Solution-grown crystal of poly[bis(4-isopropylphenoxy)phosphazene]

The structural features of poly[bis(4-isopropylphenoxy)phosphazene] (PB(4-ip)PP) have been studied by electron microscopy, X-ray diffraction and differential scanning calorimetry techniques. Its orthorhombic lattice constants are determined as follows: a = 3,14 nm, b = 1,14 nm, c = 0,992 nm. The space group of this polymer is suggested to be P 2₁2₁2₁–D, and the molecular conformation of the chains possibly to be (trans₃cis)₂. This polymer exhibits a crystal/crystal transition at 86°C below its T(1) transition (120°C). The thermal behavior is similar to the characteristics of poly[bis(p-methoxyphenoxy)phosphazene].     

Separation of Cr ions from Co and mn ions by poly (bis(phenoxy) phosphazene) membranes

Poly(bis (phenoxy)phosphazene) was synthesized and cast by knife techniques into membranes supported on porous Inconel plates for separation testing. A solution of Cr³⁺, Co²⁺ and Mn^2/t+ nitrates was used as the feed solution in diffusion experiments conducted from 25 to 180°C. It was discovered that Co²⁺ and Mn²⁺ ions had much higher diffusion coefficients than Cr³⁺ ions through the membrane, with a maximum difference occurring near 100°C. The lower diffusion associated with Cr³⁺ ions is believed to be due to formation of polymerized hydrated Cr³⁺ ions that are too large to penetrate the membranes. Diffusion activation energies are reported.     

Environmentally responsive micelles from polystyrene–poly[bis(potassium carboxylatophenoxy)phosphazene] block copolymers

Amphiphilic diblock copolymers that contained hydrophilic poly[bis(potassium carboxylatophenoxy)phosphazene] segments and hydrophobic polystyrene sections were synthesized via the controlled cationic polymerization of Cl₃P?NSiMe₃ with a polystyrenyl–phosphoranimine as a macromolecular terminator. These block copolymers self‐associated in aqueous media to form micellar structures which were investigated by fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The size and shape of the micelles were not affected by the introduction of different monovalent cations (Li⁺, K⁺, Na⁺, and Cs⁺) into the stable micellar solutions. However, exposure to divalent cations induced intermicellar crosslinking through carboxylate groups, which caused precipitation of the ionically crosslinked aggregates from solution. This micelle‐coupling behavior was reversible: the subsequent addition of monovalent cations caused the redispersion of the polystyrene‐block‐poly[bis(potassium carboxylatophenoxy)phosphazene] (PS–KPCPP) block copolymers into a stable micellar solution. Aqueous micellar solutions of PS–KPCPP copolymers also showed pH‐dependent behavior. These attributes make PS–KPCPP block copolymers suitable for studies of guest retention and release in response to ion charge and pH. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2912–2920, 2005     

Poly[bis(2,2,2-trifluoroethoxy)phosphazene] superhydrophobic nanofibers

Nanofibers of poly[bis(2,2,2-trifluoroethoxy)phosphazene] were produced by electrospinning from solutions in tetrahydrofuran, methylethyl ketone, and acetone. The fiber diameter varied from 80 nm to 1.4 microm by changes in the concentration of the polymer solution. The electrospun nonwoven mats showed enhanced surface hydrophobicity compared to spun cast films with up to a 55 degrees increase in water contact angle. The hydrophobicity varied with fiber diameter and surface morphology, with contact angles to water being in the range of 135 degrees -159 degrees. A low value of hysteresis (<4 degrees) was recorded for the superhydrophobic surfaces. The extremely high hydrophobicity of these mats is a combined result of a fluorinated surface and the inherent surface roughness of an electrospun mat.     

Gas transport in poly [bis(trifluoroethoxy) phosphazene] above the T(1) transition

Gas permeation measurements were performed by the time-lag method for 13 gases in poly [bis(trifluoroethoxy) phosphazene] above the mesophase transition, T (1) transition, of the crystals. Hysteresis was found in the temperature dependence of the permeability coefficients for CO₂, O₂, and N₂ in the transition region as observed by dilatometry and differential scanning calorimetry. Independently the solubility of CO₂ was determined gravimetrically above and below T(1). Noticeable change and hysteresis were also observed in the temperature dependence of the solubility coefficients. Diffusion of CO₂ in the measophase is suggested from the permeation and sorption measurements. Gas transport parameters of CO₂ in the mesophase are estimated, and the contributions of the mesophase and the crystalline phase to gas transport are considered.     

