Dispersity in polymer science (IUPAC Recommendation 2009)

Abstract This recommendation defines just three terms, viz., 1. molar‐mass dispersity, relative‐molecular‐mass dispersity, or molecular‐weight dispersity, 2. degree‐of‐polymerization dispersity, and 3. dispersity. “Dispersity” is a new word, coined to replace the misleading, but widely used term “polydispersity index” for M̄w/M̄n and X̄w/X̄n. The document, although brief, also has a broader significance in that it seeks to put the terminology describing dispersions of distributions of properties of polymeric (and non‐polymeric) materials on an unambiguous and justifiable footing. Copyright © 2009 Society of Chemical Industry