DIN 55672-3:2016-03

This standard specifies the determination of the molar-mass distribution and the average molar mass values M_n(number average) and M_w(weight average) of polymers that are soluble in water by gel permeation chromatography (GPC). This method is applicable to neutral polymers and polyanions (for example, polycarboxylates, polysaccharides, fully hydrolyzed polyvinyl alcohols and high-molecular polyethylene oxides); it is not applicable to polycations (for example, polyvinylpyrrolidone, polyvinylpyridine, salts of poly(diallyl-N,N-dimethylazacyclopentane), chitosan). Despite good solubility in the mobile phase and even though the chromatograms obtained show good repeatability, it is possible that this method cannot be used with certain polymer types because of specific interactions (for example adsorption) within the sample/eluent/column system. See also Clause 12. The method is not an absolute one and requires calibration with commercially available unbranched pullulan standards that have been characterized by independent absolute methods. The results for samples of polymers with different chemical structures are therefore only comparable within groups of samples of the same type. The conditions specified in this document are not applicable to the GPC analysis of polymer samples with Mw values greater than 106 g/mol and/or polymers with elution limits outside the calibration range (see 7.6 and Annex C). This document includes no correction methods (for example, for the elimination of peak broadening). If absolute molar mass values are required, an absolute method (for example, membrane osmometry for M_n or light scattering for M_w) can be used. The standard DIN 55672-3 has been prepared by Working Group NA 002-00-02-03 AK "Gelpermeationschromatographie" ("Gel permeation chromatography") of Working Committee NA 002-00-02 AA "Lackrohstoffe" ("Raw materials for paints and varnishes") at DIN Standards Committee Coatings and Coating Materials (NAB).