Synthesis and self‐association behavior of poly[bis(2‐(2‐methoxyethoxy)ethoxy)phosphazene]‐b‐poly(propyleneglycol) triblock copolymers

Amphilic triblock copolymers with varying ratios of hydrophilic poly[bis (methoxyethoxyethoxy)phosphazene] (MEEP) and relatively hydrophobic poly(propylene glycol) (PPG) blocks were synthesized via the controlled cationic‐induced living polymerization of a phosphoranimine (Cl₃P?NSiMe₃) at ambient temperature. A PPG block can function as either a classical hydrophobic block or a less hydrophobic component by varying the nature of a phosphazene block. The aqueous phase behavior of MEEP‐PPG‐MEEP block copolymers was investigated using fluorescence techniques, TEM, and dynamic light scattering (DLS). The critical micelle concentrations (cmcs) of MEEP‐PPG‐MEEP block copolymers were determined to be in the range of 3.7–16.8 mg/L. The mean diameters of MEEP‐PPG‐MEEP polymeric micelles, measured by DLS, were between 31 and 44 nm. The equilibrium constants of pyrene in these micelles ranged from 4.7 × 10⁴ to 9.6 × 10⁴. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 692–699, 2009     

Plasma surface functionalization of poly[bis(2,2,2-trifluoroethoxy)phosphazene] films and nanofibers

Polyphosphazenes are a class of hybrid organic-inorganic macromolecules with high thermo-oxidative stability and good solubility in many solvents. Fluoroalkoxy phosphazene polymers also have high surface hydrophobicity. A method is described to tune this surface property while maintaining the advantageous bulk materials characteristics. The polyphosphazene single-substituent polymer, poly[bis(2,2,2-trifluoroethoxy)phosphazene], with flat film, fiber mat, or bead mat morphology was surface functionalized using an atmospheric plasma treatment with oxygen, nitrogen, methane, or tetrafluoromethane/hydrogen gases. Surface chemistry changes were detected by static water contact angle (WCA) measurements as well as X-ray photon spectroscopy (XPS). It was found that changes in the WCA of as much as 150 degrees occurred, accompanied by shifts in the ratio of elements on the polymer surface as detected by XPS. Overall this plasma technique provides a convenient method for the generation of specific surface characteristics while maintaining the hydrophobicity of the bulk material.     

聚双(6-咔唑基己氧基)磷腈的合成

以PCl5和NH4Cl为原料采用"一步法"合成了线型聚二氯磷腈(4);4与6-咔唑基己醇发生亲核取代反应合成了聚双(6-咔唑基己氧基)磷腈(5),其结构经1H NMR,31P NMR,IR和GPC表征。热分析结果表明,5具有良好的热稳定性和较高的玻璃化温度。     

Electrical properties of poly(bis(β-phenoxyethoxy)phosphazene) and its complexes

Electrical and dielectrical properties of poly(bis(-phenoxyethoxy)phosphazene) (I) and its complexes with various content ratios of AgSO₃CF₃ to monomeric unit (0.25/1 (II) and 0.5/1 (III) in molar ratio) were investigated.Dc conductivity of respective samples at 18 °C were 6.1×10^–12, 4.4×10^–9, and 7.1×10^–8 S/m.Dc conduction was considered to be due to ion hopping. Charge mobility ranged from 3×10^–12 to 6× 10^–11 m²/Vs depending on the applied field in sample II. In sample I, a tan peak was found which can be ascribed to molecular relaxation of main chains. The peak vanished upon introducing AgSO₃ CF₃. Temperature dependence of total conductivity ( _T ) measured byac method in the temperature range between –150 °C and 50 °C showed several peaks at the temperatures corresponding to the peak temperatures of tan. Total conductivities of respective samples at 100 kHz were 4.9×10^–7 (69 °C), 1.7×10^–4 (45 °C), and 1.5×10^–4(40°C)S/m.     

Effects of 60Co gamma rays on poly[bis(p-tolylamino)Phosphazene]

The behaviour of poly-[bis(p-tolylamino)phosphazene] under ⁶⁰Co gamma irradiation was investigated in chloroform, carbon tetrachloride, benzene, toluene and tetrahydrofuran. Viscosity, average molecular weights and spectral changes were used to follow the degradation. The degradation mechanism was interpreted in terms of a combined interaction of the polymer molecule with dissolved oxygen and radiolysis products of the solvent.     

