一锅煮法合成聚二(p-乙氧羰苯氧基)磷腈

在无水K2CO3催化作用下,用一锅煮法合成了聚二(p-乙氧羰苯氧基)磷腈,产率70%,用IR3、1PNMR、1HNMR、13CNMR对其结构进行了确证,蒸汽压分子量测定法测定了数均分子量。     

Photochemical behavior of poly(organophosphazenes). I. Poly[bis(p-tolylamino)]phosphazene

The photolysis of poly[bis(p-tolylamino)]phosphazene has been studied in methylene chloride solution. The main reactions observed were chain scission and crosslinking. The dissociation into radicals of polyphosphazene is proposed as the primary act of the photolysis. This has been substantiated by the results of the photolysis carried out in the presence of both radical scavengers and some benzophenones as sensitizers.     

Preparation of Coaxial-Electrospun Poly[bis(p-methylphenoxy)]phosphazene Nanofiber Membrane for Enzyme Immobilization

A core/sheath nanofiber membrane with poly[bis(p-methylphenoxy)]phosphazene (PMPPh) as the sheath and easily spinnable polyacrylonitrile (PAN) as the core was prepared via a coaxial electrospinning process. Field-emission scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the nanofiber membrane. It was found that the concentration of the PAN spinning solution and the ratio of the core/sheath solution flow rates played a decisive role in the coaxial electrospinning process. In addition, the stabilized core/sheath PMPPh nanofiber membrane was investigated as a support for enzyme immobilization because of its excellent biocompatibility, high surface/volume ratio, and large porosity. Lipase from Candida rugosa was immobilized on the nanofiber membrane by adsorption. The properties of the immobilized lipase on the polyphosphazene nanofiber membrane were studied and compared with those of a PAN nanofiber membrane. The results showed that the adsorption capacity (20.4 ± 2.7 mg/g) and activity retention (63.7%) of the immobilized lipase on the polyphosphazene nanofiber membrane were higher than those on the PAN membrane.     

Oligomer-Rich Fraction from Polydisperse Sample of Poly(bis(β-phenoxyethoxy)phosphazene)

Poly[bis(β-phenoxyethoxy)phosphazene] [PBPEP] had been shown in our previous paper to be a very useful polymer for investigating the crystallization mechanism of polymers, as the crystallization rate of PBPEP is extraordinarily small when isothermally crystallized from the melt. The crystallization of the low molecular weight oligomers of PBPEP was first studied in comparison to the high molecular weight polymers. The oligomer-rich fraction was obtained by fractionation of the as-polymerized sample, which had a broad molecular weight distribution. The fractions thus obtained were characterized by solution viscometry and size exclusion chromatography. The melting temperature and the growth rate of the spherulite from the melt were investigated by differential scanning calorimetry and optical microscopy. The growth rate was one or two orders of magnitude smaller in the oligomer-rich fraction than in the other high molecular weight fractions. A collapsed spherulite appeared in the oligomer-rich fraction at high crystallization temperatures. It is speculated that in the oligomer-rich fraction there is an excess free energy due to defects in the crystal phase. This defect is considerably larger in the oligomer-rich fraction than in the other fractions because a large quantity of short length chains is present.     

Gas transport in poly[bis(trifluoroethoxy)phosphazene]

The gas transport parameters of 14 gases in poly[bis(trifluoroethoxy)phosphazene] were determined at temperatures ranging from about 12 to 45°C by the time-lag method. The phosphazene polymer demonstrated a high diffusivity; rather high crystallinity was expected, though. The permeation data determined were between polydimethylsiloxane and low-density polyethylene. The most interesting characteristic shown over the course of experimentation is that poly[bis(trifluoroethoxy)phosphazene] has significantly high solubility for CO₂, as compared to other gases. The polar side groups—i.e., the electron-withdrawing trifluoroethoxy parts—which should contribute specific interaction with CO₂, were shown to be stronger than their interaction with the polar N₂O molecule. The sorption behavior is compared with those of other rubbery polymers, while phosphazene polymer characteristics are also discussed.     

