What is the viscosity of polystyrene?
The viscosity of solutions of polystyrene of various molecular weights (from 1.04 · 102 to 3.8 · 105) in a poor solvent (decalin) and a good solvent (ethylbenzene) has been measured at temperatures from 15 to 70°C over a broad range of shear stresses from 102 to 106 dyne/cm2.
What is viscosity average molar mass?
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. The molecular weight of the polymer solution is very high so the viscosity of polymer solution is very high compared to that of pure solvent.
How do you find the molecular weight of polystyrene?
A polymer’s molecular weight is related to that of the monomer, and the number of monomers present in the polymer molecule. The molecular weight of styrene is 104 Da. Hence, the molecular weight of polystyrene is 104n, where “n” is the styrene molecule number in the polymer chain.
What is the relationship between molar mass and viscosity?
A High molecular weight increases the chemical resistance – to a point. It takes more damage to the main chains of the molecules before it will affect the strength of the material. A High molecular weight increases the viscosity of the material – makes it harder to process the material using conventional methods.
Does viscosity depend on molecular weight?
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 mn for polymers?
Number average molecular weight: Mn is the number of chains of that molecular weight. Mn can be predicted by polymerization mechanisms and is mea- sured by methods that determine the number of molecules in a sample of a given weight; for example, colligative methods such as end-group assay.
What is weight average molecular weight?
2.4. Weight average molecular weight (Mw) measuring system includes the mass of individual chains, which contributes to the overall molecular weight of the polymer. It is based on the fact that bigger molecules contain more mass than smaller molecules.
What is the average molecular weight of polystyrene?
The weight-average molecular weight (Mw) of the commercially-available PS that is widely used as industrial material is generally 150,000 to 400,000.
What is size average molecular weight?
The average molecular weight is determined by summing the weights of all the chains and then dividing by the total number of chains. The average molecular weight is an important method of characterizing polymers. The three ways to represent average molecular weight is: number average molecular weight, M.
What is number average molecular weight of a polymer?
N. The number average molecular weight is defined as the total weight of polymer divided by the total number of molecules.
What is number average?
(Thanks Carl Sagan!!) The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample. To get the number average molecular weight you divide the total weight of the sample by the total number of the molecules.