Melt flow index or MFI is defined as a measure of the ease of flow of the melt of a thermoplastic polymer and the melt flow rate indicates the ability of the material’s melt to flow under pressure.
This parameter is often used to assess the molecular weight of the test substance since a high melt flow rate corresponds to low molecular weight and vice versa.
Melt Flow Index of any material is defined as the mass of polymer (in grams), flowing through a capillary of a specified length & diameter in a specified time duration (of 10 minutes), when a specific pressure is applied via prescribed alternative gravimetric weights under a prescribed temperature and piston position.
Melt flow rate is a widely used for evaluation of the flow properties of molten plastics polyolefin, polyethylene and polypropylene, besides resins. It is a standard test method used as an indirect measure of the molecular weight and viscosity of the sample under test.
MFI Tester.
A small amount of the sample (around 4 to 5 grams) is made to pass through the melt flow rate. The instrument consists of a small die, with a diameter of around 2 mm. The material is packed properly inside the barrel in order to avoid formation of air pockets.
Then, a piston, which acts as the medium that causes extrusion of the molten polymer, is introduced. After preheating the sample for a specified amount of time, a specified standard weight is introduced onto the piston. Due to the weight exerted by the piston onto the molten polymer, a force is exerted.
This force immediately causes the molten material to start flowing through the die. After this happens for a specified period, a sample of the melt is taken and weighed accurately. The MFI is expressed as grams of polymer/10 minutes of total time of the test.
MFI Tester incorporates special features such a PID microprocessor based temperature controller with a temperature range from ambient to 400 C having a resolution of 0.1 C. It has an accuracy of + 0.1C and is thus a highly reliable and accurate instrument. It is also fitted with a digital pre-settable timer which has range of 59 minutes 59 seconds and a buzzer. The rigid metallic base ensures stability and minimizes vibration during operation.
The standard conditions of temperature, load and piston position are accurately maintained strictly as per ASTM Standards and the equipment strictly complies with ASTM Standard 1238-1992. Further, the equipment comes complete with all standard accessories such as piston, orifice, spanner, spoon, plumb line, funnel, material charger, mirror, orifice cleaner, tweezers, barrel cleaner, sample cutter and accessory stand. A Conformance Certificate, Electric Wiring Diagram, Instruction Manual and Calibration Certificate traceable to NABL approved labs are provided along with the equipment. For more product information visit- Melt Flow Index Tester.