What is K value in viscosity?

What is K value in viscosity?

K-Value. Definition: (1) A number calculated from dilute solution viscosity measurements of a. polymer; sometimes used to indicate likely degree of polymerization/molecular size.

What is Mark Houwink parameters?

Mark–Houwink (MHKS) parameters derived from the SEC/ESI-MS measurements of broad polymer samples synthesized by radical chain transfer polymerization. SEC/ESI-MS allows determination of MHKS parameters only in relation to a reference parameter pair.

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

Mark-Houwink Constants 1

Polymer / Solvent T (°C) K x 103 (ml/g)
Polystyrene (atactic) / Trichlorobenzene 135 14.7
Polystyrene (atactic) / Toluene 25 8.6
Polystyrene (isotactic) / Benzene 30 10.1
Polystyrene (isotactic) / Tetrahydrofuran 25 16.0

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.

How do you calculate the k value?

K-value is defined as the equilibrium ratio of vapor to the liquid mole fraction of a component in a mixture [10]:(1) K i = y i x i where Ki, yi, and xi are respectively, the K-value of component i, vapor phase mole fraction of component i, and liquid phase mole fraction of component i.

What is the value K?

K Value is a steady state of the heat flow through a unit area of a homogeneous material induced by the unit temperature gradient. It is used to describe British thermal unit (BTU) per hour. The K Value is independent of the thickness of a substance. It is expressed as watts per meter-Kelvin.

WHAT IS A in Mark — Houwink equation?

molecular weight. ) and having the form: [η]=K⋅Mar where [η] is the intrinsic. viscosity. , K and a are constants the values of which depend on the nature of the polymer and solvent as well as on temperature and Mr is usually one of the. relative molecular mass.

What is number average molecular weight?

The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample. For example, there are 13 molecules with a weight of 550,000 so the total weight of molecules with a weight of 550,000 is 13 x 550,00 or 7,150,000.

What does polystyrene look like?

Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. As a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature.

How do you do an end group analysis?

Analysis of Polymers using End Groups. Because of the importance of end groups, there have been many analytical techniques developed for the identification of the groups. The three main methods for analyzing the identity of the end group are by NMR, mass spectrometry (MS) or vibrational spectroscopy (IR or Raman).

How do you calculate relative viscosity?

First, measure the pure solvent and then a polymer solution of defined concentration. However, in a range of sufficiently low shear rates, their behavior is Newtonian. Dividing the viscosity of the polymer solution (η) by the viscosity of the pure solvent (ηο) gives the relative viscosity with the dimensionless unit.

How do you calculate decreased viscosity?

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 is the Mark Houwink equation related to viscosity?

Mark-Houwink Equation. is intrinsic viscosity. K is a constant. is a scalar which relates to the “stiffness” of the polymer chains. If in solution, the polymer molecules are rigid rods, then a=2. On the other extreme, if the polymers are hard sphere, a=0. If a=1, the polymers are semicoils.

How does the Mark Houwink and Landau equation work?

The Mark–Houwink equation, also known as the Mark–Houwink–Sakurada equation or the Kuhn–Mark–Houwink–Sakurada equation or the Landau–Kuhn–Mark–Houwink–Sakurada equation gives a relation between intrinsic viscosity and molecular weight : From this equation the molecular weight of a polymer can be determined…

How is the IUPAC Mark Houwink equation written?

Mark–Houwink equation. https://doi.org/10.1351/goldbook.M03706. The equation describing the dependence of the. intrinsic viscosity. of a polymer on its. relative molecular mass. (. molecular weight. ) and having the form: [η] = K ⋅ Ma r where [η] is the intrinsic.

What are the values of Mark-Houwink parameters?

The values of the Mark–Houwink parameters, and , depend on the particular polymer- solvent system. For solvents, a value of is indicative of a theta solvent. A value of is typical for good solvents. For most flexible polymers, . For semi-flexible polymers, . For polymers with an absolute rigid rod, such as Tobacco mosaic virus, .