Heterochain Polymer Research Articles

Heterochain polymer carbon modified transition metal composites for fabricating high energy-density supercapacitors

Although transition metals have special electronic structures and high theoretical capacitance, their low conductivity and structural instability greatly limit their practical applications. In this work, a heterochain polymer PZS containing C, N, P, S, O was used as a carbon precursor containing heteroatoms, and Ni(HCO3)2 nanoparticles were grown in situ on its surface. After calcination, a nanocage shaped PZSC/NiO (+) was acquired with large specific capacity (188 mAh g−1). Meanwhile, utilizing the adjustable pore size, sufficient surface area, and easy ion introduction of MOFs, PZS coated on the surface of CoFe-MOF was calcined to prepare a stalactite like Co3Fe4(PO4)6/PZSC (-) with expected specific capacity (114.2 mAh g−1). The assembled PZSC/NiO (+) // Co3Fe4(PO4)6/PZSC (-) supercapacitor presents an extremely high energy-density and excellent cycling stability (54.6 Wh kg−1, 93 %, 10,000 r), as well as a high specific capacity (68.5 mAh g−1).

4D Printing of Shape‐Memory Semi‐Interpenetrating Polymer Networks Based On Aromatic Heterochain Polymers

AbstractMost of the presently known thermosensitive shape‐memory polymers suitable for 4D printing have insufficient mechanical strength and thermal stability that restricts their potential areas of application. Here, new photosensitive compositions (PSCs) based on aromatic heterochain polymers – poly‐N,N′‐(m‐phenylene)isophthalamide (MPA) or poly‐2,2′‐(p‐oxydiphenylene)‐5,5′‐dibenzimidazole (OPBI) – for DLP printing are proposed. Thermal post‐curing and supercritical carbon dioxide (scCO2) are used for post‐processing of the structures. During the scCO2 treatment the removal of unreacted monomeric component (N,N‐dimethylacrylamide) and its uncrosslinked oligomers is accompanied by the preservation of the initial degree of crosslinking. The more stable shrinkage is observed for the combined post‐processing method (T°+scCO2) in the case of OPBI‐PSC and after the heat treatment for MPA‐PSC specimens. The method of post‐processing and the nature of the heterochain polymer strongly affect the mechanical properties and thermal resistance of the structures. The tensile strength has the maximum value after the thermal post‐treatment (101.1 ± 7.1 and 78.4 ± 5.1 MPa of OPBI‐PSC and MPA‐PSC, respectively). The intense destruction of the materials is observed at 393 and 408 °C for MPA‐PSC and OPBI‐PSC, respectively. Moreover, the 4D‐printed structures exhibit excellent shape memory performance at transition temperatures >100 °C, thus have a great potential for the use in aerospace, robotics, sensorics.

Study of the Influence of Magnetite Nanoparticles Supported on Thermally Reduced Graphene Oxide as Filler on the Mechanical and Magnetic Properties of Polypropylene and Polylactic Acid Nanocomposites.

A study addressed to develop new recyclable and/or biodegradable magnetic polymeric materials is reported. The selected matrices were polypropylene (PP) and poly (lactic acid) (PLA). As known, PP corresponds to a non-polar homo-chain polymer and a commodity, while PLA is a biodegradable polar hetero-chain polymer. To obtain the magnetic nanocomposites, magnetite supported on thermally reduced graphene oxide (TrGO:Fe3O4 nanomaterial) to these polymer matrices was added. The TrGO:Fe3O4 nanomaterials were obtained by a co-precipitation method using two types of TrGO obtained by the reduction at 600 °C and 1000 °C of graphite oxide. Two ratios of 2.5:1 and 9.6:1 of the magnetite precursor (FeCl3) and TrGO were used to produce these nanomaterials. Consequently, four types of nanomaterials were obtained and characterized. Nanocomposites were obtained using these nanomaterials as filler by melt mixer method in polypropylene (PP) or polylactic acid (PLA) matrix, the filler contents were 3, 5, and 7 wt.%. Results showed that TrGO600-based nanomaterials presented higher coercivity (Hc = 8.5 Oe) at 9.6:1 ratio than TrGO1000-based nanomaterials (Hc = 4.2 Oe). PLA and PP nanocomposites containing 7 wt.% of filler presented coercivity of 3.7 and 5.3 Oe, respectively. Theoretical models were used to analyze some relevant experimental results of the nanocomposites such as mechanical and magnetic properties.

