The PA 6 recovery as a function of the dissolution time is shown in Figure . The repeatability of the experiments is indicated by relative standard deviations often below 3 yield%. We found that the conversion as well as the recovery of PA 6 increased with increased dissolution time which is fully in line with the existing literature . A clear trend is observable which shows a steep initial increase in the PA 6 recovery for short times and a gradual levelling off of the dissolution rate at dissolution times above 4 hours. Experiments with dissolution times of 72 h were also conducted and it was found that both ultrasound and microwaves led to a complete dissolution of PA 6. A dissolution time of 3 h was used in further investigations in this work in order to leave room for improvement when varying other parameters.