ERROR 1
ERROR 1
ERROR 2
ERROR 2
ERROR 2
ERROR 2
ERROR 2
Password and Confirm password must match.
If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)
ERROR 2
ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.
The technology for producing ultra-high-molecular-weight polyethylene (UHMWPE) fibers has existed for nearly four decades. Two companies, DSM and Honeywell, use it to manufacture most of the world’s supply of the lightweight fibers, which are twice as strong as steel and are used in bulletproof clothing, armor, marine towlines, and other applications.
Now Paul Smith and Theo Tervoort of the ETH Zurich and coworkers have found a way that might greatly improve the manufacturing process (Macromolecules 2015, DOI: 10.1021/acs.macromol.5b02211).
The new study proposes replacing the solvent currently used, petroleum-based decalin, with environmentally benign vegetable oils. This solvent switch, according to the study, could increase fiber strength nearly 100% or cut production costs by more than 50%.
“This is a revolutionary discovery in the field of high-strength fibers and will have a very significant societal impact,” says Macromolecules Associate Editor Alan D. English of the DuPont Experimental Station. “It’s the most significant discovery in fiber science in nearly a half-century.”
Conventional polyethylene, the world’s most common plastic, is weak because its fibers are short. To make UHMWPE fibers, manufacturers polymerize ethylene monomer into chains about 30 times as long as those of conventional polyethylene. Those chains are initially entangled with one another, which also weakens the polymer, so manufacturers dissolve them in decalin and then draw them out lengthwise to remove some entanglements. The solution used commercially is 10% polyethylene and 90% decalin by volume—meaning that for every kilogram of UHMWPE fiber produced, 9 kg of decalin has to be recovered.
In the new study, the researchers found they could prepare UHMWPE by using 25% polyethylene and 75% vegetable oil, so only 3 kg of environmentally benign—in fact, edible—solvent needs to be recovered for every kilogram of UHMWPE produced, lowering production costs. A solution of 10% polyethylene and 90% vegetable oil enabled further disentanglement and yielded stronger fibers than those made with the decalin-based method.
Pieter Lemstra, a professor emeritus at Eindhoven University of Technology (TUE), who codiscovered the current UHMWPE manufacturing process with Smith, notes that changing the current industrial process could prove challenging. Nevertheless, the new study is “a scientific breakthrough,” he says.
“Given the mature status of the high-performance fiber industry, the huge markets, big profits, and growing competition, this achievement cannot be regarded as just peanuts,” notes TUE professor emeritus Han Meijer, who perfected DSM’s UHMWPE manufacturing process. “It is an unexpected, huge effect.”
Join the conversation
Contact the reporter
Submit a Letter to the Editor for publication
Engage with us on Twitter