Hexachlorocyclotriphosphazene Research Articles

Synthesis of cyclophosphazene bridged mesoporous organosilicas for CO2 capture and Cr (VI) removal

Cyclophosphazene bridged mesoporous organosilicas (CPMOs) were synthesized by condensation of (3-aminopropyl)triethoxysilane (APTES) and phosphonitrilic chloride trimer (PNC) using cetyltrimethylammonium bromide (CTABr) as structure directing and tetraethyl orthosilicate (TEOS) as co-condensing agents under basic condition. Five samples were prepared by varying the molar ratios of APTES:TEOS (1:0, 1:2, 1:3, 1:4 and 1:8). The specific surface area of the CPMOs varies from 34 to 1034 m2 g−1 and pore volume between 0.05 and 0.99 cm3 g−1, depending upon the APTES:TEOS ratios. The CPMO-8 show maximum CO2 uptake of 2.19 mmol g−1 at 273 K. Adsorption potential of the CPMOs for Cr (VI) removal in the aqueous solution was investigated by varying contact time, pH, initial metal ion concentration and temperature. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm by linear regression analysis. In addition, the kinetic analysis revealed that the overall adsorption process was successfully fitted with the pseudo-second-order kinetic model. The maximum Cr (VI) adsorption capacity of 99.24 mg g−1 was observed for the CPMO-4. The thermodynamics studies indicate a spontaneous exothermic process with negative ΔG, and ΔH of −1.808 kJ mol−1. The ΔS was calculated to be 10.718 J mol−1 K−1.

A high temperature polymer of phthalonitrile‐substituted phosphazene with low melting point and good thermal stability

ABSTRACTA phthalonitrile‐substituted phosphonitrilic monomer has been synthesized from phosphonitrilic chloride trimer and then polymerized with addition of 4‐(hydroxylphenoxy)phthalonitrile (HPPN). The chemical structures of the phosphonitrilic monomer and polymer were characterized by Fourier Transform Infrared spectroscopy (FT‐IR) and proton Nuclear Magnetic Resonance spectroscopy (1H NMR). Curing behaviors and thermal stabilities of the polymer were investigated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Analysis showed that the monomer has large processing temperature window and good thermal stability. Apparent activation energy, initial curing temperature (Ti), curing temperature (Tp), and termination curing temperature (Tf) of the phosphonitrilic polymer were explored. Dynamic mechanical analysis (DMA), glass transition temperature (Tg) were studied, and limiting oxygen index (LOI) were estimated from the van Krevelen equation, which indicates the polymer process high modulus and good flame retardance. Micro‐scale combustion calorimetry (MCC) was also used for evaluating the flammability of the polymers. Postcuring effects were explored, showing excellent thermal and mechanical properties with postcuring. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42606.

Study on the Synthesis and Application in the Polycarbonat of Silicone- Cyclophosphazene Flame Retardant

Silicone-cyclophosphazene (SCP) as a flame retardant was synthesized using hydroxyl terminated polydime thylsiloxane(PDMS-OH) and hexa cyclophosphazene silicone oil and phosphonitrilic chloride trimer(HCCTP) as the precursors, The properties of SCP-modified polycarbonat(PC) such as thermal stability, flame retardant properties and carbon layer after combustion were analyzed. It was found that the target product was SCP, as evidenced by infra-red spectrum (IR)and nuclear magnetic resonance(31P-NMR) spectra results. The PC/SCP composite had higher thermal stability, with higher amount of carbon residue at both initial degradation temperature and 800 oC. When the addition of SCP was 10 wt.% in the PC/SCP composite, the oxygen index increased from 28 to 34%, and a V-0 level was achieved on UL – 94 test. Also, a compact structure of the residue carbon layer after combustion was observed.

