BS ISO 16014-2:2012

1   Scope This part of ISO 16014 specifies a method for determining the average molecular mass and the molecular mass distribution of polymers using size-exclusion chromatography (SEC). The average molecular mass and the molecular mass distribution are calculated using a universal calibration curve instead of the conventional calibration curve. A list of documents related to this part of ISO 16014 is given in the Bibliography.

   NOTE  The concept of the universal calibration method is based on a relationship by which the retention time in SEC depends on the size of the polymer molecule (the hydrodynamic volume) or on the product of the intrinsic viscosity [ η ] and the molecular mass   M  . Many polymers classified as random-coil polymers (regardless of their chemical structure, degree of branching, composition or tacticity) have been experimentally confirmed as following this relationship. The universal calibration curve is prepared by plotting the logarithm of [ η ]  M   against the elution time   t   or elution volume   V   using polymer standards such as polystyrene with narrow molecular mass distributions. The molecular mass   M    i   of an unknown polymer sample can then be calculated from the value of [ η ] M  at each retention time using the universal calibration curve and [ η ] or  <span style="font-family:Times N...