R. Deckwer, I. Kühn, K. Tauer
The nucleation during a heterophase polymerization occurs via an aggregation of oligomers formed in the dispersion medium. The formation of the particle phase takes place if a critical supersaturation is reached. This mechanism is called "aggregative nucleation" and was estabilished in the PhD thesis of I. Kühn.
Aggregative Nucleation The "aggregative nucleation" mechanism was verified by experimental investigations of the very early stages of an styrene emulsion polymerization. A combination of on-line conductivity and turbidity measurements allowed us for the first time the detection of the onset of particle nucleation.
Current activities are concentrated on the preparation and investigation of model oligomers. The phase transition (nucleation) in solutions of these oligomers will be investigated.
The development of nucleation models for heterophase polymeriaztions based on the classical nucleation theory is in progress as well.