What is Mark Houwink Sakurada equation?
What is Mark Houwink Sakurada equation?
(1) [ η ] = KM v a where [η] is the intrinsic viscosity, Mv the viscosity-average molecular weight, and K and a, are the constants for a given solute–solvent system.
How do you find the molecular weight of a chitosan?
The relative molecular weight of the left part and right part of chitosan repeated monomer are 203.2 and 161.2 respectively [27], then the average molecular weight (Mo) of the monomer was calculated by the formula of 161.2 (DD) + 203.2 (1-DD).
How do you calculate molecular weight from viscosity?
In this method viscosity of liquid is measured by comparing the flow times of two liquids of equal volumes using same viscometer. The molecular weight of the polymer is measured by using viscometer and the molecular weight obtained by this technique is called viscosity average molecular weight.
What is Mark Houwink parameters?
Mark-Houwink parameters used are “k” = 2.79 x 10-3 cm3/g and “a” = 1.2754 at 25°C, data obtained from Tinland and Rinaudo [25] (Dependence of the Stiffness of the Xanthan Chain on the External Salt Concentration.
What is Huggins constant?
The constant kH is termed the Huggins constant and has values ranging from 0.3 in good solvents to 0.5 in poor solvents. It contains information about hydrodynamic and thermodynamic interactions between coils in solution.
What is the chemical formula of chitosan?
At a minimum deacetylization level of 70% (=amount of free amino groups in the polymer) it is considered to be chitosan. The monomer of chitosan is D-amino glucose….Chitosan.
| Chemical name: | (1,4)-2-Amino-2-desoxy- beta-D-glucan |
|---|---|
| Empirical formula: | (C6H11NO4)n |
| CAS: | 9012-76-4 |
How do you identify chitosan?
The unknown composition can be determined by plotting a graph for the time of flow and compositions. The molecular weight of the polymer is measured by using viscometer and the molecular weight obtained by this technique is called viscosity average molecular weight.
What method is used to calculate molecular weight polymers?
Therefore, in order to determine the molecular weight and molecular weight distribution of a polymer, one of the most widely applied methods is gel-permeation chromatography. Gel permeation chromatography (GPC) is a term used for when the separation technique size exclusion chromatography (SEC) is applied to polymers.
What is the relation between molecular weight and viscosity?
The larger the polymer, the more drag and also the more intermolecular attraction, and so the higher the viscosity. So, the viscosity increases with the molecular weight, but not necessarily in a linear way.
What is K value in viscosity?
K value (viscosity), is an empirical parameter closely related to intrinsic viscosity, often defined in slightly different ways in different industries to express viscosity based estimate of statistical molecular mass of polymeric material used particularly for PVC.
How do you calculate decreased viscosity?
Introduction. In the case of neutral polymer solutions, the reduced viscosity ηSP/C is proportional to the concentration C in the dilute solution. This well-known relation is used for determining the intrinsic viscosity [η] simply by extrapolating to C=0.
How to calculate the viscometric constants for chitosan?
Calculation of Mark–Houwink–Sakurada (MHS) equation viscometric constants for chitosan in any solvent–temperature system using experimental reported viscometric constants data Mark–Houwink–Sakurada (MHS) equation constants, a and K, for chitosan in several solvent–temperature systems have been already reported.
How to calculate Mark Houwink Sakurada ( MHS ) equation?
Mark–Houwink–Sakurada (MHS) equation constants, a and K, for chitosan in several solvent–temperature systems have been already reported. In this article, two equations are proposed to determine, a and K, for chitosan in any solvent–temperature system using the previous reported viscometric constants data.
How are the constants of the MHS equation obtained?
The constants were obtained by a deviation in the range of ±0.40–29.0% for the exponent a, and ±6–71% for most of K values. The deviation of experimental and calculation data is reasonable. This is because several factors affecting the correct values for the constants were not taken into consideration by authors whose reported experimental data.