“After we 3-D print, we restore the hydrogen bonding network through a sodium hydroxide treatment,” Pattinson says. “We find that the strength and toughness of the parts we get … are greater than many commonly used materials” for 3-D printing, including acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA).
How do thick-walled materials have their hydrogen bonds restored?
This process seems rather more involved than regular 3D printing.
But, well, if it's that simple, just soaking cellulose acetate in NaOH should have a huge number of applications. Maybe even more interesting than this 3D printer.
(Gotta try this at home later...)
We can already 3D print concrete. Centralized manufacturing still beats that all hands off... And people still insist on manually assembling bricks for a lot of reasons.
Only concern for me is it sounds like post-processing is required.
> As the acetone quickly evaporates, the cellulose acetate solidifies in place. A subsequent optional treatment replaces the acetate groups and increases the strength of the printed parts.
Polylactides (PLA) or polylactic acids represent a relatively new group of thermoplastics for packaging applications obtained from renewable resources. In extensive tests the functional and thermoforming properties of PLA are compared with those of other polymers. They are a biodegradable/compostable polyester manufactured from plant based resources. At 60°C and relative air humidity of 80% PLA will degrade completely after 60 days.
PLA's properties make it suitable for various thermoforming applications, particularly cups for cold bevarages and trays for fruit and vegetables. To produce high-molecular PLA, a process is used that is sustainable, solvent-free, and environmentally friendly.
PLA can be obtained from cassava, corn, maize, sugar beet, sugar cane, wheat, or agricultural byproducts containing natural plant sugars.
Although PLA has been known for more than a century, it has only been of commercial interest in recent years, in light of its biodegradability.
While PLA is one of the most promising bio-basedplastics, its main disadvantages are high price and unsatisfactory mechanical properties.
My understanding is that thermoforming is however only really utilized for sheet-based PLA material with essentially non-convex configurations. Also, it tends to degrade over 60 degrees celsius.
I wonder how this process and its output differs step-wise, limitation wise, and in terms of resulting material's mechanical properties. From the sounds of it, it's essentially a layering process and too early to judge limitations, though a small temperature range could perhaps be expected.
Here's a mirror: https://archive.fo/eoohY
Cellulose absent water is extremely inert, so inert that we use it as long term information storage, it is also an extremely good insulator.
You'd be more likely looking at using the cellulose as a non-conducting carrier than as part of the logic itself.
Would you be able to sacrifice some of the raw "speed" you gain from using electrical current to carry the signals in a traditional PCB if it meant you could work with significantly reduced heat? Or is my rudimentary understanding of the physics here betraying me? Friction is going to exist, so it's quite possible that these types of organic fluid logic gates would be useful for other reasons, but not in the ways I've imagined.
Without some(all?) of the electromagnetic changes associated with the continued reduction of die size for traditional electrical circuits, can you build significantly denser (and eventually more powerful) mechanical circuits with fluid-filled cellulose nanotubes?
Any kind of acidity would also be taboo. It would be very hard I think to make something like this but I'm more than willing to admit that none of these are 'dealbreakers'. That's why I asked about the application, after all, if that's the only way to do it and the application is valuable enough then maybe there is a reason to invest a large amount of $ for R&D.
It's still used for lots of things.
Cellulosic thermoplastics often appear in products where you don't want the plastic component to last forever, particularly textile fibers.
This 3D printing application seems similar to processes used to produce rayon and cellophane, but instead of producing the more universally useful fiber and sheet forms as a commodity, it forms an end-product directly and then stabilizes it chemically.
The cellulose polymer acts as hard plastic.