Preparation And Characterizations Of Organic-inorganic Hybrid Zwitterionic Copolymers And Membranes

In this dissertation, a series of organic- inorganic hybrid zwitterionic copolymers and membranes containing sulfonic acidic groups or carboxyl acidic groups were synthesized by organic polymerization reaction and sol-gel reaction and characterized by both macroscopic and microscopic methods. Different preparation routes have great influences on the properties of the prepared organic-inorganic hybrid zwitterionic copolymers and membranes.1. Organic-inorganic hybrid zwitterionic copolymers containing sulfonic acidic groups was prepared and characterized; which was synthesized by grafted reaction of organic alkoxysilane onto the copolymer molecular chains, a subsequent sol-gel process and charged processes on functional group were carried out. Based on the addition reaction between isocyanic groups and alcohol groups, charged hybrid precursors PEG-[Si(OEt)₃]₂ were prepared by the reaction between 2,4-diisocyanate toluene and polyethylene glycol, and then reacted with Phenylaminomethyl triethoxysilane. A series of zwitterionic hybrid copolymers were prepared by the sulfonation of phenyl groups and the quaternary amination of tertiary amine groups alternately. The thermal stability of these zwitterionic hybrid copolymers is higher than 400℃.The characterization on ion exchange capacities shows the synthesis route has great influences on the charged content of ionic groups. The surface SEM images which demonstrate that the surface of zwitterionic hybrid copolymer (e) has some aggregated particles and form clusters regions in the hybrid matrix, shows the ionic interactions between those charged groups.2. Organic-inorganic hybrid zwitterionic copolymers containing carboxyl acidic groups was prepared and characterized. Free radical polymerization was employed to prepare hybrid precursors via acrylic acid (AA), 4-vinylbenzyl chloride (VBC) andγ-methacryloxypropyltrimethoxysilane (KH-570). Subsequently, sol-gel process and quaternary amination of benzyl groups were carried out to investigate the influence of silicone on the properties of hybrid zwitterionic copolymers and membranes. The prepared organic-inorganic hybrid zwitterionic copolymers and membranes revealed relatively high thermal stability after the introduction of siliceous monomer (KH-570). TGA and DrTGA analyses indicate that proper content of silicone monomer (KH-570) can improve the stability of these organic-inorganic hybrid zwitterionic copolymers and membranes; however, excessive silicone will reduce their thermal stability. It is indicated that the ion-exchange capacities, water content and the adsorptive capacity of copper ion of the prepared hybrid zwitterionic copolymers and membranes all decrease with the increasing content of silicone. Meanwhile, they decrease with the increasing coating times.