| Popis: |
An indirect method of determination of hindered amine light stabilizers (HALS) in polyolefins has been devised based on the quantitative microanalysis of nitrogen in the sample. Two alternative procedures have been tested and found to be suitable for the elemental analysis (hydrogenolysis). In the first, the Raney-nickel catalyst is in contact with the sample and the ammonia formed in the reduction is determined photometrically. In the second procedure the nickel-based catalyst is used as a packing for the reduction tube and the resulting ammonia is titrated. Both procedures are reliable, simple, speedy and universal. None of the common stabilizers, including phosphites and thioesters, interferes with the analysis. No other nitrogen-containing additive should be present, however, otherwise erroneous results are obtained. |
