Molecular weight melt flow rate

Table 1. Melt flow rate (MFR), weight and number average molecular weights (M and M ) and molecular weight distribution (MWD) of the PP, PP-CR154, PP-CR402 and PP-CR546...

Fig. 8-6 Melt flow rates as a function of molecular weight distribution.

The viscosity average molecular weight typically falls somewhere between Mn and 5.2.3.3 Melt Flow Rate... 

The rate at which a molten polymer flows through a capillary under standard conditions is known as its melt flow rate (MFR). The melt flow rate of a polymer is inversely related to its molecular weight. Theoretically, a melt flow rate can be converted to a molecular weight, but this is rarely done in practice. Polymer engineers commonly refer to melt flow rates when comparing material specifications and make comparisons directly based on these values. 

What is meant by the term melt flow rate How is it related to molecular weight ... 

Molecular Weight Versus Melt Flow Rate for Bionolle. 289... 

Fig. 4 Melt flow rate (MFR) measured at 190°C and 2.16 kg as a function of molecular weight for linear and LCB Bionelles...

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 ... 

Molecular Weight. The molecular weight of polypropylene is typically determined by viscosity measurements. The melt viscosity, or melt flow rate, measured under standard conditions, can also be correlated... 

TABLE XII Qualitative expression of effects on high density polyethylene of changes in melt flow rate, density, and distribution of molecular weight... 

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. 

Plastics are either truly homogeneous, amorphous solids or heterogeneous, semicrystalline solids. There are no purely crystalline plastics since so-called crystalline materials also contain different amounts of amorphous material semicrystalline is technically more accurate. Various methods of defining and evaluating plastics are used such as their molecular weight distribution (MWD). A narrow MWD enhances the performance of plastic products. MWD effects melt-flow rates. 

---