Preparation and characterization of cyclotriphosphazenekeratin/viscose fibers

The aim of this study is to develop a flame-retardant viscose fiber using the phosphazene derivative of a natural polymer. Hexachlorocyclotriphosphazene (HCCTP) and keratin were used as the raw materials to synthesize cyclotriphosphazenekeratin (CCTPK). The Fourier transform infrared spectroscopic results indicate that CCTPK was successfully synthesized. The thermal analysis shows that the introduction of phosphazene into keratin lowered the primary decomposition temperature, increased the decomposition rate, and caused less weight loss. CCTPK blended viscose fibers were prepared by the wet spinning method, and the properties of the fiber were investigated. Limiting oxygen index of the flame-retardant fiber containing 10 % flame retardant was 28.6 %, which decreased to 27.5 % after 30 washing cycles. After burning, the scanning electron microscopy image showed an inflated carbonized coat on the fiber surface. The effect of CCTPK on the mechanical properties of the fibers was insignificant. CCTPK was compatible with keratin, and the flame retardancy of the viscose fiber was significantly improved.

Fluorescent and Cross-linked Organic–Inorganic Hybrid Nanoshells for Monitoring Drug Delivery

Functionalized and monodisperse nanoshells have attracted significant attention owing to their well-defined structure, unique properties, and wide range of potential applications. Here, the synthesis of cross-linked organic-inorganic hybrid nanoshells with strong fluorescence properties was reported via a facile precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) and fluorescein on silica particles used as templates. The resulting poly(cyclotriphosphazene-co-fluorescein) (PCTPF) nanoshells were firm cross-linked shells with ∼2.2 nm mesopores that facilitated the transport of drug molecules. The fluorescent nanoshells also exhibited excellent water dispersibility and biocompatibility; thus, they can be considered as ideal drug vehicles with high doxorubicin storage capacity (26.2 wt %) and excellent sustained release (up to 14 days). Compared to doxorubicin (DOX) alone, the PCTPF nanoshells more efficiently delivered DOX into and killed cancer cells. Moreover, the PCTPF nanoshells also exhibited remarkable fluorescent emission properties and improved photobleaching stability in both suspension and solid state owing to the covalent immobilization of fluorescein in the highly cross-linked organic-inorganic hybrids. The exceptional fluorescent properties enabled the release of DOX as well as the distribution of nanoshells and DOX to be monitored.

Synthesis, structural characterization and anti-carcinogenic activity of new cyclotriphosphazenes containing dioxybiphenyl and chalcone groups

2,2-Dichloro-4,4,6,6-bis[spiro(2′,2″-dioxy-1′,1″-biphenylyl]cyclotriphosphazene (2) was synthesized from hexachlorocyclotriphosphazene (HCCP) and 2,2′-dihydroxybiphenyl. The mixed substituent chalcone/dioxybiphenyl cyclophosphazenes (2a–h) were obtained from the reactions of (2) with hydroxy chalcone compounds in K2CO3/acetone system. The chalcone-cyclophosphazene compounds were characterized by elemental analysis, FT-IR, 1H, 13C, 31P NMR techniques. In vitro anti-carcinogenic activities of all compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Anti-carcinogenic activity of the compounds (2a–h) against androgen-dependent (LNCaP) and independent (PC-3) human prostate cancer cell lines were investigated. Our results indicate that the chalcone-phosphazene compounds (2a–h) have anti-carcinogenic activity on PC-3 and LNCaP cell lines (p<0.05). The effective dose of the compounds was determined as 100μM.

Improving the flame retardancy of polyamide 6 by incorporating hexachlorocyclotriphosphazene modified MWNT

