Polymeric azo initiators

The synthesis and characterization of a series of polymeric initiators as well as their applications in several radical polymerization methods are presented.; One monofunctional and four polyfunctional polymeric initiators have been synthesized. These polymeric initiators showed surface-active properties in aqueous solutions. Both intermolecular and intramolecular micelle formations have been examined. Intermolecular micelle formation was revealed in surface tension and viscosity studies. The CMC values were found to increase as the hydrophilicity of the polyfunctional initiators decreased in contrast to what might be expected in the monomeric surfactant systems. Refractive index measurements on these polymeric initiators in aqueous solutions indicated that three polyfunctional initiators existed as intramolecular micelles in dilute solutions.; By use of these surface-active polymeric initiators, a surfactant-free emulsion polymerization system was developed. Monodisperse polymer particles have been prepared using this polymerization method. The particle size was found to increase as the PEG chain length of the polyfunctional initiators increased and the largest monodisperse particles were obtained in the polymerization using the monofunctional initiator.; The surface-activity of the polymeric initiators was also utilized to establish a stabilizer-free dispersion polymerization. Particles with size up to 17 {dollar}mu{dollar}m have been prepared in this study.; The use of polymeric initiators in surfactant-free inverse emulsion polymerization has been investigated as well. In this study a polyfunctional initiator was partially decomposed in the presence of styrene to give azo-containing prepolymers which were able to stabilize water-in-oil emulsions. These prepolymers were then used as initiators as well as surfactants in the inverse emulsion polymerization of sodium styrenesulfonate. The resulting block copolymers showed polysoap behavior in aqueous solutions. Both intermolecular and intramolecular micelle formations were examined.; The investigation was further extended to prepare ultra-high molecular-weight polymers. By using a novel inverse emulsion polymerization method, polyacrylamide with molecular weight as high as 3 {dollar}times{dollar} 10{dollar}sp7{dollar} g/mole has been obtained in this study.