Melt-volume index

MPT microceUular plastics technology MVI melt-volume index... 

Volumenbruch) volume fraction Volumenflieftindex melt volume index (MVI), melt volume rate Voluminositat (Bausch) text bulkiness Vorarbeiten preparatory work Vorbehandiung pretreatment, preparation... 

Melt Volume Index n The volume of plastic extruded in 10 min at a given load on a specified die. 

Figure 9.30. Melt flow index vs. weight fraction of calcium carbonate in PP. [Adapted, by permission, from Johnson K C. Antec 96. Volume III. Conference proceedings, Indianapolis, 5th-10th May 1996, 3545-9.]...

However, for boards in Table 4.19, because of a complex interplay between amount (per weight and per volume) of plastic, fly ash, and other ingredients, melt flow index does not change monotonously (Table 4.26). 

High-density flame-retardants enhance the density of the polymer, resulting in a higher melt flow index (referring to the mass of melt that out-flows for 10 min) unless it is measured on a volume basis. 

In addition, the volume of the polymer melt discharged through the nozzle per time interval can also be calculated from the piston movement. This test quantity, with a unit of cmVlO min, is called melt volume-flow rate. Usually, the abbreviation MFR is used for the test quantity of melt mass-flow rate and MVR for the melt volume-flow rate. However, the old abbreviation, MFI (melt flow index) is also often used. Another parameter is the ratio of MFR measured with a large test weight to that measured with a small test weight. This quantity designated as melt flow ratio is unfortu-... 

MFI(r. ) Melt flow index of the multi-component system at temperature T and containing volume fraction of the dispersed phase g/IOmin (6.12)... 

The altered free-volume state of the multicomponent system (polyblend or filled polymer) could be denoted by f(T, < )2), where dispersed polymer phase in case of polyblend and the dispersed filler phase in the case of filled polymer. The melt fiow index of the multicomponent system is denoted as MFI(r, ( >2) and Eq. (8.81) would show the relationship between melt fiow index and the altered free volume. 

The melt index MFR (melt-mass flow rate (g/10 min)) or MVR (melt volume flow rate [cm VlO min]) is measured using a capillary rheometer according to ISO 1133 [170]. The material is melted in a heated cylinder and extruded by a piston under defined pressure through a nozzle into open space. The mass (MFR) or volume (MVR) of extrudate is measured as a function of time. 

MVR Melt-volume flow rate (melt index)... 

Figure 9.65 Variation of tear strength with melt flow index showing the tough-brittle transition for LDPE, HDPE, and EV copolymers at 10% volume fraction of silica. (From Ref. 61.)...

DMPPO—polystyrene blends, because of the inherent flame resistance of the DMPPO component (oxygen index ca 29.5), can be made flame retardant without the use of halogenated additives that tend to lower impact strength and melt stabiUty in other polymers. Approximately one-half of total Noryl sales volume is in flame-retarded grades, ie, VO or VI in a 1.6-mm section (UL-94). 

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