) can be colored cheaply through environmentally friendly methods and is durable, offering exactly the type of properties you want in clothing. It offers the potential to create sustainable fabrics, Boriskina says, and the whole process is quite cheap.

“The process of converting PE materials to textiles is indeed cost-effective, scalable and eco-friendly,” Boriskina explains for ZME Science. “Even starting from fossil PE provides a more environmentally-friendly textile solution, but there is also a possibility to recycle vast amounts of already accumulated PE waste into high-added-value-products such as fabrics and garments. Finally, it has been shown that PE can be derived from biomass, making the fabrics bio derived yet completely recyclable.”

A close-up of the plastic-made fabrics. Image credits: Svetlana Boriskina.

Using plastic for clothes isn’t as crazy as it seems. Throughout history, the textile industry generally made use of natural fibers such as wool, cotton, silk, and linen. In the past century, however, synthetic materials such as polyester and nylon have become a common occurrence. Polyethylene has been generally overlooked until now.

The authors found that PE fabrics are resistant to staining and allow for fast drying, as well as efficient moisture-wicking. These properties, along with the cheap price and durability, make PE an excellent alternatives for existing fabrics.

“This work shows that not only the full lifecycle analysis confirms that PE is more environmentally friendly than other materials, but also the alternative way of dry-coloring further reduces the environmental footprint and allows adding other properties to the fabrics beyond color,” Boriskina tells me.

Finally, the conversion process from plastic to textiles is also cheap and scalable, and it’s possible to use plastic already accumulating in waste sites.

“The process of converting PE materials to textiles is indeed cost-effective, scalable and eco-friendly. Even starting from fossil PE provides a more environmentally-friendly textile solution, but there is also a possibility to recycle vast amounts of already accumulated PE waste into high-added-value-products such as fabrics and garments. Finally, it has been shown that PE can be derived from biomass, making the fabrics bio-derived yet completely recyclable,” Boriskina adds.

Image credits: Svetlana Boriskina.

Polyethylene seems like a truly well-suited material for clothes. But will it catch on? The fashion industry is often unpredictable and it doesn’t often choose the most sustainable or efficient materials. But PE has an advantage that could make it more attractive, especially in the summer.

“It is literally cool to wear our PE textiles, and the pun is intended. The fabric offers a ‘cold touch’ tactile sensation and keeps the wearer cool, dry, and comfortable,” Boriskina concludes.

As of 2017, over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market.

The study “Sustainable polyethylene fabrics with engineered moisture transport for passive cooling” has been published in Nature Sustainability.

LEGO launches functioning wind turbine model to promote sustainability

LEGO wants you to build wind turbines — one eco-friendly plastic block at a time.

Lego windmill.

Image credits LEGO.

Danish toy manufacturer LEGO teamed up with turbine manufacturer Vestas to create a toy turbine set that you need to assemble, but actually works! Oh, and the blocks are built using LEGO’s new sustainable production process.

The 826-piece turbine stands 1 meter (0.3 feet) high when completed. The kit was reportedly made exclusively for Vestas back in 2008 and will now go on sale to the public on November 23.

Toymill

Lego windmill 2.

Image credits LEGO.

The turbine (once completed) boasts three adjustable blades that rotate — the set includes a motor to spin them — and built-in aircraft warning lights. The vista is further fleshed out by a house, patio, mailbox, flower beds, and a white picket fence, all of them pleasantly rural.

Turbines obviously need turbine workers, so LEGO is also throwing a Vestas van, two service technicians with safety helmets, a lady (who, presumably, inhabits the house underneath the turbine), and a dog (presumably the lady’s pet).

Lego did not remain oblivious to the irony of building a model promoting sustainability from unsustainable materials. The kit’s blocks were cast from a new, sugarcane-based plastic that LEGO announced earlier this year. The material, polyethylene, is softer than the traditional plastic LEGO used, but it’s hardy and, according to the company, the blocks are “technically identical to those produced using conventional plastic”.

