NUCLEATION KINETICS OF EPSILON-CAPROLACTAM MELTS IN THE PRESENCE OF WATER IMPURITY

The nucleation of E-caprolactam in melts containing water impurities b etween 3% and 7% w/w was investigatedin a batch reactor monitoring mel t temperature. The induction times preceding the formation of epsilon- caprolactam nuclei were inversely proportional to the melt supersatura tion and a threshold in the supersaturation of about 6% was found for homogenous nucleation. The interfacial tensions calculated using the c lassical nucleation theory ranged between 0.8 and 1.5 mJ m(-2) for wat er content of 3%-7%, respectively. The concomitant increase of the siz e of the critical nucleus suggested that water inhibits the process of nucleation of epsilon-caprolactam in melts containing water impurity, This conclusion was further confirmed for the rates of crystal growth of the epsilon-caprolactam in the melts measured from the rates of te mperature increase with time.