Molecular Mass of Polymers

The properties of polymers are largely dependent on their size, molecular mass and structure. There are different methods to find out the molecular mass of polymers.

What is Molecular Weight Distribution or Molecular Weight Distribution?

Molecular Weight Distribution (also known as Molar Mass Distribution) explains the relationship between the number of moles of each polymer species and molar mass of that species.
 

What is a good Polydispersity Index?

Dispersity describes the variation in the size of the molecules or particles in a mixture. Like that Polydispersity Index refers to non-uniformity in the size of the molecules or particles in a mixture. Its value ranges from 0 to 1. A good polydispersity index is that material whole value lies between 0 and 1. It measures the distribution of molecular mass in each polymer sample.

Definition of Number average molecular weight

It is defined as the statistical average molecular weight of all the polymer chains that are present in a polymer sample. 

   

M_i is the molecular weight of a chain. N_i is the number of chains.

Number Average Molecular Mass

It is the average of the molecular mass of the individual polymers.
 

Polymer Molecular Weight Units

The unit of molecular weight of polymer is either kg/mol or g/mol.
 

Z Average  Molecular Weight

Z average molecular weight or Z average molar mass is the third power average molar mass. It is given by the formula:

Here, M_z represents the Z average molecular weight. M_i is the molecular weight of a chain. N_i is the number of chains.
 

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