聚双(对羟基苯甲酸甲酯)磷腈的合成及表征

通过一步法合成线性聚二氯磷腈(PDCP),并用对羟基苯甲酸甲酯与线性聚二氯磷腈(PDCP)反应合成聚双(对羟基苯甲酸甲酯)磷腈,运用~1HNMR、~(13)C NMR、~(31)P NMR及FT-IR对其结构进行了表征。DSC和TGA实验表明该聚合物的T_g有了明显的提高且具有较好的热稳定性。     

X-ray structure analysis of poly[di-(3,4-dimethylphenoxy)phosphazene]

The crystal structure of oriented poly[di-(3,4-dimethylphenoxy) phosphazene] (PDMP) was determined by x-ray diffraction. Unit-cell parameters were found to be a = 15.85, b = 19.43, and c = 9.85 Å. The unit cell is metrically orthorhombic with monoclinic space group P2₁. There were 48 refinable diffraction spots in the observed reciprocal lattice region, of which 28 were observed and 20 were unobserved. A refined model yielded the following residuals: R^(obs) = 0.162 and 0.138. It was shown that a two-chain unit cell with a [T₃C]₂ (trans, trans, trans, cis, trans, trans, trans, cis) backbone conformation was the correct structure. The dimethylphenoxy side groups were arranged in nearly parallel planes, slightly off-normal to the fiber c axis. The polymer chains are extremely tightly packed and contain close but reasonable steric contacts.     

Synthesis, characterization, and thermal stability of star-shaped poly(ε-caprolactone) with phosphazene core

Hexakis[p-(hydroxylmethyl)phenoxy]cyclotriphosphazene was synthesized by the reaction of hexachlorocyclotriphosphazene with the sodium salt of 4-hydroxybenzaldehyde and subsequent reduction of aldehyde groups to alcohol groups by using sodium borohydride. This compound was employed in initiating the ring-opening polymerization of ε-caprolactone. The resulting polymers were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The characterization data indicated the star-shaped PCL with phosphazene core were successfully synthesized with narrow molecular weight distribution and high yields. ¹H-NMR analysis was used to calculate the number-average molecular weight. The calculated result from NMR was closer to the theoretical data than that from GPC analysis. Polarizing optical microscopy (POM) combined with differential scanning calorimetry (DSC) was used to study the crystallization behavior of the star-shaped PCL. The result indicated that the highly branched architecture of star-shaped PCL resulted in interrupted crystallization form and subsequently lower melting temperature. Thermogravimetric analysis (TGA) carried out on the star-shaped PCL suggested that introduction of phosphazene rings strengthen the thermal stability of the resulting polymers.     

The atomistic simulation of the gas permeability of poly(organophosphazenes). Part 1. Poly(dibutoxyphosphazenes)

Self-diffusion and solubility coefficients of six gas molecules (He, Ne, O₂, N₂, CH₄, and CO₂) in two poly(dibutoxyphosphazenes)—poly[bis(n-butoxy)phosphazene] (PnBuP) and poly[bis(sec-butoxy)phosphazene] (PsBuP)—have been investigated by means of molecular simulation using the COMPASS molecular mechanics force field. Diffusion coefficients were obtained from molecular dynamics (NVT ensemble) using up to 3 ns simulation time. Solubility coefficients were obtained by means of a Grand Canonical Monte Carlo (GCMC) method. Results of both simulations were in generally good agreement with experimental data with the exception of the simulation results for gas solubility in PsBuP where differences from the data may be attributed to microcrystallinity of the experimental sample. In the case of diffusivity, diffusion coefficients correlated well with the square of the effective diameter of the diffusing gas. Similarly a good correlation was found between the solubility coefficients obtained by GCMC simulation of sorption isotherms and the Lennard-Jones potential well depth parameter, ϵ/k.The transition-state model of Gusev and Suter was used to determine free volume and free volume distribution for PnBuP, PsBuP, and poly[bis(iso-butoxy)phosphazene] (PiBuP). The diffusion coefficient for a given gas in each polyphosphazene was found to correlate exponentially with its accessible free volume fraction. A model for the distribution of accessible free volume, derived from the Cohen–Turnbull theory for the self diffusion of a liquid of hard spheres, was found to provide excellent fit with the simulation results.     

Radiation induced oxidative degradation of poly[bis(p-tolylamino)] phosphazene in chlorinated hydrocarbons

Degradation induced by ionizing radiations on polyphosphazenes, dissolved in chlorinated methanes, is the subject of this investigation. Both steady gamma and pulse radiolysis techniques have been employed.The labile sites for radical attack in poly[bis(p-tolylamino)] phosphazene were identified as the aniline N-H and benzyl C-H bonds of the pendant groups. All the primary radicals, by themselves or after peroxidation, can give rise to macroradicals by hydrogen abstraction from the polymer molecules. Appreciable crosslinking appeared only in the presence of quite a high concentration of oxygen, whereas, in its absence or after it had been consumed, practically no $\text{M}{}_{\mathrm{<mtext>w</mtext>}}$ changes were detected. Optical spectra of intermediates formed after pulse radiolysis are reported and attributed to radical-polymer charge transfer complexes, anilinium ions and toluidine radicals. p-Toluidine is formed as an end-product by hydrogen abstraction from polymer molecules. In solvents where hydrogen chloride can be formed, the amino functional group is affected.     

