Melt Flow Index (MFI) | A melt flow analysis method that determines the ease of flow of plastic materials |
Why it’s useful:
Because the melt flow rate depends on molecular weight, additives, and other ingredients, the melt flow index value allows for direct comparison of materials to each other. The melt flow rate values are also used as specification values to allow for the sourcing of raw materials from multiple suppliers. Significantly different MFI values can be used to alert a purchaser that the material has changed compared with previous lots, batches, or suppliers of the plastic. MFI values can also be used to differentiate different grades of material. When used to compare "good" samples with "bad" samples, MFI values can provide insight into material degradation resulting from processing, transportation, storage, and drying conditions. MFI analysis is frequently used as one of the first tests when conducting failure analysis.
Sample Requirements:
A single MFI determination requires about 10 grams of material, and samples are typically evaluated in triplicate. Usually a few trial runs are needed to set the proper mass charge for the tester, so ideally we like to have about 100 grams of sample.
Typically samples are in the form of pellets, sheets, or powders. However, we are capable of custom sample preparation in order to grind unusually shaped products or components into the ideal form. Because we can convert manufactured products into plastic powder, the melt flow analysis can be reliably determined for finished products.
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