A nitrogen-, phosphorus- and chlorine-containing flame retardant, hexachlorocyclotriphosphazene (HCTP), has been covalently grafted onto the surface of multi-wall carbon nanotubes (MWNT) to obtain MWNT-HCTP. Polyamide 6 (PA6)/MWNT composites were then prepared via melt compounding. The flammability of PA6/MWNT composite was characterized by cone calorimetry, limiting oxygen index (LOI) and UL-94 tests. The results showed that peak heat release rate of samples containing 3 wt% MWNT-HCTP was only 460 kW/m2, which decreased by 35.2% compared with that of a neat PA6 sample. The LOI value was increased from 22.7% to 26.5%, and UL-94 test performance was also significantly improved by the presence of MWNT-HCTP. Scanning electron microscope (SEM) and optical microscope analysis showed that modified MWNT had a better dispersion and compatibility in PA6 than unmodified MWNT. The composition of residue chars and volatile products was investigated by SEM/energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric-FTIR, respectively. It was proposed that grafted HCTP was mainly functioned in the condensed phase, where P, N can synergistically promote char formation and Cl element can catch free radicals to terminate the chain reaction during combustion of the PA6 composite. Copyright © 2014 John Wiley & Sons, Ltd.

Synthesis of New Hexakis-Heterocyclic Compounds and their Use in the Formation and Stabilization of Au and Ag Nanoparticles

The stabilization of nanoparticles in solution is a challenge of major proportions, and avoiding the formation of aggregates and eventual coalescence of particles is directly linked to the conservation of its unique properties. In this work, we reported the synthesis of two hexakis-heterocyclic compounds, containing the tetrazole or 2-amino-1,3,4-thiadiazole group, respectively. The hexa-heterocyclic compounds were used in the synthesis and stabilization of Au and Ag nanoparticles. To obtain these molecules was used phosphonitrilic chloride trimer compound as core, which reacted with phenols properly substituted in theparaposition with either cyano or aldehyde group. The cyano group was successfully converted to the corresponding tetrazole using a 1,3-dipolar cycloaddition reaction with ammonium azide generatedin situ. In the case of aldehyde derivative, it was converted to the corresponding thiosemicarbazone, which was further cyclized using FeCl3. Compounds were characterized by RMN and IR spectroscopy. The UV-Vis spectroscopy was used for nanoparticles analysis.

“Fastening” Porphyrin in Highly Cross-Linked Polyphosphazene Hybrid Nanoparticles: Powerful Red Fluorescent Probe for Detecting Mercury Ion

It is a significant issue to overcome the concentration-quenching effect of the small fluorescent probes and maintain the high fluorescent efficiency at high concentration for sensitive and selective fluorescent mark or detection. We developed a new strategy to "isolate" and "fasten" porphyrin moieties in a highly cross-linked poly(tetraphenylporphyrin-co-cyclotriphosphazene) (TPP-PZS) by the polycondensation of hexachlorocyclotriphosphazene (HCCP) and 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (TPP-(OH)4) in a suitable solvent. The resulting TPP-PZS particles were characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), (31)P nuclear magnetic resonance (NMR), and ultraviolet and visible (UV-vis) absorption spectra. Remarkably, TPP-PZS particles obtained in acetone emitted a bright red fluorescence both in powder state and in solution because the aggregation of porphyrin moieties in "H-type" (face-to-face) and "J-type" (edge-to-edge) was effectively blocked. The fluorescent TPP-PZS particles also showed superior resistance to photobleaching, and had a high sensitivity and selectivity for the detection of Hg(2+) ions. The TPP-PZS particles were therefore used as an ideal material for preparing test strips to quickly detect/monitor the Hg(2+) ions in a facile way.

Preparation and Characterization of Flame-Retardant Viscose Fiber Treated with TAECTP

In this paper, hexachlorocyclotriphosphazene (HCCTP) was used as a raw material to synthesize triaminoethyloxy cyclotriphosphazene (TAECTP). After-finishing method was applied to the preparation of flame-retardant viscose fibers. LOI results showed that TAECTP was intrinsically flame retardant. After burning, inflated carbonized coat was found on the fiber surface. Thermogravimetric analysis (TG) indicated that primary decomposition temperature of the fiber moved up about 30°C, as compared with untreated viscose fiber. Loss on mechanical properties of fibers was insignificant. The introduction of TAECTP was compatible and the flame retardancy of viscose fiber was greatly improved with limited negative impact.

