Thermal Analysis
Melt Flow Index (MFI)
The Melt Flow Index is a measure of the ease of flow of the melt of a thermoplastic polymer. It is defined as the mass of polymer in grams flowing in 10 minutes through a capillary of specific diameter and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed temperatures. The method is given in ASTM D1238 and ISO 1133 (similar).
The melt flow rate is an indirect measure of molecular weight, high melt flow rate corresponding to low molecular weight.
Synonyms of Melt Flow Index are Melt Flow Rate and Melt Index. Actually, more commonly used are their abbreviations: MFI, MFR and MI.
Applications:
- Common QC Test
- Measurement of molecular weight degradation
- Comparison of processability of compounded thermoplastic polymers
- Classification of grades of raw thermoplastics