“We strive to make a positive impact on the environment and are committed to climate action and to use sustainable materials in products and packaging,” said Tim Brooks, Vice President of Lego’s Environmental Responsibility Group. “This wind turbine celebrates our first steps in bringing these ambitions to life and we hope it will inspire builders to learn about renewable energy.”

“Today, wind energy is the cheapest source of energy in many markets, which have made wind turbines a sustainability icon across the globe and we are proud to partner with the LEGO Group on this relaunch,” said Morten Dyrholm, Group Senior Vice President of Marketing, Communications and Public Affairs at Vestas.

Dyrholm explains that Vestas requested the model specifically to promote wind energy to a small audience within the energy sector. He adds that today’s relaunch of the LEGO set for a global audience “tells the story of how wind energy [has] gone from niche to mainstream, not just within energy but the entire world”.

The new kit — along with the plant-based plastic bricks — are part of LEGO’s drive to implement sustainable materials in their packaging by 2025 and their products by 2030.

Additive recycles incompatible mixed plastics into uber-polymer

A new four-block polymer could finally allow for chemically-incompatible plastics to be recycled together. The best part? The resulting material has better physical properties than either of the materials taken individually.

Image credits Hans Braxmeier.

Cornell University Professor of chemistry Geoffrey Coates is a big believer in plastic recycling. He often gives talks on the subject, and routinely starts these off with a simple question: How much of the 78 million tons of plastic used for packaging each year gets recycled and re-used by the industry?

A world wrapped in plastic

The answer is ‘depressingly little’ — just over 2%. A third of the total quantity gets leaked into the environment, he adds, some 14% goes to incinerators or other energy recovery methods, and the lion’s share — 40% — finds its way into landfills. Where it will stay virtually forever.

One of the biggest problems, he goes on to explain, is that the two most common types of plastics — polyethylene (PE) and polypropylene (PP), which account for two-thirds of all plastics — are chemically incompatible and can’t be processed together.

But work performed in Coates’ lab may finally change that. He and his team have collaborated with researchers from the University of Minnesota to develop a new polymer that can reconcile PE and PP. A small quantity of this substance can bind the two plastics into a new, mechanically tougher polymer.

Their additive is a four-block polymer, constructed of alternating PE and PP segments. It resembles a chemical zipper of sorts, each segment tying to one of the two polymers. To test how strong the resulting material is, the team compared it to available diblock (two-block) polymers. For the tests, they welded together two strips of plastic with different polymer adhesives then pulled them apart to see how much strain the weld can take.

Welds made with diblock polymers failed relatively quickly, but the new tetrablock polymer held so well that the plastic strips before it gave way.

 

 

“People have done things like this before,” Coates said, “but they’ll typically put 10 percent of a soft material, so you don’t get the nice plastic properties, you get something that’s not quite as good as the original material.”

“What’s exciting about this is we can go to as low as 1 percent of our additive, and you get a plastic alloy that really has super-great properties.”

Better living through chemistry

Image credits Michael Schwarzenberger.

While the tetrablock polymer was intended to allow wide-scale plastic recycling, it may go above and beyond the call of duty says James Eagan, a postdoc researcher in Coates’ team and lead author of the paper. The additive could usher in a whole new class of tougher polymer blends, allowing for wider applications and improving sustainability in one shot.

“If you could make a milk jug with 30 percent less material because it’s mechanically better, think of the sustainability of that,” he said. “You’re using less plastic, less oil, you have less stuff to recycle, you have a lighter product that uses less fossil fuel to move it.”

Although ideal, a world where all the plastics we use is recycled sadly remains an unreachable goal. But between this new polymer and previous work on bio-degradable plastics, we definitely have the tools to start undoing — or at least capping — the damage polymers have wrought on the planet. Both technologies are still far from perfect, but they’re workable. There are also policy measures which have shown effectiveness in limiting this pollution in the first place — such as taxes, alternative material use, and outright bans. Let’s hope they’re all put to good use removing plastic waste sooner rather than later.

The full paper “Combining polyethylene and polypropylene: Enhanced performance with PE/ i PP multiblock polymers” has been published in the journal Science.