Synthesis and Characterization of Poly[bis(3-aminophenyl) diselenide] and Poly[bis(3-aminophenyl) diselenide-co-aniline]

Summary Bis(m-aminophenyl)diselenide was synthesized by diazotation of m-nitroaniline followed by incorporation of potassium selenium cyanate, and the reduction of the nitro groups by addition of tin and concentrated HCl. This dihydrochloride monomer was polymerised using ammonium persulphate in 0.25 M HCl as oxidizing agent. Copolymers of aniline with bis(m-aminophenyl)diselenide were prepared by oxidation of diselenide and aniline mixtures, at several mole ratios of aniline in the feed (f₁), with the same oxidizing agent. In the all the range of polymers analysed there are more diselenide comonomer units than aniline units. The polymer and copolymers were characterized by FTIR, elemental analysis, thermal stability and electrical conductivity, showing a high thermal stability, with a weight loss of 10% at 400 °C and there is an important effect of groups diselenide on the electrical properties, because conductivities are highly modified when the substitution is in m-position in the aniline ring. Therefore, it is necessary to add a high mole ratio of aniline in the feed to obtain copolymers with conductivities within the semi-conduction range.     

Degradation of poly[bis(ethylamino)phosphazene] in aqueous solution

Three polymers of poly[bis(ethylamino)phosphazene] (PBEAP) containing different amounts of the residual P–Cl moieties, which had been hydrolyzed into P OH in the following sample purification processes, were prepared by substitution of the chlorines on poly(dichlorophosphazene) with ethylamine. Only the polymer which had the highest side-chain content of ethylamino groups (ca. 93°_o) had a film-forming ability and a crystalline nature. The hydrolytic degradation of PBEAP in acidic solutions was investigated using the solution viscosity data obtained as a function of standing time. Acetic acid, 0.5 and 1N, pure acetic acid, and 2.2.2-trifluoroethanol were used as solvents. The degradation was composed of random breaking processes along the polymer chain, especially at the-N=P(OH)₂-and-N=P(OH)(NHC₂H₅)-units, and an unzippering-like breaking process which was started at the chain ends produced by the former random breaking. The random breaking caused an abrupt decrease in viscosity at the beginning of the degradation, and on the contrary, the unzippering-like breaking appeared as a gradual decrease in viscosity at the later stages of degradation. The total rate of degradation depended on the concentration of the ethylamino groups.     

Characteristics of phase transitions in poly[bis(trifluoroethoxy)phosphazene]

The data on phase transitions in bis(trifluoroethoxy)phosphazene were examined and generalized. Their nature was determined and the mechanism of the transitions was described. Schemes were proposed for the phase transitions that take into account the conditions of fabrication and thermal history of the samples. Translated from Khimicheskie Volokna, No. 5, pp. 24–27, September–October, 1998.     

The atomistic simulation of the gas permeability of poly(organophosphazenes). Part 2. Poly[bis(2,2,2-trifluoroethoxy)phosphazene]

Self-diffusion and sorption of seven gases (He, H₂, O₂, N₂, CH₄, CO₂, and Xe) in poly[bis(2,2,2-trifluoroethoxy)phosphazene] (PTFEP) have been investigated by molecular dynamics and Grand Canonical Monte Carlo (GCMC) simulations of two amorphous cells and an α-orthorhombic crystalline supercell. In the case of MD simulation of diffusion coefficients, values obtained for both amorphous and crystalline PTFEP are similar and comparable to experimental values reported for semicrystalline samples. These results indicate that gas diffusion is unrestricted in the crystalline state of PTFEP as has been reported for poly(4-methyl-1-pentene) (PMP) and, more recently, for a crystalline form of syndiotactic polystyrene (sPS).In contrast to both PMP and sPS that have low-density crystalline forms, only He exhibits any solubility in the α-orthorhombic crystalline cells of PTFEP during simulation. In addition, values of the solubility coefficients obtained from simulation of the amorphous cells are three to five times larger than would be expected by extrapolating values reported for semicrystalline samples to 100% amorphous content. These results suggest that while the crystalline domains do not restrict gas diffusivity in PTFEP, they significantly reduce gas solubility in semicrystalline PTFEP through the reduction of amorphous content and through some additional effect of the crystallites on amorphous-phase solubility, possibly through chain immobilization of the amorphous phase. Similar solubility behavior has been suggested for polyethylene on the basis of recent simulation studies.As reported in a prior communication, the solubility of CO₂ in PTFEP is very high compared to other gases due to a weak quadrupole-dipole interaction between CO₂ and the trifluoroethoxy group of PTFEP. As a result, the solubility coefficients of CO₂ obtained from GCMC simulation of the amorphous cells and from permeability measurements of semicrystalline samples are both larger than predicted by a simple correlation of gas solubility coefficients with the Lennard-Jones potential well parameter, ε/k, of other gases as proposed by Teplyakov and others. A modified form of this correlation that includes a Flory interaction term is shown to fit all gas solubility data for this polymer including that of CO₂.     

