Pure and Applied Chemistry

Abstract: Most producers of polyamide have their own characterization method to study the rheological properties of polyamide 6 (PA6). However, the measured rheological properties depend strongly on the sample preparation method, humidity regulation, and time-temperature history during the measurement and not least on the kind of rheometer being used. This investigation is the result of an IUPAC project initiated by the Subcommittee on Structure and Properties of Commercial Polymers. Members of several industrial organizations, universities, and institutes cooperated, with the aim of formulating a guideline to measure reproducible rheological properties of PA6. The results of the investigation show the changes in molecular weight during different kinds of rheological measurements due to hydrolysis and amidization reactions. A guideline is introduced which can be used to make comparable rheological measurements on PA6.