Nice day,
I want to measure the viscosity of a number of polyester polyols (as one of components of polyurethane). I know there are a broad range of polyester polyols for PU production, but could you propose me a viscosity range that is suitable for choosing a appropriate viscometer?
I've heard brookfield viscometer is OK, but I want to choose a reasonably priced and efficient model. For buying suitable model, I need to know range of viscosity.
Thank you for your time.
Dear Dr Alizadeh,
Please find attached a information leaflet selected almost at random for polyester polyols:
http://www.purinova.com/file_download,2,Folder
The viscosity range of between 500 and 25000 mPa.S, typically between 3000 and 12000.
As for the best Brookfield viscmeter type meeting your requirements it is best to consult the manufacturer or distributor, but the following link shows a viscometer which can be used for unsaturated polyester resins, not too far from your PUR application:
http://www.brookfieldengineering.com/education/applications/laboratory-unsaturated-polyester-resins.asp
The selection may depend on price, thermostatting capabilities, range of spindles etc. - please check with the manufacturer..
Dear Monirah,
please look at the data from Coim. there you find a good overview for viscosities as well for aliphatic (Diexter) oder aromatic (Isoexter) Polyesters with different structures and hydroxyl numbers. The molecular weight is 56100*functionality/hydroxyl number.
www.coimgroup.com
Dear Dr Gyorgy Banhegyi,
Many thanks for your reply.
Your sent information about viscosity range was so useful. It was closed to my knowledge from literature reviews. But my major question is that, any reactants (PA, TPA... as anhydride/acid or DEG, EG, glycerol... as glycol) will produce a product which has viscosity in this range?in the other word, due to broad range of reactants that can be used for poly ester polyol production, is the viscosity of product independent of reactants and the viscosity would be in this range?
Please accept my deepest thanks.
Monireh.
Dear Alisa Buchman,
thank you for your reply.
Could you please give me answer in mPa.s unit? Actually I need dynamic viscosity range.
Thanks & Rgds.
Monireh.
Dear Klaus Konejung,
Many thanks for your reply. your advise was so useful.
Please let me if I need your advice in future.
RGDs.
Monireh.
Dear Monireh Alizadeh,
The viscosity depends primarily on the molecular mass of the polyol. Secondary factors are the components (composition) which may influence the flexibility of the main chain. Branching may also be an influencing factor, as branched polymers tend to be more compact. The dependence of the viscosity on the moelcualr weight is described by the Kunh-Mark-Houwink equation, the chemical composition appear implicitly in the constant of this equation.
http://www.poliuretanos.com.br/Ingles/Chapter1/15Polyester.htm
A historical paper on the molecular mass distribution of polyesters prepared by polycondensation:
http://www.physics.emory.edu/faculty/roth/polymercourse/historical/Flory_JACS36.pdf
The literature review of the following PhD thesis may also be useful:
http://repositorio.ipl.pt/bitstream/10400.21/3933/1/Disserta%C3%A7%C3%A3o.pdf
The following is a literature review form RAPRA on various polyols:
https://www.smithersrapra.com/SmithersRapra/media/Sample-Chapters/Chemistry-and-Technology-of-Polyols-for-Polyurethanes,-2nd-Edition,-Volume-2.pdf
The next article compares the effect of the diacid used un polyeter polyols on polyurethane properties:
http://link.springer.com/article/10.1007/s11998-008-9121-9
I hope it helps
- Badges
- Science topic