Preparation and Properties of Three Novel Poly(phosphazene-aryl amide)s Containing Cyclotriphosphazene Structures

摘要

1,1,3,5-tetraphenoxy-3,5-bis(4-aminoanilino)cyclotriphosphazene, 1,1,3,5-tetraphenoxy-3,5-bis[4-(4-aminophenysulfone) anilino)]cyclotriphosphazene, and 1,1,3,5-tetraphenoxy-3,5-bis(N,N0-ethanediamine)cyclotriphosphazene were synthesized in two steps from the p-Phenylenediamine, 4,40-diaminodiphenylsulfone, and ethylenediamine via nucleophilic substitution and catalytic reduction with hexachlorocyclotriphosphazene. Three novel aromatic polyamides such as poly(cyclotriphosphazene-p-phenylene amide), poly (cyclotriphosphazene-p-sulfuryl amide), and poly(cyclotriphosphazene-ethyl amide) were synthesized from these diamines by direct polycondensation reaction with terephthaloyl chloride and pyridine in N-methyl pyrrolidone, respectively. The chemical structures of the diamine monomers and three novel poly(cyclotriphosphazene-aryl amide)s were characterized by Fourier Transform Infrared, (~1H and ~(31)P) Nuclear Magnetic Resonance, and Elemental Analysis. The thermal properties of the polyamides were determined by Differential Scanning Calorimetry and Thermogravimetric Analysis (TGA). The crystallization behaviors of the polyamides were studied by Wide-ray X-ray diffraction, and the morphology of the pyrolysis residues were observed by Scanning Electron Microscope. The three poly(cyclotriphosphazene-aryl amide)s with amorphous structure would exhibit an enhanced solubility in polar aprotic solvents and a superior thermal stability with initial decomposition temperature being at about 198-259℃. TGA curves of the poly(cyclotriphosphazene- aryl amide)s exhibit mainly three thermal decomposition steps, and the poly(cyclotriphosphazene-p-phenylene amide) presents the highest solid residue rate 62.6% heated to 600℃. In the morphology analysis of the poly(cyclotriphosphazene-aryl amide) solid residues, organophosphorus gelatum forms in the surface layer were observed.