BS EN ISO 16014-5:2019 PDF

What is ISO 16014-5 - Determination of average molecular weight with SEC-LS about?

ISO 16014-5 is the fifth part of the multi-series ISO 16014. ISO 16014-5 specifies a general method for determining the average molecular weight and the molecular weight distribution of polymers using SEC-LS, i.e., size-exclusion chromatography coupled with light-scattering detection. The average molecular weight and the molecular weight distribution are calculated from molecular weight data and weight concentrations determined continuously with elution time. The molecular weight at each elution time is determined absolutely by combining a light-scattering detector with a concentration-sensitive detector. Therefore, SEC-LS is classified as an absolute method. method applies to linear homopolymers and nonlinear homopolymers such as branched, star-shaped, comb-like, stereo-regular, and stereo-irregular polymers. It can also be applied to heterophasic copolymers whose molecular composition cannot vary. However, SEC-LS is not applicable to block, graft, or heterophasic copolymers whose molecular composition can vary. And the methods apply to molecular weights ranging from that of the monomer to 3 000 000 but are not intended for samples that contain > 30 % of components having a molecular weight < 1 000.