Title: melt flow index
Long Title: IUPAC Gold Book - melt flow index
DOI: 10.1351/goldbook.12787
Status: current

Definition
Mass of a polymer in grams that flows through a calibrated orifice at constant temperature under a specified load over a \(\pu{10\!{-}min}\) period.

Notes
1) There is no suitable SI unit for MFI.
2) Specified loads are mandated for specific polymers.
3) The values of MFI as a function of load can give information on the molar mass distribution.
4) Standard procedures for determining MFI are available from ISO and ASTM.

Source
- PAC, 2013, 85, 1017. 'Glossary of terms relating to thermal and thermomechanical properties of polymers (IUPAC Recommendations 2013)' on page 1033 (https://doi.org/10.1351/PAC-REC-12-03-02)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/12787/html
- json: https://goldbook.iupac.org/terms/view/12787/json
- xml: https://goldbook.iupac.org/terms/view/12787/xml

Citation: Citation: 'melt flow index' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.12787
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Accessed: 2026-06-12T21:57:05+00:00