Pervaporation of organic solvents by poly[bis(2,2,2-trifluoroethoxy) phosphazene] membrane

The permeation and pervaporation behaviour of water and several organic solvents through poly[bis(2,2,2-trifluoroethoxy)phosphazene] (PBFP) membrane have been investigated in the temperature range from 42 to 80°C. The steady-state permeation fluxes of the solvents increased in the following order: methanol > ethanol > benzene > water > cyclohexane. An Arrhenius plot of permeation flux of water suddenly changed in its gradient at about 66–70°C, which corresponds closely to the T(1) transition temperature (75°C) of PBFP studied. Interestingly, in the pervaporation of water-methanol mixtures, methanol permeated more rapidly through the membrane than did water; however, the pervaporation of water-ethanol mixtures showed poor permselectivties. In the case of an athermal mixture of methanol and ethanol, the fluxes of methanol and ethanol indicated convex and concave curves, respectively, to the axis of methanol concentration; thus the separation characteristics of this system were slightly better than those of a simple distillation technique. The pervaporation of benzene-cyclohexane mixtures showed excellent permselectivty enrichment in benzene resulting in a separation factor of 12.     

Novel blends of poly[bis(glycine ethyl ester) phosphazene] and polyesters or polyanhydrides: compatibility and degradation characteristics in vitro

Poly[bis(glycine ethyl ester)phosphazene] (PGP) was blended with poly(D ,L ‐lactide) (PLA), poly(D ,L ‐lactide‐co‐glycolide) (80:20 by mole) (PLGA), poly(sebacic anhydride) (PSA) and poly(sebacic anhydride‐co‐trimellitylimidoglycine)‐block‐poly(ethylene glycol) (30:50:20 by mole) (PSTP) in various ratios using a solvent‐mixing technique. The compatibility of these blends has been evaluated by DSC, FTIR and phase contrast microscopy. The results indicated that PGP is completely incompatible with PLA, but partially compatible with PLGA and PSTP, which may be attributed to a hydrogen bonding effect. Degradation experiments have been conducted in distilled water at 37 °C and show that the blend degradation rate can be regulated by adjusting the PLGA or PSTP content of the blends. PGP/PLGA (70:30 by wt) slabs took 120 days to disappear completely, while PGP/PSTP (70:30 by wt) slabs needed only 20 days. These findings suggest that blends of PGP and PLGA or PSTP may be used as matrices for drug controlled release and for other potential biomedical applications. © 2000 Society of Chemical Industry     

Synthesis and Characterization of Poly[bis(ethyl salicylate)phosphazenes] and Poly[bis(ethyl salicylate diethylamino)phosphazenes] and Their Hydrolytic Degradation

The polydichlorophosphazenes were synthesized from hexachlorocyclotriphosphazenes by ring opening polymerization in the presence of AlCl₃ as a catalyst. Poly[bis(ethyl salicylate)phosphazenes] (PESP) and poly[bis(ethyl salicylate diethylamino)phosphazenes] (PESDEAP) were synthesized via macromolecular substitution reactions using ethyl salicylate and (or) diethylamine as side groups. The synthesis results were proved by nuclear magnetic resonance (¹H NMR, and ³¹P NMR) and gel permeation chromatography. In addition, the hydrolytic degradation of PESP and PESDEAP was investigated at constant temperature in neutral medium.     

