Sciencemadness Discussion Board

Polymerizations

Fleaker - 18-7-2010 at 13:36

I'd like to do a writeup with pictures of the synthesis of free radicals and alkoxyamine initiators and their subsequent use in controlled, living polymerizations of various vinyl-substituted monomers.

Is there an interest on this board for such a synthesis? I see very little polymerization chemistry, and even less on stable free radicals. I do not know why--much of the chemistry is fairly simple. I know Klute likes TEMPO, so perhaps I can also show the synthesis of this as well?

Any interest at all?


cynlabz - 18-7-2010 at 18:50

Yes, yes and yes! :D It all sounds like some very incredible chemistry, but again, as you mentioned, deceptively simple. There are numerous books and articles that detail syntheses of polymers like bakelite, nylons, and various complex polymer composites- the vast majority of these syntheses are easily accessible to the dedicated amateur.

If you would like, I have a beautiful old Dow Chemical publication at home, from a friend working in the field of polymer chem., which details the synthesis of various nanoparticles such as latex, polystyrene, etc. The best part is that some of these processes produce nanoparticles as large as 20 micrometers!!! This is in fact within the range of some common optical microscopes, allowing for beautiful viewing. Aside from the monomeric substrate (ie. styrene), the only other required chemicals are quite OTC; water (duh), potassium persulfate, and sodium dodecylbenzenesulfonate (SDBS). Dodecyl chloride, can also be utilised as a swelling agent, if one is interested in making really large uniform nanoparticles within the range described above. If you're interested, I'll give you the references. If you want some more theory on the topic, this could also be arranged, albeit I haven't even googled the topic and there must be other valuable refs lying about; I'm just trying to motivate people by advocating the simplicity of the matter.

It also happens to give some interesting synthetic tricks. The key thing to think on is the variety of interesting properties that can be embodied through alteration of the initial substrate. For instance, by controlling conditions, the benzene ring of polystyrene can be mononitrated to the nitrate, reduced to the amine with sodium dithionite, and finally, diazotised. This can allow you to couple various suitable aromatic compounds in a regioselective manner to the initial polystyrene (OTC). Alternatively proteins can be used as the diazotisation substrate (with the polystyrene coupling exclusively to the benzene rings of tyrosine, tryptophan and phenylalanine)- a whole variety of options are available.

I'm looking forward to any upcoming synthetic work, Fleaker :cool: Sorry if I've pulled this thread pretty far of topic; so people, what are your thoughts?

ps: If you want the refs soon, reply in the next couple of days, as I will be leaving for Vancouver shortly :D, and returning only in two weeks' time.

Cheers.

Panache - 13-8-2010 at 08:21

are you offering to scan in the book and post it clanbz, if you are then i encourage it as i want it!!

Fleaker, tempo it up i think, it would be very interesting