How do you calculate melt flow index?

Test Procedure: 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.

What is MFI value?

The MFI value quoted on many datasheets refers to the amount of polymer that is extruded through a known given orifice (die) and expressed as quantity in g/10 mins or for Melt Volume Rate in cm3 /10mins .

What is melt flow index used for?

1 Melt flow index. MFI is a simple measurement of the quantity of polymer pushed through a die of specified dimensions at a set temperature within 10 min. It is frequently used to compare grades of the same polymer, as it gives an indication of the molecular weight present in that batch or grade.

What is a high melt flow index?

Melt Flow Indexer In general, a higher MFI indicates a lower material viscosity, and when comparing polymers of the same class, a lower melt flow rate corresponds to a higher molecular weight and/or less branching.

What is the MFI of LDPE?

1. LDPE has an MFI of 0.3 ± 0.05 g/10 min; however, PLA has an MFI of 5.9 ± 0.08 g/10 min which are very close to values found for non-extruded pellets. This measurement was undertaken to check any degradation of polymers when being extruded.

How do you increase MFI of polypropylene?

You can increase MFI by mixing with some lubricant. However it may reduce mechanical properties. So it would be better to conduct a small scale experiment in advance to know the optimum amount of lubricant you should add.

What is the melt flow index of pet?

The value of the intrinsic viscosity for the PET resin is very important and analogous to the Melt Flow Index (MFI). In general, bottles made from PET have an intrinsic viscosity value IV of about 0.8 dl / g. Otherwise, food trays have a measurement of about 0.6 dl / g.

Can you determine viscosity from MFI?

One should be aware that even though MFI is the dominate method used to characterize how plastic will flow in a mold, it does not actually provide a measure of viscosity. Melt Flow Index (MFI) is a measure of how many grams of a polymer flow through the die in ten minutes.

How can I increase my MFI?

What is the melt flow rate of polypropylene?

The polypropylene used in this research is grade EH-102 of the company “PETKIM.” The most important reason for choosing this material is that its melt flow index (9.0–13.0 g/10 min) is high and it is possible to use this material in combination with relatively high filler contents.

What is the relation between MFI value and viscosity?

MFI values are meant to be inversely proportional to the viscosity of the plastic at the given conditions of the test. The higher the MFI value, the lower the viscosity is supposed to be.

How do you use melt flow index?

Melt Flow Index (MFI) is a measure of how many grams of a polymer flow through the die in ten minutes. The test is performed at a given temperature depending on the plastic. The force used to push the plastic through the system is supplied by a weight which sits on top of a ram.

How is melt flow index related to viscosity of plastic?

The Melt flow index is an indirect measure of the viscosity of thermoplastics. The higher the melt flow index, the lower the viscosity of the melted plastic. The Melt flow indexer is a quick method to measure the flow properties of plastics and is often used to assess batch-to-batch variations.

How is the melt flow rate related to the melt index?

The melt flow rate is an indirect measure of molecular weight, with high melt flow rate corresponding to low molecular weight. Synonyms of MFI are melt flow rate and melt index, which are commonly abbreviated: MFR and MI. When the volume of the extrudate is measured, the melt volume rate is reported. Table 3.14.

What should the melt flow index be for polypropylene?

For example, to extrude polyethylene with wood flour, an MFI as low as 0.3–1 g/10 min (190 °C) may be used, for polypropylene MFI values of 2–12 g/10 min (230 °C) may be used; however, for injection moulding PP, a much higher MFI of 30–70 g/10 min may be needed, to allow for some reduction in MFI on fibre addition, but maintain good mould filling.

When do you use a melt flow indexeris?

The melt flow indexeris the most popular device in the plastic industry to determine material viscosities and is often used to test batch-to-batch consistency. However, it is also the least accurate method. To obtain more accurate and meaningful viscosity data, a capillary or a cone and plate rheometer should be used.