Poly[N-(2-hydroxypropyl)methacrylamide]. IV. Heterogeneous polymerization

Kinetics of radical heterogeneous polymerization of N-(2-hydroxypropyl)methacrylamide was studied in acetone at 55°C. The values of reaction order with respect to the monomer (1.6) and to the initiator (0.5) indicate a bimolecular termination and degradative transfer during the chain growth. The over-all rate constant of polymerization was found to be 5.6.10-4. Addition of a small amount of a solvent (methanol) to the polymerization mixture led to an increased polymerization rate and increased molecular weight of the resulting polymer, but a higher amount of the solvent brought about a decrease of both characteristics. The Occurence of maxima on the dependences of R_p, as well as M?_w on the monomer concentration was interpreted in terms of the classical Bamford and Jenkins theory.     

Synthesis and Characterization of Poly[bis(resorcinol monobenzoate) phosphazenes] and Poly[bis(resorcinol monobenzoate diethylamino) phosphazenes] and Their Self Assembly Behaviors

Poly[bis(resorcinol monobenzoate)phosphazenes] (PRMBP) and poly[bis(resorcinol monoben- zoate diethylamino)phosphazenes] (PRMBDEAP) were synthesized in two steps. In the first step, polydichlorophosphazenes (PDCP) were synthesized from hexachlorocyclotriphosphazenes (HCCP) via ring opening polymerization in the presence of AlCl₃ as a catalyst. In the second step, the chlorine atoms in PDCP were replaced with resorcinol monobenzoate and (or) diethylamine in a macromolecular substitution reaction. The structures of the polymers were elucidated by ¹H NMR, ³¹P NMR, and GPC. In addition, the self assembly behaviors of PRMBP and PRMBDEAP were investigated in different solvent using optical microscopy and SEM techniques. The SEM images showed that PRMBDEAP self assembled into star-like dendrimers comprising of open ended tubular arms.     

Untersuchungen über Poly(arylenvinylen)e. XVII [1]. Poly(1,4-phenylen-1,2-diphenylvinylen)

Investigations on Poly (arylenevinylene)s. XVII. Poly(1,4-phenylene-1,2-diphenylvinylene) Soluble poly(1,4-phenylene-1,2-diphenylvinylene) of high molecular mass is synthesized by dehalogenation-polycondensation reaction of 1,4-bis(phenyldichloromethyl)benzene with water-free chromous acetate in a mixture of benzene/dimethylformamide. The absorption and photoconductivity spectra as well as a number of thermal (TGA, Tg) and electrical properties are described. Both the similarity of model reactions as the dehalogenation of diphenyldichloromethane to tetraphenylethylene and the dependence of the molecular mass on the quantity of the reducing agent lead to the conclusion that the above-mentioned polycondensation reaction takes place as a step-growth mechanism.     

Spherulitic crystallization in poly(bis(trifluoroethoxy)phosphazene), PBFP

Spherulite formation in poly(bis(trifluoroethoxy)phosphazene) has been investigated from the melt and from solution over a relatively wide crystallization and annealing range. Three polymorphic forms and one mesoform is found in this polymer. Several of these crystal modifications coexist in amounts which depend upon the crystallization conditions. Negatively birefringent spherulites increase in birefringence slightly upon being heated through the thermotropic T(1) transition. This change involves the formation of a chain extended morphology from a chain folded one. Microbeam X-ray analysis made within the spherulite shows that the unit cell [a] direction is along the spherulite radius while the [c] chain direction lies transverse to the spherulite radius. Moreover, below T(1) it has been established that the X-ray long period is invariant with annealing time and temperature, and above T(1) the periodicity disappears, or cannot be recorded. Whenever heating or cooling occurs through T(1), the spherulite birefringence appears to be invariant after initially heating through T(1). However, a substantial volume change (by dilatomery) of 6% occurs through T(1) and this is consistent with a change in crystal structure from a 3D orthorhombic structure below, to a 2D hexagonal form above T(1). From the molten state the transformation occurs rapidly from isotropic to the 2D form of the mesostate, not far below T_m. The 2D hexagonal form reverts to 3D chain extended orthorhombic on cooling below T(1). This stable chain extended morphology also arises whenever PBFP is melted and then cooled below T(1). All transformations from the isotropic melt or the folded chain conformation must pass through the mesophase. All specimens are friable upon cooling below T(1), whereas the solution case spherulitic polymer film is ductile here.     

