Melt mass-flow rate

ISO 11357 2005 Plastics - Determination of the melt mass-flow rate (MFR) and the melt-volume flow rate (MVR) of thermoplastics. International Organization for Standardization, Geneva, Switzerland. 

Scale-up of gas atomizers is difficult and it requires the use of higher gas-to-melt mass flow rate ratio to maintain the same droplet size. The scale-up may also cause some complex phenomena to occur, such as the disappearance of the prefilming effect in close-coupled atomizers, the generation of turbulence in melt flow within delivery nozzle, and change in atomization mechanisms. 

Melt Mass-Flow Rate (MFR) 9.2 g/lOmin ASTM D1238... 

ISO 4440-2 1994 Thermoplastics pipes and fittings - determination of melt mass-flow rate... 

Melt mass-flow rate Melt volume-flow rate ISO 1133 Molding compound g/lOmin cmtylO min At test conditions for temperature and load specified in Part 2 of appropriate material standards. 

Plastics—Determination of the Melt Mass-Flow Rate and the Melt Volume-Flow Rate of Thermoplastics... 

Melt mass flow rate ASTM D1238 kg.s Ib./h... 

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-... 

Small differences in crystallinity affect the density. For an exact and reproducible density determination the specimen must be eonditioned and the history of the specimen preparation must be known. Density is often measured together with the melt mass-flow rate and both serve as characteristic material parameters. Therefore, preparation and conditioning method based on the ASTM D2839-87 Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene has proved suitable The density is determined on extrudates fi om the melt mass-flow rate measurement after boiling in water for one hour. 

The measurement of melt mass-flow rate and density is usually the first step in the specification and identification of polyethylene materials. It should be noted that the density of the base polymer differs from the density of the finished geomembrane mixed with carbon black. The confusion, which can occur in the classification of the PE resin, has briefly been dealt with in Sect. 2.1. As a rule, only geomembianes coloured black by carbon black, and not their natural-coloured resin, reach a density which properly meets the classification of HOPE plastic material (see Sect. 2, Tables 2.2 and 2.3). However, one may not consider these classification limits as strict technical criteria even if the density of the black geomembianes is just below 0.940 g/cm, it may correspond to what is ealled HOPE geomembrane over the whole spectrum of its characteristics. 

Table 3.4. Code numbers of melt mass-flow rate ranges and test eonditions according to EN ISO 1872-1...

Tensile test, measurement of melt mass-flow rate (MFR) and density, see Sects. 3.2.4 and 3.2.8... 

The behaviour of the mechanical properties of sample 82 is quite unique (Fig. 5.30). The decline in OIT of this sample is accompanied by a continuous decline of its mechanical strength and of the melt mass-flow rate over several years. However, the elongation at break is still far above the yield point (see Fig. 5.24 for the stress-strain curves). The MFR (190/5) and MFR (190/21.6) decreased from 1.4g/10min and 27 g/lOmin (initial values) to 0.9g/10min and 25g/10min (at 982 d) and then increased to 1.5 g/lOmin and 37 g/lOmin (at 2147 d) (Table 5.6). After about 6 years test time the OIT value has dropped below the detection limit both at... 

Melt mass-flow rate MFR of resin, MFR of geomembrane IMFR I < 15 %, ImFR I absolute value of difference in MFR between resin and geomembrane DIN ISO 1133... 

Tensile elongation (%) Tensile modulus (MPa) Tensile strength (MPa) Melt mass flow rate Melting (g/10 min) point (°C) Heat deflection temperature (°c)... 

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. 

Fig. 18.8 Liquid sheet breakup (left) characterization of sheet breakup length by positions of perforation- and droplet formation (right) liquid sheet breakup length vs. melt mass flow rate, experimental data from Achelis et al. [13]...

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