Viscosity detectors branching distribution

With the intrinsic viscosity distributions obtained from either a viscometer or light scattering detector, previous studies have attempted to quantitatively determine the amount of long-chain branching. First, g was related to g using an assumed value of s, and the appropriate equation from Table 1 was used to calculate the number of branches per molecule. However, because of the assumptions involved, it is more... 

When an on-line viscometer is used together with the refractive index detector to generate the intrinsic viscosity [t]] in order to build the universal calibration curve. Sec. II.B, the intrinsic viscosity [t]] can also be used to determine the presence and degree of branching. This is done by plotting the log of [t]] versus log molecular-weight for each slice of the distribution. This plot is called the viscosity law plot, or the Mark-Houwink plot. It is described by the equation... 

Another recent improvement in detectors is an online viscometery detector. Using the pressure drop across a small capillary and the output of an in-series concentration detector, intrinsic viscosities can be calculated as a fimction of elution volume. These measurements allow viscosity-average molecular weights to be calculated for each elution volume and the construction of a molecular weight distribution. This detector also may be used to characterize branching. 

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