Melt Flow Index (MFI)
Melt flow index is a measure of how easily a thermoplastic flows under specified temperature and load conditions. It is often used as a practical indicator of viscosity, molecular weight, processing behavior, and grade-to-grade consistency.
See related terms:
Extrusion
Viscosity
Molecular Weight Distribution
Rheology
Thermoplastic
MFI test diagram showing polymer melt flowing through a standard die.