Melt Flow Index

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

However it is not always possible to use these catalysts - organic peroxides (with peroxide can be increased MFI of polypropylene almost up to 100 times), and they are not available for all manufacturers. In addition, some additional factors, such as volatility, instability, commercial form can restrict the use of peroxides for the controlled increase in the flow. Modern science has leaped forward and now can not only achieve increase of MFI in the synthesis, but also in the processing. Modifiers have been designed, which change the fluidity of the polyolefins, reduce the viscosity and increase the MFI.

2. Materials

2.1. Filler As mineral filler has been used vesuviane from Gadabay fields of Azerbaijan. Vesuviane, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuviane occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism [5]. The chemical formula for vesuviane is:

Са10 (Мg, Fe)2Al4[SiO4]5∙ [Si2O7]2(OH)4.

2.2. Polymer

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