Melt Flow Index MFI

Fig. 23. Correlation between properties (general characteristics), melt flow index (MFI), and mol wt for standard BPA polycarbonate and CD-modified...

Table 2 Melt Stabilizing Efficiency of Antioxidants in PP (processed in an internal mixer at 190°C). Melt flow index (MFI) Measured at 230 C and 2.16 Kg...

However this solution is not always convenient and may prevent high productivity and/or the production of intricate forms which require high temperature processing. Fortunately, some fire retardants dramatically increase the flowability of fire retardant plastics melts. For example ABS, flame retarded with F-2016 or F-2016M (brominated epoxy) has much higher flowability, melt flow index (MFI), and spiral flow index, than virgin ABS (Fig. 1). 

Table 1 Glass transition temperature (7 gi), melting temperature (V m) and melt flow index (MFI) of polymers...

Too little has been published about the flow properties of PET as a criterion for processing. The results of melt flow index (MFI) testing conditions do not correlate with the processing behavior in the case of PET. This may be caused by the discrepancy between the shear rates in testing and processing. MFI is defined as the amount of polymer melt (in g) extruded within 10 min through an orifice of specified diameter at a standard load and temperature. In the case of PET, this method was not very popular until recently due to the sensitivity of this material to hydrolytic degradation. 

Melt flow Index (MFI), melt flow rate (MFR)... 

Another thermal property which is of great industrial importance is the melt viscosity, characterized, e.g., by the melt flow index, MFI, or the melt flow rate, MFR (see Sect. 2.3.4.6). The melt viscosity is first of all influenced by the molecular weight according to ... 

In 83) the authors studied the flow of polypropylene and polyethylene with the help of a constant-velocity viscosimeter developed on the basis of a standard extrusion plastometer for measurement of the melt flow index (MFI) to the stem of which acoustic vibration was applied. 

Modification of BPA-PC for adaptation to the conditions of production of CD and CD-ROM disks, and of substrate disks for WORM and EOD was necessary. BPA-PC standard qualities for extrusion and injection molding have, depending on molecular weight, melt flow indexes (MFI), (according to ISO 1130/ASTM 1238 in g/10 min at 300°C/1.2 kg, between less than 3 g/10 min (viscous types) up to 17 g/10 min. For CDs and optical data storage disks, however, MFI values exceeding 30 g/10 min, and for exceptionally short cycle times (5—7 s) even >60 g/lOmin are demanded at an injection mass temperature of 300°C (see Table 5). 

Fig. 10.48 Numerical simulation results of nonisothermal flow of HDPE, Melt Flow Index MFI = 0.1 melt obeying the Carreau-Yagoda model for a typical FCM model wedge of e/h — 3 and =15. (a) Velocity (b) shear rate and (c) temperature profiles [Reprinted by permission from E. L. Canedo and L. N. Valsamis, Non Newtonian and Non-isothermal Flow between Non-parallel Plate - Applications to Mixer Design, SPE ANTEC Tech. Papers, 36, 164 (1990).]...

Melt Flow Index (MFI) — The amount in grams of a thermoplastic resin flowing through a standard orifice at a specified temperature in 10 minutes. The higher the value, the easier the resin flows in extrusion or injection molding. 

When plastics flow through straight tubes or channels they are sheared and the viscosity expresses their resistance. A method to measure melt flow is by the melt index (MI) [also called melt flow index (MFI)]. It is an inverse measure of viscosity. High MI implies low viscosity and low... 

Sample Polymer Grade Melt flow index (MFI) M. Mw M./M ... 

Similar to that of PTFE, the molecular weight of PFA cannot be measured by conventional techniques. An indirect factor called melt flow rate (MFR), also called melt flow index (MFI), is used, which is defined as the amount of polymer melt that would flow through a capillary rheometer at a given temperature under a defined load (usually, grams in 10 min). It is inversely proportional to viscosity viscosity is directly proportional to molecular weight of the polymer. 

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