The thermal transition behavior of poly(bis(p-flourophenoxy)phosphazene)

The thermal transition behavior of poly(bis(p-fluorophenoxy)phosphazene) was studied as a representative aryloxy-substituted poly(organophosphazene) using X-ray diffraction, differential thermal analysis and density measurements. The crystal structure of-form contained in as-cast film had marked paracrystalline disorder. The crystal phase transformed into the mesophase atT(1) (110 140 °C). The structure of the-form observed in the mesophase was a representative hexagonal-packing of macromolecular chains which rotate around the chain axes. When the mesophase was cooled to room temperature, a more ordered crystal phase of the-form could appear. The most ordered crystal structure of the-form has a monoclinic unit cell with the following lattice parameters: a=18.9, b=13.2, c=4.90 Å, and=77°. The chain conformation is nearly planar cis-trans, which has been observed commonly in poly(organophosphazenes). The macroscopic deformation of the film sample was also examined, taking into account the microscopic deformation of the lamellar crystal due to the crystal-mesophase transition.     

Thermally stimulated currents in poly(bis(p-fluorophenoxy)phosphazene)

Thermally stimulated currents (TSC) were examined for poly(bis(p-fluorophenoxy)phosphazene) (PBFPP) film. TSC showed peaks at the glass transition temperature (Tg=–4 °C) and atT(1) (160 °C – 170 °C), where-form crystal phase transformed to mesophase of-form structure. Another peak was found atT _cc betweenTg andT(1). Linear relationship between polarization field and peak current ofT _cc -peak was found, which shows thatT _cc -peak was caused by motion of dipolar groups in crystalline phase. When heating (up to 200 °C) and cooling (down to 20 °C) thermal process was repeated,T _cc -peak shifted to higher temperature region approachingT(1) and simultaneously, the peak current ofT(1)-peak became smaller. Activation energy, time constant of dipolar relaxation and charge mobility were evaluated forT _cc -peak. From these results, it was concluded that-form and more ordered- form crystalline phases coexisted in PBFPP once heated aboveT(1) and the content of- form phase increased by repeated thermal hysteresis.     

The x-ray structure determination and semiempirical PM3 calculations of 2,4,4,6,6-pentachloro-2-(piperidyl)cyclotri(phosphazene)

The structure of 2,4,4,6,6-pentachloro-2-(piperidyl)-cyclotri(phosphazene) ( 1 ) was determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the orthorhombic space group P_bea with Z = 8 and unit cell dimensions a = 8.316(2), b = 17.261(3), and c = 22.007(4) Å. The experimentally obtained structural parameters for compound 1 compare well with those calculated at the semiempirical PM3 level of theory. These results give credence to the PM3-calculated structure of 2,4,4,6,6-pentaazido-2-(piperidyl)cyclotri(phosphazene) ( 2 ) for which presently there are no experimental data available.

1 Non-SI units employed: 1 kcal≈︁4.184 kJ, 1 Å = 10⁻¹⁰ m since these units are still used in computational chemistry, we employed them throughout this article.

© 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 283–286, 1997.     

New Acid-Polyfunctional Water-Soluble Phosphazenes: Synthesis and Spectroscopic Characterization

Poly [bis(phenoxy)] phosphazene sulfonic acid and its mixed substitution derivatives containing N-methylsulfonamide, sulfonylaminoacetic, and free sulfonic acid functions have been obtained and characterized by IR and ¹H-, ³¹P-, ¹³C-NMR spectroscopy. The polymers are all water soluble. Poly [bis(4-benzoylphenoxy)] phosphazene sulfonic acid could not be obtained due to chain degradation during the synthesis.     

Synthesis, characterization and hydrolytic degradation of linear and crosslinked poly[(glycino ethyl ester)(allyl amino)phosphazene]

Polyorganophosphazenes substituted by glycino ethyl ester and allylamine with different ratios were synthesized and their structures were characterized by ¹H NMR, ³¹P NMR and FTIR. Via the crosslink reaction, a novel biodegradable crosslinked polyorganophosphazene material was obtained. DSC and FTIR spectra indicated the occurrence of crosslink. Hydrolysis studies were also performed to compare the crosslinked polymers with linear ones. The co-substituted polyorganophosphazenes with more allylamine at pendant groups exhibited a lower degradation rate than poly[bis(glycino ethyl ester)phosphazene] and crosslinked polyphosphazenes had an even lower degradation rate. SEM photographs characterized the surface of polyphosphazenes films after hydrolytic degradation, confirming that uncrosslinked ones had outstanding hydrolytic evidences at the surface while the crosslinked ones only had sporadic small erosion holes, remaining much smoother.