The MFI is the weight of polymer melt flowing out from a standard die at a given temperature and with a standard weight applied to the piston. The test conditions of MFI measurement are normally expressed in kilograms. 

MFI stands for Melt Flow Index, a measure of the melt flow properties of thermoplastic polymers ASTM stands for American Society for Testing and Materials, an organization that develops widely used standards, including standards for testing plastics and polymer materials. ASTM stands for American Society for Testing and Materials.

What is the ASTM standard for MFI?

The test method commonly used for melt flow rates in ASTM standards is ASTM D1238, known as "Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer". Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer".) The standard describes the use of an extrusion flow meter to measure the flow properties of a plastic melt through a standard orifice under specified conditions.

The ASTM D1238 standard covers different types of plastic materials such as polyethylene (PE), polypropylene (PP), and polystyrene (PS). Using this standard it is possible to determine the melt flow rate, which is important for the processing and performance of plastics. Different types of plastics may have different melt flow rate requirements depending on their intended use.

It is important to note that the ASTM standard was developed by the American Society for Testing and Materials (ASTM), so other standards or test methods may be used to measure melt flow rates in other countries or regions.