Papers by Keyword: Polyphosphazene

Abstract: Poly[bis(trifluoroethoxy)phosphazene] (PBFP) can be prepared via thermal ring-opening polymerization (ROP) of hexachlorotriphosphazene ((PNCl2)3) or ambient temperature cationic living polymerization (ALP) of monomeric Cl3P=NSiMe3, followed by introduction of OCH2CF3 groups via standard salt metathesis protocols. The resultant polymer morphology is dependent upon synthetic methodology, processing method (e.g. solvent casting, heat cycling, etc.) and the presence of inorganic nanoparticles, which were found to inhibit crystallization. 1H, 19F and 31P solid-state NMR spectroscopy was employed to investigate crystallization in solvent cast and heat-treated samples of pure PBFP and composites of nano-crystalline TiO2 doped PBFP.

Abstract: Uniform cyclomatrix polyphosphazene spheres with diameter of about 410 nm were firstly synthesized rapidly at room temperature by precipitation polymerization of hexachlorocyclotriphosphazene with 4,4′-sulfonyldiphenol, using triethylamine as acid-acceptor and acetonitrile as solvent. Then, monodisperse carbon spheres with abundant micropores were produced by carbonization of the polyphosphazene spheres at a high temperature under a nitrogen atmosphere. As-produced carbon spheres were well characterized by SEM, TEM, EDX, and N2 adsorption technique. Results show that the carbon spheres possess an average diameter of 320 nm, a BET surface area of about 752 m2·g-1, a total pore volume of 0.55 m3·g-1, and a micropore size distribution.

Abstract: Phosphorus containing biopolymers have been synthesized and studied as polymeric candidates for potential tissue engineering applications. The presence of phosphorus in the polymeric structure may improve the biocompatibility of polymers by enhancing their tissue contact. One aim of this study was to examine the chain extending reaction of poly(ε-caprolactone), PCL, using ethyldichlorophosphate as a coupling agent. A preliminary survey was done to find out whether the presence of phosphoester units in a rapidly degradable polymeric structure improves the Ca phosphate formation on PCL. Another aim of this study was to synthesize one kind of polyphosphazene, i.e. poly[bis(methacrylate)]phosphazene, PMAP. In addition, a preliminary biomineralization study for PMAP polymer was carried out. The results of the biomineralization studies indicated some bioactivity of both biopolymers.

Abstract: A novel phosphazene cyclomatrix network polymer was synthesized via nucleophilic displacement of activated nitro groups of tri(4-nitrophenoxy)tri(phenoxy) cyclotriphosphazene with the hydroxyls of bisphenol A. Then, thermal properties of the polymer was investigated using dynamic thermogravimetric analysis (TGA) in air, pyrolysis and combustion experiments. According to the relation among the pyrolysis residue (CR) at 850°C, the char-forming tendency (CFT) of every structural unit in polymer and the limiting oxygen index (LOI), CFT of the structural unit (-P=N-)3 and the LOI of the polymer were calculated as 35.04 and 34.3 respectively, which provided theoretical parameter for designing the cyclomatrix- or cyclo- phosphazene polymers with highly thermal and flame-retardant properties.