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Melt Flow Index (MFI)
Melt Flow Rate (MFR)

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ASTM D1238 (Procedure A),
ISO 1133 (Procedure A)

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Melt Flow Rate measures the rate of extrusion of thermoplastics through an orifice at a prescribed temperature and load. It provides a means of measuring flow of a melted material which can be used to differentiate grades as with polyethylene, or determine the extent of degradation of the plastic as a result of molding. Degraded materials would generally flow more as a result of reduced molecular weight, and could exhibit reduced physical properties. Typically, flow rates for a part and the resin it is molded from are determined, then a percentage difference can be calculated. Alternatively, comparisons between "good" parts and "bad" parts may be of value.

Test Procedure:
Approximately 7 grams of the material is loaded into the barrel of the melt flow apparatus, which has been heated to a temperature specified for the material. A weight specified for the material is applied to a plunger and the molten material is forced through the die. A timed extrudate is collected and weighed. Melt flow rate values are calculated in g/10 min.

Specimen size:
At least 14 grams of material is needed.

Flow rate = ( 600/t x weight of extrudate )
t = time of extrudate in seconds
melt flow rate = g/10 min.

Equipment Used:
CSI Melt Flow Indexer (Extrusion Plastometer)

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**Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. For more information please contact a Intertek PTL Technical Representative at . Due to copyright restrictions, we are not able to provide copies of standards. Standards can be obtained from appropriate standards authorities.

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