USE OF CROWN-ETHER IN THE ANIONIC-POLYMERIZATION OF PROPYLENE-OXIDE .3. PREPARATION AND MICELLIZATION OF DIBLOCK-COPOLY(OXYPROPYLENE OXYETHYLENE)

Diblock-copoly(oxypropylene/oxyethylene)s with moderately-long P-blocks (about 200 P units) and narrow block-length distributions were prepared by use of 18-crown-6 ether and the potassium salt of methoxypropanol in the sequential anionic polymerization of bulk propylene oxide at room temperature and ethylene oxide at 40-80-degrees-C (melt). The micellization of one of these copolymers, denoted P200E560, was studied by a number of techniques: surface tension, gel permeation chromatography, photon correlation spectroscopy, electron microscopy. The quantities obtained (critical micelle concentration, hydrodynamic radius, micelle size distribution) were compared with published results for other diblock and triblock copolymers.