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Environment

Today's discarded clothing could end up in tomorrow's stronger paper

By Ben Coxworth
February 28, 2025
Today's discarded clothing could end up in tomorrow's stronger paper
From left, researchers Alexander Weissensteiner, Alexander Wagner and Thomas Harter with a paper sample consisting of 30% recycled cotton fibers
From left, researchers Alexander Weissensteiner, Alexander Wagner and Thomas Harter with a paper sample consisting of 30% recycled cotton fibers
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Shredded cotton clothing gets soaked in an aqueous solution prior to milling
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Shredded cotton clothing gets soaked in an aqueous solution prior to milling
From left, researchers Alexander Weissensteiner, Alexander Wagner and Thomas Harter with a paper sample consisting of 30% recycled cotton fibers
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From left, researchers Alexander Weissensteiner, Alexander Wagner and Thomas Harter with a paper sample consisting of 30% recycled cotton fibers

While it's great that many types of paper can now be recycled, textile waste is still mostly just dumped or burned (with a few experimental exceptions). A new technique could change that by combining the two materials, using discarded cotton clothing to boost the strength of packaging paper.

The process is being developed at Austria's Graz University of Technology, by a team led by postdoctoral researcher Thomas Harter.

It begins with discarded cotton-based clothing being mechanically ripped into shreds and then combined with a water-based solvent solution. That mixture is subsequently milled in order to pull apart the interwoven cotton fibers without allowing them to clump together or form knots.

The resulting fibrous slurry is claimed to be much like the pulp used in paper-making. In fact, the substance gets added to the recycled-paper pulp utilized in the production of packaging papers such as cardboard, boosting the strength of the finished product.

Shredded cotton clothing gets soaked in an aqueous solution prior to milling
Shredded cotton clothing gets soaked in an aqueous solution prior to milling

Lab tests have reportedly shown that even when the enhanced paper contains just 30% textile fiber, it's still significantly stronger than packaging paper made purely from recycled-paper fiber. This is because at average 1.7 mm in length, the textile fibers are much longer than their paper counterparts. Both cotton fibers and the wood fibers traditionally used in paper-making are mainly composed of cellulose.

Importantly, the boosted packaging paper can be processed just like regular paper. It does have a brownish color which is interspersed with colored specks from color-dyed fabrics, but that characteristic has no effect on its performance.

It is hoped that once the technology is developed further, it could divert textile waste from going to landfills, produce stronger packaging paper that lasts longer before needing to be recycled, and reduce the amount of discarded paper needed for the production of packaging paper.

Harter and colleagues are now exploring methods of scaling the technology up for industrial usage, part of which will involve reducing the energy requirements for the milling process. This could be facilitated by pretreating the shredded fabric with enzymes, which would allow the cotton fibers to fall apart more easily.

Source: TU Graz

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EnvironmentTU GrazRecyclingPaperTextileClothingWaste
4 comments
Ben Coxworth
Ben Coxworth
Based out of Edmonton, Canada, Ben Coxworth has been writing for New Atlas since 2009 and is presently Managing Editor for North America. An experienced freelance writer, he previously obtained an English BA from the University of Saskatchewan, then spent over 20 years working in various markets as a television reporter, producer and news videographer. Ben is particularly interested in scientific innovation, human-powered transportation, and the marine environment.

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Tech Fascinated
Sounds great, but certainly not new. Fibers from rags are used in paper already. From Britannica online: "Papermaking can be traced to about ad 105, when Ts’ai Lun, an official attached to the Imperial court of China, created a sheet of paper using mulberry and other bast fibres along with fishnets, old rags..."
paul314
All things old are new again. Almost all paper was "rag paper" before the development of wood-pulp mills for mass printing, and rag is still available for printed things that need to be durable, like archival copies or currency. Rag went out because it was cheaper to cut down and pulp zillions of acres of softwoods to turn them into paper and then plant with more softwoods in plantations mostly free of other trees or animals. Now end-of-life clothing isn't rare, it's a glut we don't know what to do with, and softwood clearcutting has turned out to be less than ideal, so the pendulum swings back.
(Btw, rag vs pulp is why many books from the 1800s are still in pretty good condition still, and books and magazines from the mid-20th century tend to crumble when you read them. Turns out pulp makes for weaker paper, and pulp-making tends to leave decay-inducing acids behind.)
TechGazer
Collecting, sorting, and transporting the discarded clothing from consumers isn't simple or cheap. I could see this being used for industrial sources of cotton waste, a reasonable distance from a paper recycling plant.
davidmiller
Althought the formula is closely guarded, most all paper money his a fair amount of rag content for durability.