Synthesis Of Side Chain Fluoroalkyl Polysiloxane Via Single Electron Trasfer Reaction And Its Property

In this dissertation, a series of side chain fluoroalkyl polysiloxanes containing different bridged groups were synthesized via fluoroalkylation of the C=C side chain of the polysiloxanes by the single electron transfer followed by reduction and elimination reactions. The thin films of fluorine-containg polysiloxane products were prepared by spin coating tech. The surface energy and chemical composition of the films were tested by X-ray photorlectron spectroscopy(XPS) and the surface contact angle, and the surface morphology was observed by atomic force microscopy(AFM). The relation between structures and properties of fluoropolysiloxanes with different bridged groups were studied systematically.Firstly, vinylpolysiloxane was prepared by hydrolytic-condensation using trimethylchlorosilane and methyl vinyldichloridesilane as raw materials. After iodine-containing fluoroalkyl polysiloxanes were obtained via single electron transfer reaction initiating by sodium dithionite under mild conditions, fluoropolysiloxanes containing carbon-carbon bridged group were prepared by reduction and elimination reactions of side-chain perfluoroalkyl iodides. The surface energy and chemical composition of the fluoropolysiloxanes were studied and the surface morphology was observed. The result showed that the-CH2CH2- bridging group can help to increase the surface fluorine content of the resulted fluoropolysiloxane films and more likely to induce the orientation of side chain fluoroalkyl at high temperature. As a result, the fluoropolysiloxane has been obtained with lower surface energy and better water repellent property.Secondly, poly(cyclopentadienyl)siloxane was prepared as intermediate product by substitution and hydrolysis reactions using methyltrichlorosilane and sodium cyclopentadienylide as raw materials. After epoxidation of the side-chain cyclopentadienyl groups, the epoxy modified silicone oil was obtained and applied on cotton fabric finishing. The result showed that the epoxy modified silicone oil could provide flexibility and elasticity, and restrain the yellow degeneration of the amino silicone oil effectively. Moreover, the fabric possesses the better wash-ability after finishing. In addition, fluoroalkylation of cyclopentenyl side-chain was achieved via the single electron transfer addition reaction followed by reduction reaction. The change of the surface energy of poly(cyclopentadienyl)siloxane before and after fluoroalkylation were studied with the measured surface energy to be 2.57×10-2N/m and 2.14×10-2N/m respectively. Compared with the roughness of the polysiloxane film before fluoroalkylation, the roughness of the fluoropoly(cyclopentenyl)siloxane film increased up to 34%.Lastly, poly(silsesquioxane)methylsiloxane was prepared by bonding the vinylsilsesquioxanes onto the side chain of the polysiloxane. This polyvinylsilicone was suffered from single electron transfer addition and reduction reaction of the side chain to get the polyfluoroalkyl silicone. The thin film of polyfluoroalkyl silicone was prepared with excellent water repellent property due to the rough fluorine containing morphology with numerous pinnacles. The silsesquioxane modified fluorosilicone has been identified to posess good thermal stability.