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1. Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 13:58:21 UTC Robert McNees

   Chemist Stephanie Kwolek was born #OTD in 1923.

   She invented Kevlar, used in high-strength / low-weight applications like body armor and airplane parts. She also invented the Nylon Rope Trick demo!

   Images: DuPont/Stephanie Kwolek

   • Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 14:29:34 UTC Robert McNees

     in reply to

     Here's an explanation and demonstration of Kwolek's "Nylon Rope Trick," which should be a key element in any proposed explanation of Spider-Man's web shooters.

     https://www.youtube.com/watch?v=jFM-iMyvg4c

   • Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 14:36:54 UTC Robert McNees

     in reply to

     Kwolek received her BS in Chem from Margaret Morrison Carnegie College of Carnegie Mellon.

     After graduating, she went to work for DuPont. She was asked to develop a suitable replacement for steel in radial tires, lightweight but strong, because of an expected gasoline shortage.
     
     This was after several people at DuPont turned down the project.

     Her group began their search in 1964, testing thousands of new polymers. "In the course of that work I made a discovery," she recalled.

   • Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 14:41:40 UTC Robert McNees

     in reply to

     Basically, she had a hunch.

     The solution that would lead to Kevlar was unlike most other polymer solutions, milky and thin rather than clear and viscous.

     "I think someone who wasn't thinking very much or just wasn't aware or took less interest in it, would have thrown it out."

   • Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 14:43:31 UTC Robert McNees

     in reply to

     The fellow who ran the spinneret – the solution is forced through a spinneret to make fibers – insisted it would clog the machine.

     But Kwolek convinced him to give it a try. The result was surprisingly strong. Suspecting a mistake, she tested it several times.

     Each time, tests on her new fiber indicated that it was roughly ten times stronger than anything else she had made. It was only then that she presented her results to DuPont.

     They refined the material, and introduced Kevlar in 1971.

   • Robert McNees (mcnees@mastodon.social)'s status on Wednesday, 31-Jul-2024 14:45:17 UTC Robert McNees

     in reply to

     Hydrogen bonding and stacking interactions between adjacent monomer chains in Kevlar make it about five times stronger than steel, by weight. It's used in everything from body armor to airplanes to race cars.

     I'm a big fan of Kwolek's philosophy of taking time to investigate things thoroughly, even (especially) if they don't work right away or give the expected result.

     "If things don't work out I don't just throw them out, I struggle over them, to try and see if there's something there."

   • seachanged@mastodon.social's status on Wednesday, 31-Jul-2024 19:15:32 UTC seachanged

     in reply to

     @mcnees

     Those are almost certainly Kevlar gloves she is wearing.

   • Robert McNees (mcnees@mastodon.social)'s status on Thursday, 01-Aug-2024 18:10:19 UTC Robert McNees

     in reply to

     • seachanged

     @seachanged Yep, I was careless with the alt-text. But I bet you are right.