The Study And Synthesis Of Polyphosphazenes And Their Derivatives

Inorganic polymers and their substitutes with a backbone of alternating phosphorus and nitrogen atoms, known as polyphosphazenes, have attracted growing attention in recent years. Due to the special structure of polyphosphazenes, the chlorine atoms can be replaced by the organic groups to provide useful polymers. The properties of the resulting poly(organophosphazene) are determined by the type of alkoxy or aryloxy substituents coupled to the P-N backbone of the polymer. Polyphosphazenesthave the characters with both activity and stability, which is reflected from that they have a variety of functions under nucleophilic reaction and the resistance of acid, alkali and heat.Polyphosphazenes comprise a relatively new class of polymers that show promise for further development, which are used for aviation and spaceflight, shipping plant, petroleum and chemical engineering. Many such polymers with a variety of substitutions at the phosphorus have been prepared, and they often exhibit useful properties including fire retardancy, low-temperature flexibility, resistance to chemical attack, and biocompatibility among others. Polyphosphazenes were in research just in recent years in China although some oversea scholars have been studyingthem since nineteenth century, which weren't produced in factory. In order to accelerate the development and progress of polyphosphazenes, it is necessary to study the synthesis of hexachlorocyclotriphosphazene, poly(dichlorophosphazene) and their additions.This study began with the fundamental material of polyphosphazenes -hexachlorocyclotriphosphazene, using the traditional synthesis method. By analyzing the influential factors - temperature, time, the ratio of ammonium chloride and phosphorus pentachloride, catalyst, nitrogen and controlling the speed of dropping phosphorus pentachloride ect, the reaction conditions were optimized (temperature: 128Cor so; time: 5h; the optimized ratio ofphosphorus pentachloride and ammonium chloride: 1 : 1.4; catalyst: MgCl2 6H2O with pyridine) and hexachloro- cyclotriphosphazene was successfully synthesized, The structure and composition of the product was confirmed by FT-IR, 31P-NMR and monitoring the melt point.With the improvement of the style of heating (wax bath) and reaction container (three necks vacuum piston), using the method of direct heating, the paper produced the poly(dichlorophosphazene) from self-made material - hexachlorocyclotriphosphazene and then used FT-IR, 31P-NMR to confirm it.By nucleophilic reaction, the paper produced the corresponding substitutes respectively using the hexachlorocyclotriphosphazene andpoly(dichlorophosphazene).