Vista Normal

Hay nuevos artículos disponibles. Pincha para refrescar la página.
AnteayerSalida Principal

Fighting the Scourge of “Screwdriver Mange”

16 Agosto 2024 at 20:00

We’ve all got our favorite hand tools, and while the selection criteria are usually pretty subjective, it usually boils down to a combination of looks and feel. In our opinion, the king of both these categories when it comes to screwdrivers is those clear, hard acetate plastic handles, which are a joy to use — at least until the plastic starts to degrade and exude a characteristically funky aroma.

But perhaps we can change that if these experiments on screwdriver “mange” hold up. That’s [357magdad]’s unappealing but accurate description of the chemical changes that eventually occur in the strong, hard, crystal-clear handles of your favorite screwdrivers. The polymer used for these handles is cellulose acetate butyrate, or CAB, which is mostly the same cellulose acetate that replaced the more explode-y cellulose nitrate in things like pool balls and movie film, except with some of the acetate groups replaced with a little butyric acid. The polymer is fine at first, but add a little UV light and over time the outer layer of CAB decomposes into a white flaky cellulose residue while the butyric acid volatilizes, creating the characteristic odor of vomitus. Lovely.

In the video below, [357magdad] takes a look at different concoctions that all allegedly cure the mange. TL, DW; it was a dunk in household ammonia that performed the best, well ahead of other common agents like vinegar and bleach. The ammonia — or more precisely, ammonium hydroxide — works very quickly on the cellulose residue, dissolving it readily and leaving the handle mange-free and looking nearly new after some light scrubbing. None of the other agents came close, although acetone did manage to clear up the mange a bit, at the cost of softening the underlying CAB in a process that’s probably similar to acetone smoothing ABS prints.

As for the funky smell, well, the results were less encouraging. Nothing really got rid of the pukey smell, even a roll in baking soda. We suspect there won’t be much for that, since humans can detect it down to 10 parts per million. Consider it the price to pay for a nice-looking screwdriver that feels so good in your hand.

Lasers Could Help Us Recycle Plastics Into Carbon Dots

Por: Lewin Day
18 Julio 2024 at 11:00

As it turns out, a great deal of plastics are thrown away every year, a waste which feels ever growing. Still, as reported by Sci-Tech Daily, there may be help on the way from our good friend, the laser!

The research paper  from the University of Texas outlines the use of lasers for breaking down tough plastics into their baser components. The method isn’t quite as simple as fire a laser off at the plastic, though. First, the material must be laid on a special two-dimensional transition metal dichalcogenide material — a type of atomically-thin semiconductor at the very forefront of current research. When the plastics are placed under the right laser light in this scenario, carbon-hydrogen bonds in the plastic are broken and transformed, creating new chemical bonds. Done right, and you can synthesize luminescent carbon dots from the plastic itself!

“By harnessing these unique reactions, we can explore new pathways for transforming environmental pollutants into valuable, reusable chemicals, contributing to the development of a more sustainable and circular economy,” says Yuebing Zheng, a leader on the project. “This discovery has significant implications for addressing environmental challenges and advancing the field of green chemistry.”

Sure it’s a bit trickier than turning old drink bottles into filament, but it could be very useful to researchers and those investigating high-tech materials solutions. Don’t forget to read up on the sheer immensity of the world’s plastic recycling problems, either. If you’ve got the solution, let us know!

❌
❌