Mixture of two or more fractions of the same polymer, each of which has a different molar-mass distribution.
Source:
PAC, 2004, 76, 1985. 'Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)' on page 1988 (https://doi.org/10.1351/pac200476111985)