Sorption and permeation properties of water and ethanol vapors in poly[bis(trifluoroethoxy)phosphazene] (PTFEP) membranes

The permeability and solubility for water and ethanol in PTFEP membranes were determined experimentally, and the data were analyzed by the solution-diffusion model. The permeability for water and ethanol ranged from several hundreds to several thousands Barrers, and they increased exponentially with the vapor activity and increased with temperature. At the same temperature and vapor activity, the permeability ratio between water and ethanol ranged from 5.7 to 2.3, and it decreased as the vapor activity increased. The sorption isotherms for water and ethanol were fitted by the Henry’s law relationship. The solubility decreased as the temperature increased so that the heat of sorption for both water and ethanol was negative. The solubility for water was more than twice the solubility for ethanol. The solubility seems to be inversely proportional to the molecular size of the penetrants in such a system. The solubility ratio between water and ethanol is smaller than their molecular volume ratio possibly due to the slightly stronger nonpolar interaction and the higher degree of plasticization in the ethanol-polymer system. The diffusivity for water and ethanol ranged from 10⁻⁸ to 10⁻⁷ cm²/s, and the values for water were larger than those for ethanol at the same temperature and vapor activity. The diffusivity for water and ethanol also increased exponentially with the vapor activity. The diffusivities for water and ethanol increased with temperature and their activation energies of diffusion were very similar possibly due to the same energy characteristic of polymer main chain movement.     

聚乙二醇甲醚磷腈的合成及其对粘胶纤维的阻燃改性

利用线形聚二氯磷腈(PDCP)与甲醚乙二醇钠反应,合成了聚乙二醇甲醚磷腈(PMEP);采用正交实验分析了溶剂用量、反应时间、反应物配比以及提纯方法对PMEP产率和相对分子质量的影响,优选出最佳的合成工艺条件;利用红外光谱、核磁共振磷谱、差示扫描量热法等手段对合成产物进行了表征;将PMEP与粘胶纺丝原液共混纺丝制备了PMEP共混改性粘胶纤维,初步探讨了PMEP对粘胶纤维的阻燃效果。结果表明:相转变法能减少提纯过程中产物的流失,且能减少提纯分离的周期;PMEP的最佳合成工艺为PDCP与甲醚乙二醇钠摩尔比1.0∶3.0,四氢呋喃溶剂25 m L,反应温度68℃,反应时间10 h;PMEP共混改性粘胶纤维具有良好的阻燃效果,PMEP质量分数为15%时,其阻燃改性粘胶纤维极限氧指数达33%。     

Molecular dynamics simulations of polyphosphazenes: poly[bis(chloro)phosphazene][NPCl2] n

Suitable parameter sets for the CHARMm force field were derived for the structural units in polychlorophosphazene [P=N, P N, P Cl] using the Dinur Hagler energy second derivative procedure based on quantum mechanical SCI calculations using the 6–31G^* basis set. To validate the reliability of the parameter set, structural results obtained with CHARMm for the adopted model compounds (OP₂NCl₅ and OP₃N₂Cl₅) were compared with those derived fromab initio quantum mechanics using the 6–31G^* basis set. Application of molecular dynamics (MD) simulations in combinatioin with the available X-ray diffraction data provided structural and conformational information on the polymer. The calculation made using the periodic boundary conditions (PBC) agree well with the polychlorophosphazene ordered in a monoclinic unit cell (a=5.98,b=12.99,c=4.92 A; β=111.7). This model was stabilized mainly by the image atoms contribution to the electrostatic energy term and had aquasi-planar conformation of the backbone chain (glide symmetry). The MD calculations also provided evidence that the difference between single and double PN bonds is less marked than that measured experimentally. This result is, however, in agreement with more recent and accurate X-ray studies on poly(methylphosphazene). Validation of the polymer model provided a complete picture, otherwise experimentally inaccessible, of the internal fluctuations of the polymeric chains.