Studies On Organic-Inorganic Hybrid Film Materials

A novel crosslinking agent containing silicon-hydrogen atom and trimethoxylsilicon group was synthesized by controlling 1 to 2 molar ratio of 2,4,6,8-tetramethylcyclotetrasiloxane and vinyltrimethoxyl-siloxane. A PMDS hybrid membrane was also prepared by using the crosslinking agent, a silicone rubber containing vinyl groups of 10 mol% and tetraethoxysilicone (TEOS) as the matrix material. There are three types of the crosslinking reactions in membrane-forming process. They include an addition reacting between the silicon-hydrogen atom and the vinyl group, hydrolyzation and condensation themselves and between trimethoxylsiloxane and TEOS, respectively. The chemical and morphology structure of the hybrid membranes were characterized by using FT-IR and SEM and their mechanical properties were also measured. The hybrid membrane containing mass fraction of 25.0 % of TEOS showed a good membrane-forming property and the best mechanical performance as well as the best oxygen-enriching property. For example, at 30℃ and 0.05 MPa Po2 and ao2/N2 were 370 Barrer and 3.45, respectively. As the TEOS content in the membranes increased, .Po2 and Pn2 decreased gradually, but ao2/N2 firstly increased and then decreased obviously.To advance further permeability coefficients and separation factor, we added Co(II) salt complex into the membrane as O2 carrier. Oxygen permeability coefficient of 690 Barrer and oxygen/nitrogen separation coefficient of 3.42 were obtained at 20℃ and pressure difference of 0.05 MPa for the membrane containing vinylacetic acid cobalt of 10% (mass fraction).Furthermore, a novel sol-gel procursor was synthesized by the hydrosilylation of 2,4,6,8-tetramethylcyclotetrasiloxane with vinyltrimethoxysilane. Transparent hybrid coatings were obtained via sol-gel process of the synthetical procursor and tetraethoxysilane (TEOS). The procursor and the hybrid coatings were characterized by FT-IR analysis. The thermogravity analysis(TG) showed that the heat stabilities of the hybrid coatings increased with the increasing of SiO2 content. The properties of the hybrid coatings such as adhesion, lightness, pencil hardness, impact resistance and abrasion resistance were tested.