| Research Abstract |
To establish a novel concept, "latent catalyst" of "latent initiator", which initiate and control the polymerization by an appropriate stimulation, syntheses of various novel latent initiators, establishment of the principle for the design of latent initiators, and application of latent initiators for the novel polymerization system have been studied. It was clarified that various types of pyridinium salts, sulfonium salts, and phophonium salts serve as excellent thermal-and/or photo-latent initiators in the polymerization of various cationically polymerizable monomers such as epoxides, stirenes, and vinyl ethers. After the study on the relationship among the structure, catalytic activity, and threshold temperature or wave length above which the latent initator serve catalytic activity, not only the principle for the molecular design of the latent catalyst which serve catalytic activity at desired temperature or wave length, but the concept of thermal and photo-latent initiator for the cationic polymerization was established. Further, it was clarified that phthalimides, malononitriles, sulfonic acid esters, and carboxylic esters also serve as salt-free thermal-latent initiators for the cationic polymerization. Novel conceptual materials such as novel polymers which show no shrinkage on the curing by self-catalyst, novel catalysts for the acetalization, and photo-curable common polymers have been developed. It was clarified that not only initiation step but also elongation step can be controlled by the latent initiators using the nuclephiles released on the initiation step. Novel conceptual polymerization system such as novel living polymerization system which can be isolated and stable in the air and selective polymerization of bifunctional monomers without crosslinking have been developed. Novel latent initiator system by which polymerization can be control by any optional stimulation may be developed by the application of the concept of the latent initiators for
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