I.Polyhomologation. Application for the synthesis of polymethylene block copolymers and discovery of new polymerizable ylides. II. Synthesis and evaluation of molecularly imprinted polymer membranes.

摘要

This dissertation encompasses two main research areas. The first area in this dissertation focuses on the polyhomologation reaction for the synthesis of carbon backbone polymers one carbon at a time. Chapter 1 provides an outline of polyethylene's molecular structure, properties and morphology. Current catalysis and production process are surveyed to explain the formation of the molecular features that distinguish the different types of polyethylene. The last section of Chapter 1 explains the key features and applications of the polyhomologation reaction. In the polyhomologation reaction, organoboranes serve as the initiator and sulfur ylides function as the monomer. The carbon chain is built up one carbon at a time by repetitive homologation of alkyl substituents. The living nature of the polyhomologation reaction permits control of the molecular weight as well as functionality at either end of the polymer chain.; Chapter 2 discusses the reaction of tris(polymethylene)borane, the intermediate of the polyhomologation reaction, with oxygen. Routine processing of tris(polymethylene)borane involved concentration of toluene prior to addition of a THF solution of basic hydrogen peroxide. These operations can expose the organoborane intermediate to oxygen. The reaction of the organoborane with trace quantities of adventitious oxygen can result in a bimodal distribution consisting of a small peak comprising approximately 5% of the sample with an average molecular weight twice that of the principle polymer component. The mechanism is discussed and a mathematical simulation is carried out.; In Chapter 3, a procedure for the synthesis of poly(methylene- b-styrene) is described. The strategy unites two living polymerization reactions permitting control of the average DP of both blocks. The polystyrene block is installed first via a hydroxy functionalized TEMPO initiator. The polymethylene block was installed by the polyhomologation reaction. The thermal properties and the ability of the copolymer to compatibilzing PE and PS blends are examined.; Chapter 4 describes our efforts to discover new polymerizable ylides. A new family of ylides---(dimethylamino)aryloxosulfonium ylide has been successfully employed in the polyhomologation reaction. The ylides are available with extensive structural variation, which permits one to specify functionality on the main chain as well as at either end of the polymer.; The second area of the research focuses on the synthesis and evaluation of molecularly imprinted polymer membranes. The aim of Chapter 5 is to provide a comprehensive introduction to the field of molecularly imprinted polymer membranes in all its aspects including the synthesis, evaluation and applications. Molecular imprinting is a process for synthesizing materials that contain highly specific recognition sites for small molecules. Molecularly imprinted polymer membranes may provide a general approach for preparing membranes with high selectivities.; In Chapter 6 we report two different methods to synthesize molecularly imprinted polymer membranes. One method leads to establish a reproducible procedure for the preparation of thin film composite polymer membranes. These membranes can dramatically improved the flux rate without losing the selectivity compared to thick, free-standing membranes. Also described in Chapter 6 is preparation of molecularly imprinted polymer membranes for the peptide separation utilizing natural polymer cellulose triacetate as a membrane matrix.