\(M_{i}\) – Molar mass of the chain
\(n_{i}\) – Number of molecules with mass \(M_{i}\)
Another important property is the dispersity that indicates the
relationship between \(M_{n}\) and \(M_{w}\). The more varied the sizes
of the molecules, the greater is the dispersity value (which is always
greater than 1). In the other hand, when chain sizes are close, the
polydispersity is approximately 1.