Relative molar mass weight average

The relative number- and weight-average molar masses (Mn,sEC and Mw.sec) and the absolute number- and weight-average molar masses (Mw.malls and... 

Gelation occurs at relatively low conversions of monomer to polymer hence the number-average molar mass at the gel point is low. By contrast, however, the weight-average molar mass becomes infinite at the gel point. 

Furthermore, polymeric samples are usually a mixture of macromolecular chains terminated by different end-groups and thus, an interesting quantity to be determined (in order to characterize the mixture) is the relative abundance of end-groups [1—3]. Other two important quantities are Mn and Mw, the number-average and the weight-average molar masses [1—3]. 

In static LLS [43], the angular dependence of the excess absolute time-averaged scattering intensity, known as the Rayleigh ratio Rw(< )> is measured. For a dilute solution measured at a relatively small angle (6), Rw(q) can be related to the weight average molar mass (Mw), the root mean square... 

A naturally occurring sample will usually be a mixture of different isotopes. The quoted molar mass of an element is the average mass (weighted by the relative amount of each isotope present) of an atom in a naturally occurring sample of the element. 

As agreed by the IUPAC Commission on Atomic Weights and Isotopic Abundances in 1979 [42] the relative atomic mass (atomic weight) of an element, E, can be defined for any specified sample. It is the average mass of its atoms in the sample divided by the unified atomic mass unit1 or alternatively the molar mass of its atoms divided by the standard molar mass M = Lmu = 1 gmol-1 ... 

Correlation of weight-average molar mass and relative extent of reaction for trifunctionally branched polyurethanes. Data from M. Adam et at., J. Phys. France 1809(1987). 

Viscosity studies of dilute solutions provide a convenient relative measure of the molar mass and the resultant average, M will lie closer to than to M . The behaviour of polymer melts will be discussed in detail later, but it is noted that the melt viscosity is a strong function of the weight-average molar mass since the parameter m in the relation... 

Molecular weight (AQ - The ratio of the average mass per molecule or specified entity of a substance to 1/12 of the mass of nuclide C. Also called relative molar (or molecular) mass. [1]... 

The dimensionless quantity relative molecular mass (molecular weight), defined as the average mass of the molecule divided by one twelfth the mass of an atom of the nuclide c, is often used in polymer chemistry and called the molecular weight. In this book, the quantity molar mass is also used and the appropriate SI units are given. 

The phrase typical length of chain was used above because, unlike those of other chemical compounds, the molecules of polymers are not all identical. There is a distribution of relative molecular masses Mf) often called molecular weights) and the corresponding molar masses, M. This topic is considered further in section 3.2. The value of Mr for the chain considered in the previous paragraph would be 280 000, corresponding to M = 280 000 g mol. Commercial polymers often have average values of M between about 100000 and 1000000 g moP, although lower values are not infrequent. 

---