Melt Flow Index

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During the processing of thermoplastic by injection molding or extrusion one of the most important characteristics of the material is the melt flow index of polymer. The possibility of its processing one way or another depends on this value. The melt flow index (MFI) - is the conventional value characterizing the behavior of a thermoplastic polymer in the viscous-flow state during processing it into products. Melt Flow Index (MFI) refers to the grams per 10 minutes pushed out of a die of prescribed dimensions according to an ASTM Standard [1] under the action of a specified load as shown in Figure 1.
The value of the melt flow index of the polymer melt determines the optimal processing conditions - temperature, screw speed, injection pressure
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Experiment procedure

3.1. Composition production Polymer composites based on the EBC and vesuviane have been prepared with the hot rolling through rollers, a result of which at 175-180 °C has been obtained filled polymer composites. The filler content has been varied from 5 to 15 wt.%.

3.2. Melt flow index measurement Determination of melt flow properties were carried out on the Melt Flow Tester, CEAST MF 50 (Instron, Italy). MFI test was done according to ASTM D 1238. ASTM D1238 defines the method to measure the rate of extrusion of molten thermoplastics using a Melt Flow Tester. The experiment was carried out at 190-250°C. The load was 5.00 kg and the die dimensions are D = 2.095 mm and L = 8 mm. MFI values were calculated using formulation
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Unit for MFI is g/10min. The results of the measurement are shown in Figure 2.

4. RESULTS AND DISCUSSION It is known that the introduction of mineral fillers, usually leads to deterioration of polymer melt flow, due to the sharp increase in the melt viscosity of the composites. However, in this case the introduction of vesuviane not only does not contribute to the deterioration of fluidity, but on the contrary, despite the generally accepted ideas, there is a marked improvement in the rheological characteristics of composites. The influence of the quantity of mineral filler on the melt flow index of EBC has been studied. In Figure 2 have been shown the changes in melt flow index of original EBC and composites filled with vesuviane in concentrations of 5, 10 and 15 wt.% in temperatures 190-250 ° C.

Figure 2. Changes in MFI of filled ethylene-1-butene copolymer As seen in Figure 2, the addition of mineral filler increases the MFI of obtained

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