Your video is incredible! I want to know what if you synthesize biomolecules-RAFT polymer conjugates. I'm reading papers about this topic but I cannot understand deeply on some points. 1.) What should the structure be? (I mean the biomolecules (example protein) will connect between R-side and polymer or they will connect at the R-side or the structure may be different from these). 2.) What are benefits that we can receive from synthesizing these conjugates. ( I tried to search for this but I still don't get it. All I understand is that the synthesized polymers via this polymerization are structure controllable and MW predicable. ) Thank you
Thank you for your nice comment! I don't really have any experience in this area. One example is PEGylation (adding polyethylene glycol to a protein) can help improve stability/retention in the body. The following article from Sigma Aldrich appears to go over some of the different synthetic approaches: www.sigmaaldrich.com/US/en/technical-documents/technical-article/materials-science-and-engineering/drug-delivery/protein-and-peptide-polymer-conjugates
Excellent video on RAFT! Two quick question: 1) Why backfilled with nitrogen in the last freeze-pump-thaw cycle? 2) Can you please explain why oil bath is used?
Thank you for the nice comments. 1. I typically run my RAFT polymerizations under nitrogen. I know polymerizations can be performed under vacuum (common for anionic polymerizations). I’m not sure if a rubber septum would hold vacuum well enough to prevent air from getting the flask after a few hours. 2. We use oil baths in my lab to heat reactions. Specifically I used the oil bath because I used AIBN a thermal radical initiator, which has to be heated to ~65-80 degrees Celsius to produce sufficient radicals for polymerization to occur. A different type of radical initiator could be used to perform the reaction at ambient conditions.
1. When polymerizing under vacuum, it is difficult to take samples. It will be more difficult to obtain the desired monomer conversion, therefore, it is possible to make a mistake and get the wrong molecular weight of the polymer.
I made them in anisole, because I’d normally use it as a solvent for my polymerizations. Anisole is also high boiling so if stored cold the concentration won’t change much. Should be stable especially the CTA. if you have a reliable balance and doing reactions at large enough scale you could measure the CTA and AIBN directly.
I am a student in Japan. It was a very good video. If you don't mind, could you tell me how you calculated the required amount of CTA, AIBN, monomer and solvent? I would appreciate it if you could comment doi if you have any references that would help me with the method, etc.
Thank you. With RAFT you will typically calculate the DP of your polymer by multiplying monomer conversion by your M:CTA ratio. So if I used a 100:1 ratio and stopped at 50% conversion, the calculated DP would be 50. For the CTA:AIBN ratio 10:1 is commonly used. You want to use a relatively small amount of initiator that way most polymer chains are initiated by your CTA, retain living character, and to limit termination. As for solvent it depends on the polymerization, I've used 1:1 to 1:2 (M:S) but I have done some reactions without solvent as well. My advice would be to find a paper/patent that uses your monomer or similar one as a basis. If you have access to reaxys or scifinder they can be helpful tools for finding procedures pubs.acs.org/doi/10.1021/acs.macromol.1c02662 Page 4 in the supporting information has a detailed experimental procedure. pubs.acs.org/doi/10.1021/acs.macromol.7b00767 This is a good general reference about RAFT polymerization
@@MK-Chem Thank you very much for taking the time to reply to me." Does "M" mean monomer in both cases? Or is the second M derived from the mass of the reactant? Thank you very much for showing me the references. The first supporting info, which I see as your paper, is detailed and very helpful. I would like to use it with this video. Thank you.
So yes I meant M to stand for monomer in both cases. For M:CTA that is a molar ratio, so as an example 100 monomers per one CTA molecule. For the monomer:solvent ratio I meant mass ratio so for 1:1 I mean 3g of monomer and 3g of solvent. You're welcome, I'm glad you found them useful. Best of luck!
It can be just as effective as long as you have pure nitrogen or argon. I wouldn’t recommend it your monomer or solvent is very volatile. Freeze pump thaw is nice because it gives you a visual indication of degassing.
I quenched the reaction by cooling in an ice bath and opening to air. In this case I purified the polymer by precipitating it in a poor solvent a few times. When I have more time I hope to make additional videos covering the work up and characterization.
Your video is incredible!
I want to know what if you synthesize biomolecules-RAFT polymer conjugates.
I'm reading papers about this topic but I cannot understand deeply on some points.
1.) What should the structure be? (I mean the biomolecules (example protein) will connect between R-side and polymer or they will connect at the R-side or the structure may be different from these).