Structurally designed heterochain polymer derived porous carbons with high surface area for high-performance supercapacitors

Polyphosphazenes are considered as ideal precursors for nitrogen and/or phosphorus doped porous carbons for supercapacitor electrodes with high performances due to high phosphorus and nitrogen atoms content in their backbones. By adjusting the structure of the carbon-rich groups connected to each skeletal phosphorus atom, the structure of the corresponding carbons can effectively be tailored with appropriate content of heteroatoms and pores. Herein, we synthesized poly(naphthoxy/trifluoroethoxy)phosphazenes (PNTFPs) with different ratios of the two side groups. We envision that naphthoxylic side groups serve as “carbon source”, whereas trifluoroethoxylic side groups serve as “gas expansion agent” during processing heteroatoms-doped porous carbons. By controlling the carbonization temperature and the ratio of the two side groups on PNTFP, we have prepared nitrogen-doped porous carbons with a specific surface area of 2593 m2/g, and atomic nitrogen contents of 4.16%. The as-prepared material own specific capacitance up to 409F/g at current density of 0.1 A/g in a two-electrode system (542F/g at 0.1 A/g in three-electrode system) with capability of 259F/g at 20 A/g.

Features of Structural Transformations and Properties of Polycaproamide Modified with Polyfluorated Alcohol Immobilized on Montmorillonite

The effect of 1,1,9-trihydroperfluorononanol-1 immobilized on montmorillonite nanoclay on the nature of structural transformations and the properties of polycaproamide composites was studied. Using the methods of electron, atomic force microscopy and differential scanning calorimetry, we established the features of changing the diameter and height of spherulites in non-oriented films of this heterochain polymer, as well as the reorganization of its polymorphic composition due to the introduction of a fluorine-containing modifier. The stabilizing effect of the additive used on the mechanical properties and thermo-oxidative stability is shown.

Reducing the Combustibility of Polycaproamide Using a Mixture of Polyelemental Flame Retardants

A study was carried out on the effect of 1,1,9-trihydroperfluoro-1-nonanol immobilized on montmorillonite nanoclay in combination with decabromodiphenyl oxide, perfluorinated antimony alcoholate, and diantimony trioxide on the combustibility of polycaproamide. X-ray structural analysis and differential scanning calorimetry were used to establish a relationship between the combustion resistance of the heterochain polymer and its morphology attributed to reorganization of the amorphouscrystalline structure due to the effect of the introduced combustion retarder, which causes redistribution of the fractions of the α- and γ-crystalline forms in the polymorphous composition of the polycaproamide, leading to a fluorine-containing material with reduced combustibility.

Arc Atomic Emission Analysis of Rare Earth Metals and Their Oxides with Preliminary Sorption Concentration of Impurities

This work investigates in analytical capacities of arc atomic emission analysis (AAEA) in determination of As, Bi, Sb, Cu, and Te in rare earth metals (REM) and their oxides after preliminary group concentration using S,N-containing heterochain polymer sorbent. The investigations have been carried out using a Grand-Extra high-resolution spectrometer developed by VMK-Optoelektronika (Russia). Sorption kinetics and impurity extraction rate as a function of solution acidity have been studied for a selection of conditions of sorption concentration. Aiming at optimization of arc atomic emission detection of As, Bi, Sb, Cu, and Te, various flowcharts of their sorption concentration and subsequent treatment of obtained concentrated product have been considered with addition of a collector at various sorption stages. Powdered graphite has been used in this work as a collector in analysis of rare earth oxides, which is attributed to the relative simplicity of its emission spectrum and versatility. Analytical conditions and spectrometer parameters affecting the analytical signal (sample weight and composition, shape and size of electrodes, current intensity and operating mode of generator, interelectrode distance, wavelengths of analytical lines) have been selected. The evaporation curves of detected impurities have been analyzed, and the exposure time of As, Bi, Sb, Cu, and Te in the obtained sorption concentrate has been determined. Accuracy of the results has been evaluated using reference samples and by comparisons between methods. The results have been used for development of arc chemical atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium, and their oxides in the concentration range of n × (10–5–10–2) wt %.