Grafting of amine-capped cross-linked polyphosphazenes onto carbon fiber surfaces: a novel coupling agent for fiber reinforced composites

The performance of carbon fiber reinforced composites is to a great extent dictated by the interfacial adhesion strength between the fibers and matrix. In order to improve the interfacial properties of carbon fiber/polypropylene (PP) composites, a new surface treatment has been developed to graft the amine-capped cross-linked polyphosphazenes (ACP) onto carbon fibers as a novel coupling agent through in situ polycondensation between hexachlorocyclotriphosphazene (HCCP) and 4,4′-diaminodiphenyl ether (DDE) under mild reaction conditions, and maleic anhydride grafted PP (M-PP) was used as the matrix. The chemical composition of the modified carbon fibers was verified by Fourier-transform infrared (FTIR) spectra and X-ray photoelectron spectra (XPS). The surface morphologies of the modified carbon fibers were detected by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The interfacial shear strength (IFSS) between carbon fibers and the matrix was investigated by a microbond test. The grafted ACP with a quantity of amine groups uniformly covered the carbon fiber surfaces, which results in strong interfacial adhesion between the modified carbon fibers and M-PP. The results of the test reveal a significant improvement of IFSS in the ACP grafted carbon fiber composites with an increase of 223.0% compared to the unmodified carbon fiber composites. In this work, we propose a facile and effective method for improving the interfacial properties of carbon fiber composites by grafting a novel coupling agent.

Direct synthesis of phosphorus and nitrogen co-doped monolayer graphene with air-stable n-type characteristics.

Large-area substitutional phosphorus-nitrogen co-doped monolayer graphene is directly synthesized on a Cu surface by chemical vapor deposition using molecules of phosphonitrilic chloride trimer as the phosphorus and nitrogen sources. The doping levels of both phosphorus and nitrogen atoms decrease as a function of the growth temperature. In contrast, the doping effect is enhanced with temperature because of the formation of more stable bond configurations for dopants at higher temperatures. Moreover, the doping amount of nitrogen atoms is always higher than that of phosphorus atoms at all used temperatures. The phosphorus and nitrogen co-doped graphene exhibits remarkable air-stable n-type characteristics. This work demonstrates the critical role of phosphorus atoms in achieving enhanced electron donation compared to nitrogen atom doping of graphene, and is important for various applications associated with the need for air-stable n-type graphene materials.

ChemInform Abstract: A Facile and Effective Synthesis of 2‐Azetidinones via Phosphonitrilic Chloride.

AbstractThe cycloaddition reaction between imines and carboxylic acids is developed using phosphonitrilic chloride as condensating agent.

A comparative structure–property study of polyphosphazene micro-nano spheres

Novel fluorinated cross-linked polyphosphazene micro-nano spheres have been prepared by precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) monomer. The influence of molecular structure on the morphology of polyphosphazene micro-nano spheres was investigated by SEM and TEM. The micro-nano spheres were also characterized by Fourier transforms infrared, X-ray photoelectron spectroscopy and thermo gravimetric analysis. The results indicate that the 5 % thermal degradation temperature is 366 °C. It was found that a silicon wafer dip-coated with thus prepared micro-nano spheres has a water contact angle as high as 137° ± 1.5°. Furthermore, the effects of the concentration of HCCP and ultrasonic power on the morphology were also discussed.

Modified montmorillonite and its application as a flame retardant for polyester

ABSTRACTA novel flame retardant composed of montmorillonite (MMT) and hexachlorocyclotriphosphazene (HCCP) was prepared in this study. MMT was chemically bonded with HCCP via a 3‐aminopropyltriethoxysilane (KH‐550) coupling agent. The structure was characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and NMR. The preliminary application for improving the flame retardancy of poly(ethylene terephthalate) (PET) was investigated by means of the limited oxygen index, the vertical burning test, and thermogravimetric analysis. Scanning electron microscopy was used to investigate the morphology of the char residue. The results show that the novel flame retardant had excellent fire retardancy; that is, the sample achieved an increased UL‐94 V‐0 rating and limited oxygen index value of 31.5. The residue of the flame‐retarded PET increased to 14.7% compared to the 6.2% value of pristine PET. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39625.

