A new method chemically breaks down old fabric and reuses polyester compounds to create fire-resistant, anti-bacterial or wrinkle-free coatings that can then be applied to new clothes and fabrics.
With a goal of giving textile waste new life, Cornell University researchers
have found a way to chemically break down old clothing and reuse polyester
compounds to create fire-resistant, anti-bacterial or wrinkle-free coatings that
can then be applied to new clothes and fabrics.
The proof-of-principle
study provides
hope for the unsustainable textile, apparel and footwear industries — which
together generate 20 percent of global solid waste; the Ellen MacArthur
Foundation
estimates 73
percent of all textiles end up incinerated or in landfill. Many so-called
recyclers end up illegally dumping textiles as trash in countries in Asia and
Africa; and many other brands and companies just incinerate the
materials
— which releases greenhouse gases, dioxins and toxic substances into the
environment.
"We think that our clothes are recycled or reprocessed; but most of the time
they are actually sent to other places as solid waste," said Juan
Hinestroza, professor of fiber
science and apparel design and director of Cornell’s Textiles Nanotechnology
Laboratory. "Our main goal is to offer a pathway to reuse this material."
Blended textiles — typically comprised of natural fabrics such as cotton and
synthetic fabrics such as polyester — have until recently stymied textile
recyclers, which lacked the ability to easily separate the fibers for
reuse. Recent innovations from startups such as Circle
Economy,
Protein
Evolution
and Worn
Again
have removed this barrier — enabling easy separation and recycling of pesky
blended textiles for reuse.
Everything you need to know about the state of play in molecular recycling
Join us as Katherine Hofmann, Sustainability Strategic Initiatives Manager at Eastman, explores the potential for this new recycling category to help fuel a circular economy for plastics - Wed, Oct. 16, at SB'24 San Diego.
But the Cornell study, which was partially funded by the National Science
Foundation, may be the first to upcycle old textiles into a number of
high-performance coatings for new textiles. Upcycling of Dyed Polyester
Fabrics into Copper-1, 4-Benzeedicarboxylate Metal-Organic Frameworks —
published March 30 in the journal Industrial & Engineering Chemistry
Research — describes the process of cutting textiles into pieces and
chemically decomposing them into a soup of raw materials, dyes, additives, dirt
and esters. A metal solution is added and building blocks from the polyester
share an affinity with the metal, and selectively link together metal compounds
forming tiny cages (called metal-organic frameworks or MOFs) that settle
to the bottom of the soup.
The cages that form are then used to make coatings, which may require minor
structural tweaks to tailor each to specific uses — including coatings that keep
permanent press apparel from wrinkling, antibacterial coatings for surgical
gowns or scrubs, or fire-retardant coatings for baby or industrial clothes or
furniture.
"One goal of my lab is to create a universal coating that will serve all these
purposes; though we are still far away from that," said Hinestroza, who
co-authored the paper with Yelin
Ko, a doctoral student at
Cornell’s Department of Human-Centered Design; and Tyler
Azbell and Phillip
Milner, from the
University’s Department of Chemistry and Chemical Biology.
Hinestroza and Ko began working on a circular uses for discarded
polyester
in 2022. By converting polyester into MOFs, they have been able to repurpose the
porous MOFs into an array of uses. Previous research attempts required the use
of harsh solvents, but Hinestroza has discovered a process that takes just 30
minutes and requires no extreme chemicals or temperatures. MOFs have a cage-like
structure that can capture molecules. When MOFs are electrospun into nanofiber,
they can be used in medical textiles and protective apparel, gas-separation or
even drug-delivery applications. Already applicable to both dyed and undyed
fabric, Hinestroza’s Lab is now demonstrating that the new MOF-treated material
can create MOFs again and again, creating a circular polyester loop that will divert the materials from landfill — and potentially offering non-toxic alternatives
to these common, conventionally harmful chemical
coatings.
Prior to this research, some believed the dyes and impurities in the mix would
interfere with the process, but this proof of principle of the method — known as
controlled crystallization — shows that the polyester-derived linkers can seek
out and attach to metal compounds in solution, in spite of other materials that
may be present.
The research describes a closed-loop process, where discarded materials may be
reused and contribute to a circular economy — a focus for many sustainability
researchers at Cornell, Hinestroza said.
Published May 3, 2023 2pm EDT / 11am PDT / 7pm BST / 8pm CEST
Sustainable Brands Staff
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