2.) What are benefits that we can receive from synthesizing these conjugates. ( I tried to search for this but I still don't get it. All I understand is that the synthesized polymers via this polymerization are structure controllable and MW predicable. )
Thank you
Thank you for your nice comment! I don't really have any experience in this area. One example is PEGylation (adding polyethylene glycol to a protein) can help improve stability/retention in the body. The following article from Sigma Aldrich appears to go over some of the different synthetic approaches: www.sigmaaldrich.com/US/en/technical-documents/technical-article/materials-science-and-engineering/drug-delivery/protein-and-peptide-polymer-conjugates
doesn't need to insert a needle at the rubber stopper for ventilation?
Also, please make videos on other polymerization methods with explaining the characterization data.
Excellent video on RAFT! Two quick question:
1) Why backfilled with nitrogen in the last freeze-pump-thaw cycle?
2) Can you please explain why oil bath is used?
Thank you for the nice comments.
1. I typically run my RAFT polymerizations under nitrogen. I know polymerizations can be performed under vacuum (common for anionic polymerizations). I’m not sure if a rubber septum would hold vacuum well enough to prevent air from getting the flask after a few hours.
2. We use oil baths in my lab to heat reactions. Specifically I used the oil bath because I used AIBN a thermal radical initiator, which has to be heated to ~65-80 degrees Celsius to produce sufficient radicals for polymerization to occur. A different type of radical initiator could be used to perform the reaction at ambient conditions.
1. When polymerizing under vacuum, it is difficult to take samples. It will be more difficult to obtain the desired monomer conversion, therefore, it is possible to make a mistake and get the wrong molecular weight of the polymer.
In what solvent you made the stock solution for CTA and AIBN ? And what is the half life of it ? Will it be stable for longer time ?
I made them in anisole, because I’d normally use it as a solvent for my polymerizations. Anisole is also high boiling so if stored cold the concentration won’t change much. Should be stable especially the CTA. if you have a reliable balance and doing reactions at large enough scale you could measure the CTA and AIBN directly.
I am a student in Japan. It was a very good video. If you don't mind, could you tell me how you calculated the required amount of CTA, AIBN, monomer and solvent? I would appreciate it if you could comment doi if you have any references that would help me with the method, etc.
Thank you. With RAFT you will typically calculate the DP of your polymer by multiplying monomer conversion by your M:CTA ratio. So if I used a 100:1 ratio and stopped at 50% conversion, the calculated DP would be 50. For the CTA:AIBN ratio 10:1 is commonly used. You want to use a relatively small amount of initiator that way most polymer chains are initiated by your CTA, retain living character, and to limit termination. As for solvent it depends on the polymerization, I've used 1:1 to 1:2 (M:S) but I have done some reactions without solvent as well. My advice would be to find a paper/patent that uses your monomer or similar one as a basis. If you have access to reaxys or scifinder they can be helpful tools for finding procedures
pubs.acs.org/doi/10.1021/acs.macromol.1c02662 Page 4 in the supporting information has a detailed experimental procedure.
pubs.acs.org/doi/10.1021/acs.macromol.7b00767 This is a good general reference about RAFT polymerization
@@MK-Chem
Thank you very much for taking the time to reply to me." Does "M" mean monomer in both cases? Or is the second M derived from the mass of the reactant?
Thank you very much for showing me the references. The first supporting info, which I see as your paper, is detailed and very helpful. I would like to use it with this video.
Thank you.
So yes I meant M to stand for monomer in both cases. For M:CTA that is a molar ratio, so as an example 100 monomers per one CTA molecule. For the monomer:solvent ratio I meant mass ratio so for 1:1 I mean 3g of monomer and 3g of solvent.
You're welcome, I'm glad you found them useful. Best of luck!
How effective is purging with nitrogen compared to degassing?
It can be just as effective as long as you have pure nitrogen or argon. I wouldn’t recommend it your monomer or solvent is very volatile. Freeze pump thaw is nice because it gives you a visual indication of degassing.
I am doing RAFT polymerization in my research. Do you happen to work with acrylamides?
I have a little bit of experience with acrylamides; I work mostly with acrylates/methacrylates.
How did you quench the reaction? Can you show the steps you did afterwards including characterization?
I quenched the reaction by cooling in an ice bath and opening to air. In this case I purified the polymer by precipitating it in a poor solvent a few times. When I have more time I hope to make additional videos covering the work up and characterization.
@@MK-Chem hello I am also working on polymers
And I am from India
What is the chemical structure of CTA.
In this example I used a trithiocarbonate. Similar to CAS# 870196-80-8