X-Ray Structure and PMR Spectra of Polycaproamide Modified by a Polyfluorinated Alcohol

Effects on polycaproamide structure of a polyfluorinated alcohol immobilized on montmorillonite clay nanoparticles were studied using x-ray structure analysis and broad-line PMR spectroscopy. An exfoliated composite formed and caused the crystal and molecular structures of this heterochain polymer to reorganize. A composite based on the polyfluorinated alcohol changed the mobility of macromolecular chain segments and increased the fraction of planar trans-conformations.

Dc arc emission analysis of rare earth metals and their oxides with sorption preconcentration of impurities

The analytical capabilities of arc atomic emission determination of As, Bi, Sb, Cu, Te in rare earth metals (REM) and their oxides after preparatory group concentration using S,N-containing heterochain polymer sorbent are studied on a high-resolution spectrometer “Grand- Extra” (“WMC-Optoelectron-ics” company, Russia). Sorption kinetics and dependence of the degree of the impurity extraction on the solution acidity are analyzed to specify conditions of sorption concentration. To optimize the procedure of arc atomic emission determination of As, Bi, Sb, Cu, and Te various schemes of their sorption preconcentration and subsequent processing of the resulted concentrate with the addition of a collector at different stages of the sorption process have been considered. Graphite powder is used as a collector in analysis of rare earth oxides due to universality and relative simplicity of the emission spectrum. Conditions of analysis and parameters of the spectrometer that affect the analytical signal (mass and composition of the sample, shape and size of the electrodes, current intensity and generator operation mode, interelectrode spacing, wavelengths of the analytical lines) are chosen. The evaporation curves of the determinable impurities were studied and the exposure time of As, Bi, Sb, Cu, and Te in the resulted sorption concentrate was determined. Correctness of the obtained results was evaluated using standard samples of the composition and in comparisons between methods. The results of the study are used to develop a method of arc chemical-atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium and their oxides in a concentration range of n x (10-2 - 10-5) wt.%.

Fluorine-Containing Polyamide Composites with Reduced Combustibility

In this paper, we studied the modifying effect of montmorillonite modified with polyfluorinated telomeric alcohols and of antimony(III) polyfluoroalkoxide on the structure and properties of polymer composites based on polyamide 6. The nature of the effect of the modifier on the state of amorphous and crystalline phases in the supramolecular structure of this heterochain polymer was determined by X-ray diffraction analysis and microscopy. The effect of reducing combustibility due to the introduction of a fluorine-containing modifier is considered.

UV‐laser formation of 3D structures based on thermally stable heterochain polymers

ABSTRACTA new approach to making a photopolymeric composition was first elaborated in this work based on the use of poly‐N,N′‐(m‐phenylene)isophtalamide as the heterochain polymer matrix together with 4,4′‐diphenyl oxide diacrylamide as the crosslinking agent. Reproducible three‐dimensional (3D) objects have been formed using a laser stereolithograph completed with a laser with wavelength of 405 nm. According to the thermogravimetric analysis, the thermal stability of the formed objects could be changed through a control from 260 to 405 °C. Moreover, it was proven that the tensile strength of samples of the crosslinked films reached 90.1 ± 3.2 MPa at the elongation at break of 12.4 ± 2.3%, depending on the forming parameters of such samples. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46463.

