The cyclic dimer 1,8-diazacyclotetradecane-2,9-dione is one of the most important components of caprolactam solution concentrates and triggers significant agglomeration during the recovery process in industrial polyamide-6 plants. For this reason, the agglomeration behaviour and morphology changes of cyclic dimers in solution concentrates were investigated. Precipitates separated from an similar to 80 wt.% solution concentrate were explored. Cyclic dimers aggregated in the solution concentrates at lower temperatures to form larger, thicker, and compacted structures or multi-layers structures. ...
