4 ms·

Link to the paper (paywalled): http://www.sciencemag.org/content/344/6185/732 http://www.sciencemag.org/content/344/6185/732 It be interesting to see how bioco

Link to the paper (paywalled): http://www.sciencemag.org/content/344/6185/732 http://www.sciencemag.org/content/344/6185/732 It be interesting to see how biocompatible and what the durability of these material is. One of the problems with current generation of joint implants is that nearly all of the materials we use (for biocompatibility, corrosion resistance, and durability reasons) are all way stiffer than the material (bone or cartilage) that they replace, resulting in stress shielding in bone, and increased wear at contact surfaces in joints (especially when you only have a one sided replacement). If Titan (god, I hope they give it a better name) turns out to play nice in the body and is sufficiently durable, it could be pretty interesting to see what happens to implant design in the future.

shoyer 12y ago
This link makes much more sense now that I see that the article is already published rather than being submitted to Science. Journals like Science and Nature have strict policies of not publishing papers if the results have already been publicized by the authors.
twic 12y ago
Right, so if i've got this right, 4,4'-oxydianiline is this (pairs of parens are supposed to be circles denoting benzene rings; apologies for writing out the carbons, i can't do plain hexagons): C - C C - C / \ / \ H2N-C ( ) C-O-C ( ) C-NH2 \ / \ / C - C C - C The paraformaldehyde does its job as monomeric formaldehyde (the double quote is a double bond running vertically, horrific i know): O " HO-C-OH And the polymerisation is a straightforward condensation of the formaldehyde with one of the amines, so the monomer is: C - C C - C O / \ / \ " ...-NH-C ( ) C-O-C ( ) C-NH-C-... \ / \ / C - C C - C And here's a monomer with a bit of its neighbourhood: - C O C - C C - C O C - \ " / \ / \ " / ) C-NH-C-NH-C ( ) C-O-C ( ) C-NH-C-NH-C ( / \ / \ / \ - C C - C C - C C - There's nothing really radical in terms of the building blocks, but it's a novel combination. Cool. I had never come across oxydiamine before, but i get the impression it's a common component in polymers, and it looks fairly boring and inert. I guess it's not a single big aromatic system, right? Wrong number of electrons. The reason this is described as a "hemiaminal" is because the formaldehyde carbon can do keto-enol tautomerism and turn into this: - C OH C - \ | / ) C-NH-C-NH-C ( / | \ - C OH C - Which has hydroxyl groups and nitrogens on the same carbon, and so is a hemiaminal. I couldn't figure out the "further cyclize at high temperatures, producing poly(hexahydrotriazine)s", though. Does that mean cyclising using linkages like this? Or is there some way the chains can crosslink?
- bigd 12y ago
  those drawings are beautiful. how you did it? babel?
  - twic 12y ago
    I just typed a lot of letters, punctuation marks, and spaces into the text area. Mostly spaces.

shoyer 12y ago

This link makes much more sense now that I see that the article is already published rather than being submitted to Science. Journals like Science and Nature have strict policies of not publishing papers if the results have already been publicized by the authors.

twic 12y ago

Right, so if i've got this right, 4,4'-oxydianiline is this (pairs of parens are supposed to be circles denoting benzene rings; apologies for writing out the carbons, i can't do plain hexagons): C - C C - C / \ / \ H2N-C ( ) C-O-C ( ) C-NH2 \ / \ / C - C C - C The paraformaldehyde does its job as monomeric formaldehyde (the double quote is a double bond running vertically, horrific i know): O " HO-C-OH And the polymerisation is a straightforward condensation of the formaldehyde with one of the amines, so the monomer is: C - C C - C O / \ / \ " ...-NH-C ( ) C-O-C ( ) C-NH-C-... \ / \ / C - C C - C And here's a monomer with a bit of its neighbourhood: - C O C - C C - C O C - \ " / \ / \ " / ) C-NH-C-NH-C ( ) C-O-C ( ) C-NH-C-NH-C ( / \ / \ / \ - C C - C C - C C - There's nothing really radical in terms of the building blocks, but it's a novel combination. Cool. I had never come across oxydiamine before, but i get the impression it's a common component in polymers, and it looks fairly boring and inert. I guess it's not a single big aromatic system, right? Wrong number of electrons. The reason this is described as a "hemiaminal" is because the formaldehyde carbon can do keto-enol tautomerism and turn into this: - C OH C - \ | / ) C-NH-C-NH-C ( / | \ - C OH C - Which has hydroxyl groups and nitrogens on the same carbon, and so is a hemiaminal. I couldn't figure out the "further cyclize at high temperatures, producing poly(hexahydrotriazine)s", though. Does that mean cyclising using linkages like this? Or is there some way the chains can crosslink?

bigd 12y ago
those drawings are beautiful. how you did it? babel?
- twic 12y ago
  I just typed a lot of letters, punctuation marks, and spaces into the text area. Mostly spaces.