A facile and effective synthesis of 2-azetidinones via phosphonitrilic chloride

The Staudinger reaction of imines to β-lactams was successfully achieved with substituted acetic acid and phosphonitrilic chloride in one-pot under mild conditions. Several types of β-lactams, especially 3-electron-withdrawing group β-lactams, can be synthesized by this versatile and efficient method in good to excellent yields. This method is simple, clean, and the by-products were removed by simple aqueous work-up. The effects of solvents, molar ratio of reagent, and the temperature were considered.

ChemInform Abstract: Phosphonitrilic Chloride as an Efficient Reagent for the Synthesis of β‐Sultams.

AbstractOptimized conditions for the synthesis of β‐sultams, which are of interest in antibiotic research, from imines and sulfonic acid allow simple aqueous work‐up to remove water‐soluble by‐products.

Hexachlorocyclotriphosphazene (HCCP)-Mediated Direct Formation of Thioethers and Ethers from Quinazolin-4(3H)-ones

A hexachlorocyclotriphosphazene (HCCP)-mediated direct formation of quinazoline (thio)ethers from quinazolin-4(3H)-ones has been developed. Treatment of quinazolin-4(3H)-ones with HCCP, diisopropylethylamine (DIPEA), and thiophenols resulted in formation of the corresponding 4-arylthioquinazoline derivatives in moderate to excellent yields. This method has also been utilized to prepare 4-aryloxyquinazoline and 4-alkoxyquinazoline derivatives using phenols and sodium alkoxides as the nucleophiles.

Study on Synthesis of Cyclotriphosphazene Containing Aminopropylsilicone Functional Group as Flame Retardant

A novel non-halogen flame retardant APESP, cyclotriphosphazene containing six aminopropyltriethoxysilicone functional groups N3P3[NH(CH2)3Si(OCH2CH3)3]6, was synthesized by menas of SN2 nucleophilic substitution reaction, using hexachlorocyclotriphosphazene(HCCP) and 3-aminopropyltriethoxy-silane (KH550) as material. Firstly the industrial grade HCCP was purified through recrystallization and sublimation. Then the reaction process was investigated to prompt the yield, and the optimum reaction conditions were as follows: triethylamine as acid-binding agent, tetrahydrofuran as solvent, HCCP/KH550/triethylamine molar ratio 1:7.2:7.2, dripping time: 1 hour, temperature: 67°C and reaction time: 20h. Maximum APESP yield reached 94.3%. The chemical structure and purity was characterized by element analysis, Fourier-transformed infrared spectroscopy (FTIR), mass spectrum, gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) analysis. The results showed that the structure of synthesized product is consistent with the theoretical structure, in which the chlorine atoms were completely substituted. The charge distribution calculation of HCCP and KH550 confirmed the reaction mechanism.

Fabrication of core/shell structured NaYF4:Yb3+, Er3+/polyphosphazene upconversion nanophosphors functionalized with abundant active amino groups

Here we report the synthesis of highly cross-linked organic–inorganic hybrid polymer protected NaYF4:Yb3+, Er3+ upconversion nanocrystals (UCNCs) with efficient NIR-to-visible upconversion luminescence. Hexagonal UCNCs with uniform size and efficient upconversion performance were synthesized via a solvothermal approach. In-situ polycondensation between hexachlorocyclotriphosphazene (HCCP) and p-phenylenediamine (p-PDA) was conducted on the surface of UCNCs to form highly cross-linked organic–inorganic hybrid polymer shell. The results from this study revealed that the novel core/shell structured nanophosphors not only maintained efficient upconversion fluorescence, but also gained good water dispersability, chemical modification ability of the surface because of the abundant amino groups tagged on the surfaces of the polyphosphazene shell. The content of amino groups on the surface can reached as high as 69μmol/g.