The calcium content of the recovered PA 6 was measured by dissolving the recovered samples in nitric acid hydrochloride according to DIN EN 13657 (2003-01) and determining the Ca 2+ content via a complexometric method according to DIN 38406-E3 (2002-03). The molecular weight distribution was measured according to DIN EN ISO/IEC 17025 by dissolving the polymer in hexafluoroisopropanol and using a GPC column. The accuracy of the results is estimated to be within 10%.