Investigation of Novel Living Radical Polymerization

• Main Authors: Yu-Hsiang Hu, 胡毓祥
• Other Authors: Chuh-Yung Chen
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/49729305675873329354

博士 === 國立成功大學 === 化學工程學系碩博士班 === 93 === Abstract Living radical polymerization of vinyl monomer by thiol and lactam as initiator was investigated in this thesis, including the mechanism, reactivity of copolymerization, and thermal degradation behavior. Proton is transferred from thiol to lactam group and forms the inter-medium structure, thiolamide, as the active specie during the initiation step. Propagation reaction, thereby, occurs via monomer insertion from the terminal group of the polymer chain end. Molecular weight can be controlled by the monomer-to-thiol ratio. Lactam in this system acts as a capping agent, which in terms to control the tactility and the dynamic equilibrium of activation/deactivation process. In addition, polymers prepared by this route have high glassy transition temperatures due to the high proportion of syndiotactic conformation produced. Solvent effects were also examined to reveal the evidence of capping agent on the polymerization rate, tactility, and molecular weight distribution. Since the absence of termination reaction in the system, polymers without vinyl-bond are generated, which causes the high thermal stability. For copolymerization, the polymerization rate enhanced by adding a few mole ratio of comonomer bearing with electron withdraw group, meanwhile the reactivity will also vary accordingly. Finally, well-defined block copolymers were successfully synthesized by this novel approach.