Relationship between the morphology and combustibility of fluorinated polyamide composites

The effect that polyfluorinated alcohols immobilized on montmorillonite support exert on structuralmorphological characteristics and combustibility of polymer composites was studied with 1,1,9-trihydroperfluoro- 1-nonanol as example. The relationship between the flame resistance of this heterochain polymer and its morphology was revealed by X-ray diffraction analysis, electron microscopy, DSC, and Fourier IR spectroscopy. This relationship is associated with the reorganization of the crystal and molecular structure under the influence of fluorinated organoclay, ensuring increased degree of crystallinity and redistribution of the fractions of α- and γ-crystalline forms in the polymorphic composition of polycaprolactam, making its supramolecular structure more perfect, and favoring preparation of a fluorinated material of decreased combustibility.

A Newly Designed Dual‐Functional Epoxy Monomer for Preparation of Fishbone‐Shaped Heterochain Polymer with a High Damping Property at Low Temperature

A novel high purity dual‐functional epoxy monomer, diglycidyl ether of 4,4′‐diallyl‐bisphenol‐A, is deliberately designed for the construction of a fishbone‐shaped heterochain polymer by polymerizing it with the methyl phenyl polysiloxane. Their curing reactions with Jeffamine D230 are investigated. The cured fishbone‐shaped heterochain polymer presents a wide transition range spanning over 120 °C with a peak half‐width of 62 °C. In contrast to the traditional epoxy/polysiloxane materials, the cured fishbone‐shaped heterochain polymer takes full advantage of the cooperative effect of epoxy and polysiloxane exhibiting excellent damping properties (tan δ > 0.3) at temperatures near the T g of the polysiloxane. This outstanding low‐temperature damping performance can be ascribed to the fishbone‐shaped structure of the heterochain polymer. These results provide new approach to explore high damping materials used at extremely low temperature (−125 °C). image

Separation and preconcentration of platinum-group metals from spent autocatalysts solutions using a hetero-polymeric S, N-containing sorbent and determination by high-resolution continuum source graphite furnace atomic absorption spectrometry

This paper describes the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for determination of Pt, Pd and Rh after separation and concentration by original in-house developed heterochain polymer S, N-containing sorbent. The methods of sample preparation of spent ceramic-based autocatalysts were considered, two of which were used: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7. Both methods anyway limit the direct determination of analytes by HR CS GFAAS. Using the first method it is an incomplete digestion of spent autocatalysts samples, since the precipitate is Si, and the rhodium metal dissolves with difficulty and partially passes into solution. In contrast to the first method, the second method allow to completely transfer analytes into solution, however, the background signal produced by the chemical composition of the flux, overlaps the analytical zone.It was found, that Pt, Pd and Rh contained in the spent ceramic automotive catalysts could be effectively separated and concentrated by heterochain polymer S, N-containing sorbent, which has high sorption capacity, selectivity and resistant to dilute acids. The chosen HR CS GFAAS analysis conditions enable us to determine Pt, Pd and Rh with good metrological characteristics. The concentrations of Pt, Pd and Rh in two samples of automobile exhaust catalysts were found in range of 0.00015–0.00050; 0.170–0.189; 0.0180–0.0210wt%, respectively. The relative standard deviation obtained by HR CS GFAAS was not more than 5%. Limits of detection by HR CS GFAAS achieved were 6.2·10−6wt% for Pt, 1.8·10−6wt% for Pd, and 3.4·10−6wt% for Rh. Limits of determination achieved by HR CS GFAAS were 1.1·10−5wt% for Pt, 6.9·10−5wt% for Pd, and 8.3·10−5wt% for Rh.To control the accuracy of PGM in sorption concentrates by HR CS GFAAS method, it was appropriate to conduct an inter-method comparative experiment. The researches on the application of atomic-emission spectroscopy method with inductively coupled plasma as a comparative method were conducted. In addition, the trueness control of the obtained results is confirmed by added-found method.

