What is Mark Houwink parameters?

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 K in Mark Houwink equation?

is intrinsic viscosity. K is a constant. With known values for and K it is easy to take the values from an intrinsic viscosity experiment and calculate .

What is the value of K and alpha for polystyrene is?

Mark-Houwink Constants 1

How is molecular weight of polymer determined by viscosity method?

Viscometry or viscosity method was one of the first methods used for determining the MW of polymers. In this method, the viscosity of polymer solution is measured, and the simplest method used is capillary viscometry by using the Ubbelohde U-tube viscometer.

What is Mark Hawick equation?

Mark–Houwink equation. The Mark–Houwink equation gives a relation between intrinsic viscosity [η] and molecular weight M: [η] = KM. From this equation the molecular weight of a polymer can be determined from data on the intrinsic viscosity and vice versa.

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 viscosity of PVA?

50, K = 300 × 10−3 ml/g [11], the viscosity-average molecular weight of the PVA sample was evaluated as 181 970 g/mol.

What are Huggins and Kraemer constant for polymer viscosity?

Huggins’ constant, k′, and Kraemer’s, k′′, are related by: k′ − k′′ = 0.5. Thus, since k′ is often between 0.6 and 0.8, k′′ will often lie between 0.1 and 0.3. (Kamide K, Dobashi T (2000) Physical chemistry of polymer solutions. Elsevier, New York; Huggins ML (1958) Physical chemistry of high polymers.

What is Huggins rule?

The Huggins Equation is an empirical equation used to relate the reduced viscosity of a dilute polymer solution to the concentration of the polymer in solution. It is named after Maurice L.

What is hydrolyzed PVA?

Polyvinyl alcohols (PVA, PVOH) are water-soluble resin of low toxicity. The water solubility primarily depends upon degree of hydrolysis of polyvinyl acetate. 87-89% hydrolyzed product have high degree of solubility, even in cold water, but for the complete dissolution heating to 85°C is required.

How can PVA reduce viscosity?

You can increase the temperature of the processing. In this way the viscosity and the surface tension will be simultaneously decreased.

What is the difference between MN and MW?

Mn is the number averaged MW, and Mw is the weight averaged MW. The midpoint of the distribution in terms of the number of molecules is Mw. The third moment, Mz, has more weighting with regards to higher MWs. The Mw:Mn ratio is termed as polydispersity, and is used for describing the distribution width.

What is MW polymer?

Polymer molecular weight (MW) is the molecular mass of a polymer chain. While small molecules of the same elemental composition all exhibit the same molecular weight, polymer chains exhibit different characteristics.

What is Kraemer equation?

For dilute polymer solutions, an equation relating the inherent viscosity to intrinsic viscosity and concentration. It is. \eta _{inh} = (\ln \eta _r )/c = \left[ \eta \right] + k^{\prime\prime} \left[ \eta \right]^{\rm 2} \cdot c.

How do you make polyvinyl alcohol solution?

To prepare the PVA solution, 4 g of PVA were added to 100 ml distillated water. The mixture was heated and stirred vigorously until all the PVA was dissolved in the water. This took about half an hour. Peptisation was done by addition of 5 ml 1M HNO3 to the solution.

What is the difference between polyvinyl acetate and polyvinyl alcohol?

Polyvinyl acetate is a polymer material having the chemical formula C4H6O2)n. The key difference between polyvinyl alcohol and polyvinyl acetate is that the side chain of polyvinyl alcohol is a hydroxyl functional group whereas the side chain of polyvinyl acetate is an acetate functional group.

How do you make a PVA solution?

Directions for Making a Polyvinyl Alcohol Solution: Slowly sprinkle 80 g of PVA powder into the hot water with vigorous magnetic stirring. Add slowly so as to avoid clumping of the material. Cover the beaker with plastic wrap and continue heating at60-80o C for 4-6 hours or until solution clears. Do not exceed 80o C.

Where can I find Mw from MN?

To calculate the number average molecular weight (Mn), we take the sum of the weight of all the members of each team and divide it by the number of players on that team.

What is Mw polymer?

What is the Mark-Houwink constant?

The Mark-Houwink “ a ” constant is close to 0.75 or higher for these “good” solvents. In a “poor” solvent, which shows a positive heat of mixing; segments of a polymer molecule attract each other in solution more strongly than they attract the surrounding solvent molecules.

What is Mark-Houwink and why is it important in polymer industry?

In the polymer industry, polysaccharides and proteins must circulate through pipes during transport processes where pumps have a very high-energy expenditure and where temperatures must be greatly increased, and at this point calculation of the Mark-Houwink parameters becomes important.

What are the Mark-Houwink parameters used in the measurement of xanthan salts?

Mark-Houwink parameters used are “k” = 2.79 x 10-3 cm 3 /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. Macromolecules 1989; 22: 1863-1865).

How do you calculate Mark-Houwink parameters?

The calculation of Mark-Houwink (M-H) parameters is carried out by the graphic representation of the following equation: where k and a are M-H constants, and with these constants depending upon the type of polymer, the solvent, and the temperature of viscometric determinations.