molecular number-average Mn

The molecular number-average (Mn) is a measure of the average molecular weight of a polymer in a given sample. It is calculated by summing the product of each molecular weight and its corresponding number fraction, and then dividing by the total number fraction in the sample.

Mathematically, the molecular number-average (Mn) can be expressed as:

Mn = (Σ(Mw * Nw)) / ΣNw

Where: Mn = molecular number-average Mw = molecular weight of each polymer chain Nw = number fraction of each polymer chain

The molecular number-average provides information about the size distribution of polymer chains in a sample and is commonly used in polymer characterization and analysis.