melt flow rate Polymer test

1. hassan-alnajem
MFI | MFR
By : Hassan ALNAJEM

2. MFI
• The melt flow index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer. It is d
efined as the mass of polymer, in grams, flowing in ten minutes through a capillary of a specific diameter
and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed
temperatures. Polymer processors usually correlate the value of MFI with the polymer grade that they hav
e to choose for different processes, and most often this value is not accompanied by the units, because it
is taken for granted to be g/10min. Similarly, the test conditions of MFI measurement is normally express
ed in kilograms rather than any other units. The method is described in the similar standards ASTM D123
8 and ISO 1133.
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3. MFI
• MFI (In Grams) = Weight of Melted samples in 10 minutes
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4. What do you gain from melt flow testing?
1. A typical index value for verifying in-house material
2. Quality check of entrance materials
3. Comparison of new materials in a product development setting
4. Evaluation tool for new material suppliers
5. Quick comparisons of batches of material
6. Estimation of flow properties for simple extrusion processes
7. Predictions of how a polymer will behave in a number of processing techniques
• Applicable Standards
• ISO 1133
• ASTM D1238
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5. What affects the melt flow properties of polymers ?
Many factors affect polymers' flow properties. Molecular weight distribution, t
he presence of co-monomers, the degree of chain branching and crystallinity in
fluence a polymer's MFI as well as heat transfer in polymer processing.
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6. MFI Parts
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A Melt flow indexer consists following components
1) Barrel
2) Heaters
3) Piston
4) Orifice
5) Weights
Piston
Barrel Cleaning Tool
Packing tool
Die Cleaner
Orifice
Funnel

7. Barrel
1 Barrel
Barrel or cylinder is made up of steel. It is having diameter of 50.8 mm and length of 162 mm. It is having a
smooth and straight hole having dia of 9.5504 ± 0.0076 mm. It is used to heat the pellets by means of heater
and convert it to molten polymer.
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8. Heaters
2 Heaters
Heaters are being used to heat the barrel. It should be precisely controlled by temperature controller. The he
ater should have capacity of heating in the range of ±0.2oC
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9. Piston
3 Piston
Piston is made of steel with insulating bushing at top as a barrier to heat transfer to weights applied on it. Fo
r ASTM Piston dia of the head is 9.4742 ± 0.0076 and length of head is 6.35 ± 0.13 mm. It is also having tw
o reference marks having distance of 4 mm. Piston is having a working length at least as long as the cylinder.
For ISO piston dia of piston head is 6.35±0.10 mm. It is having the distance of two reference mark at the dist
ance of 30 mm. Dia of the piston head shall be less then the internal dia of the cylinder by 0.075± 0.010 mm
.
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10. Orifice
4 Orifice
Orifice is made up of Tungsten carbide. Diameter of orifice should be such that it should fall freely in to bar
rel. Die should have bore dia of 2.0955 ± 0.0051 mm & length of 8.000 ± 0.025 mm. Finishing of the orifice
is critical. It’s bore should be smooth and dent free.
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11. Weights
5 Weights
Weights are used to applied load. They are standard and precise. Commonly 2.16 kg of weight
is used for measurement of Melt Flow Index. In HDPE 5 kg weight will be used for measureme
nt of MFI. Some times 5kg, 10 kg and 21.6 kg weights are also used to measure I5, I10 & I21
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12. hassan-alnajem
Thank you
By : Hassan ALNAJEM
Alnajemhassan@gmail.com