I prepared a certain concentration of the polymer and I want to know its molecular weight from its viscosity.
Thanks.
You need to specify the type of viscosity that your referred to. If you referred to intrinsic viscosity, then you can use the Mark Houwink equation. From the Mark-Houwink equation the relationship among the molecular weight and viscosity are given below:
[Ƞ] = KMα
Where Ƞ is the intrinsic viscosity , M is Molecular weight, K and α are constants for a particular polymer solvent system.
Dear Mohamed, there are some group contribution methods to predict the viscosity of polymers based on their structure. You might find some approaches in "The Properties of Gases and Liquids". If you have some measured results an interpolation of ln(viscosity) = c * Molecular Weight gives reasonable results.
You need to specify the type of viscosity that your referred to. If you referred to intrinsic viscosity, then you can use the Mark Houwink equation. From the Mark-Houwink equation the relationship among the molecular weight and viscosity are given below:
[Ƞ] = KMα
Where Ƞ is the intrinsic viscosity , M is Molecular weight, K and α are constants for a particular polymer solvent system.
Please have a look at the following introductory text: http://www.agilent.com/cs/library/primers/public/5990-7196EN.pdf
Hi Mohamed, Norazwani's answer is accurate, and I just want to add that if you're working with dilute solutions, you can use one set of Kappa and alpha values, but if you are working with a polymer melt, you will have a different k and a value. Normally you'd get three different samples of a polymer type with different MW's and measure their viscosity (either zero shear for a melt, or intrinsic for a solution) and plot log viscosity vs Log MW and that will give you a straight line with the gradient being "a" and the intercept being K. The preliminary MW's would be from a GPC measurement.
Dear sir,
You need to specify the type of viscosity that your referred to. If you referred to intrinsic viscosity, then you can use the Mark Houwink equation. From the Mark-Houwink equation the relationship among the molecular weight and viscosity are given below:
[Ƞ] = KMα
Where Ƞ is the intrinsic viscosity , M is Molecular weight, K and α are constants for a particular polymer solvent system.
Hello Mohamed Esmat I want to know how you calculated the molecular weight of the polymer? please answer me .. i have polymer and i want to calculate the Mw of it .
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