How do you interpret a melt flow index?

Melt Flow Indexer Melt flow indices are often listed on data sheets of thermoplastic materials. 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 does a higher melt flow index mean?

The melt flow index only tests the material at one shear stress, and temperature. In general, a higher melt flow index indicates a lower material viscosity. This means that a material with a melt flow index of 20 flows easier than a material with a melt flow index of 5.

What is the relationship between melt index and molecular weight?

The higher the melt index of the material the lower the average molecular weight of the polymer. If you ask a processor what type of PE they are running, a typical response will be, “I’m running a 7-melt, 953 material.” Translation: a material with a nominal melt index of 7 g/10 min. and a density of 0.953 grams/cm3.

What is the meaning of melt flow index?

The melt flow index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer. It is defined as the weight of polymer in grams flowing in 10 min through a die of specific diameter and length by a pressure applied by a given weight at a given temperature.

How do you increase melt flow index?

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.

How is MFI value calculated?

3.1 MFI Determination The temperature for the MFI calculation is taken 230°C and the standard weight is taken as the 3.2 kg. MFI of the material is calculated as the mass of the material in grams flowing per 10 min.

What is the relationship between melt index 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.

What is the purpose of melt flow index?

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 melt flow index and its unit?

The Melt Flow Index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer. Similarly, the test conditions of MFI measurement is normally expressed in kilograms rather than any other units.

What does melt flow index stand for?

Melt flow index. The melt flow index (MFI) 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 ten minutes through a capillary of a specific diameter and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed temperatures.

How does melt flow index tester work?

The Melt Flow Index Tester comprises of a piston assembly and a heated barrel to store the sample of the resins. The specific amount of load is applied to the piston of the instrument with the help of the weights that are provided with the instrument, and the melted plastic is extruded through a capillary tube.

What is melt flow index tester?

The Melt Flow Indexer, often abbreviated as “MFI”, is an affordable-price tabletop instrument used to test the melt flow resistance (MFR) of a wide range of thermo-plastic materials. The tester conforms to all National and International melt flow resistance standards, including BS EN ISO 1133 and ASTM D1238.

What is plastic melt flow index?

Melt Flow Index. The melt flow index (MFI) or melt flow rate (MFR) is a measure for the ease of flow of melted plastics. It is often used in the plastic industry for quality control of thermoplastics. The method is described in the standards ASTM D1238 and ISO 1133.