Platinum overview 2001

This paper describes the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for determination of Pt, Pd and Rh after separation and concentration by original in-house developed heterochain polymer S, N-containing sorbent. The methods of sample preparation of spent ceramic-based autocatalysts were considered, two of which were used: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7. Both methods anyway limit the direct determination of analytes by HR CS GFAAS. Using the first method it is an incomplete digestion of spent autocatalysts samples, since the precipitate is Si, and the rhodium metal dissolves with difficulty and partially passes into solution. In contrast to the first method, the second method allow to completely transfer analytes into solution, however, the background signal produced by the chemical composition of the flux, overlaps the analytical zone.It was found, that Pt, Pd and Rh contained in the spent ceramic automotive catalysts could be effectively separated and concentrated by heterochain polymer S, N-containing sorbent, which has high sorption capacity, selectivity and resistant to dilute acids. The chosen HR CS GFAAS analysis conditions enable us to determine Pt, Pd and Rh with good metrological characteristics. The concentrations of Pt, Pd and Rh in two samples of automobile exhaust catalysts were found in range of 0.00015–0.00050; 0.170–0.189; 0.0180–0.0210 wt%, respectively. The relative standard deviation obtained by HR CS GFAAS was not more than 5%. Limits of detection by HR CS GFAAS achieved were 6.2·10−6 wt% for Pt, 1.8·10−6 wt% for Pd, and 3.4·10−6 wt% for Rh. Limits of determination achieved by HR CS GFAAS were 1.1·10−5 wt% for Pt, 6.9·10−5 wt% for Pd, and 8.3·10−5 wt% for Rh.To control the accuracy of PGM in sorption concentrates by HR CS GFAAS method, it was appropriate to conduct an inter-method comparative experiment. The researches on the application of atomic-emission spectroscopy method with inductively coupled plasma as a comparative method were conducted. In addition, the trueness control of the obtained results is confirmed by added-found method.

Calculation of excess entropy of mixing of low molecular weight compounds with melts of heterochain polymeric and dimeric compounds and the entropy contribution of macromolecules in the liquid

The difference between the molar excess entropies of mixing, ΔΔS i- j ∞, of low molecular weight substances at their limiting dilution in polymer and dimer melts has been determined from the vapour-liquid equilibrium data on linear heterochain polymer or dimer-low molecular weight organic substance systems over a wide temperature range. Equations were obtained for calculating ΔΔS i- j ∞ in systems, weakly and strongly associated by hydrogen bonding in the polymer. A concept for the entropy contribution of macromolecules in the liquid was formulated. In the framework of the theory of corresponding states, the parameters of the entropic contribution of macromolecules in melts and the values of some compounds were calculated which agree satisfactorily with the experiment.

Study of solvation of alkali cations with poly(ethylene oxide)

The interaction of sodium, potassium and caesium salts with poly(ethylene oxide) in nitromethane is considered as a model for solvation of alkali counterions with a heterochain polymer during the anionic polymerization of heterocycles. The methods of 23Na and 133Cs n.m.r. and of conductometry sensitive towards the state of the cation have been used for studying the equilibria. It has been shown that poly(ethylene oxide) binds cations much more strongly than monomeric cyclic ethers, a solvation shell being formed involving several (6–12) oxygen atoms of the same macromolecule. The equilibrium constants of the formation of solvate complexes have been evaluated; they increase with increasing chain length and decreasing cation radius. The mechanism of interactions and their role in the processes of anionic polymerization are discussed.

The hydrolytic stability of some polyimides

In most papers dealing with the heat resistance of polymers the study of thermal stability generally reduces to thermogravimetric analysis in an inert atmosphere (thermal degradation) or in air (thermal-oxidative degradation). In these circumtances it is often not possible to follow certain degradative processes that do not involve substantial change in the weight of the polymer. At the same time many new polymers that are highly heat resistant as far as thermogravimetric analysis is concerned, are condensation polymers, the hetero-atom linkages of which are often less resistant to hydrolysis than to heat and thermal stability of these can be limited by their resistance to ionic, rather than to radical influences. The ionic degradation process of major importance is hydrolysis, which causes change in the chemical structure of the heterochain polymer, reduction in its molecular weight and consequent change in its physicomechanical properties.

Polyketoamines as a new type of heterochain polymer

Polyketoamines as a new type of heterochain polymer

Polyketosulphides as a new type of heterochain polymer

Polyketosulphides as a new type of heterochain polymer