I have been doing ATRP polymerization of MMA on the surface of nanoparticle. During the polymerization I have to degas the flask by freeze-pump-thaw. I have been looking for a proper vacuum pump to buy, so that I want to know what is the normal range of pressure during this process in order to pick a good one?
Suitable vacuum-pump is http://www.vacuubrand.com/en/page717.html VACUUBRAND is really "working horse" for chemical laboratory. Reliable and some noisy.
LEYBOLD and PFEIFFER are quiet and sensitive to contaminations (but they are best for measuring and analytical equipment) , EDWARDS is well known as trash ( because of blocking).
Dear all,
much care should be given to the freezing point and the volatility of the polymerization ingredients. I don't know if you are using liquid nitrogen or a cryostat bath for freeze-thaw cycling. If the freezing is really perfect than the pump will be an ordinary one from the economic/performance point of view. Regards
Sorry, I forgot to advise you to work on a Shlenck set-up if available. Regards
We use Welch® Direct-Drive High Vacuum Pumps, Model 8907. Pressure is ~ 1 x 10-4 Torr.
https://us.vwr.com/store/catalog/product.jsp?catalog_number=55009-084
We use for degassing the polymeric samples before modification with radio-frequency plasma and ESR measurements the High-Vacuum pump (Czech production) working at the pressure 0.1 Pa.
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