Thermal behavior of zinc γ-zirconium phosphate intercalation compounds

Summary The layered ion-exchangers γ-zirconium phosphate and γ-zirconium phosphate containing intercalated diamines, obtained by exchanging zinc ions, have been synthesized and characterized. Zinc ions are able to form coordination compounds between the layers of the host matrix and consequently form zinc complexes formed in situ. The zinc ions uptake, the thermal behavior and the structural characterization of the compounds obtained have also been examined. The thermal stability and X-ray spectra of these compounds depend on the type of isomeric diamine precursor. The zinc fully exchanged γ-zirconium phosphate is able to form ZnS particles in the host matrix. The X-ray spectra of this obtained material matched those of the initial γ-zirconium phosphate precursor.     

Synthesis and characterization of sol-gel zirconium phosphate with template surfactants by different methods

Long chain trimethylammonium salts can be successfully used as guest molecules to produce mesoporous layered materials when intercalated in sol-gel zirconium phosphate, an inorganic ion-exchanger. The obtained materials are very similar independently of the chain length and the synthesis method batch (B) or direct intercalation (DI). They show a good thermal stability, and a very high interlayer distance if compared with their precursor. By the thermal characterization it can be observed that the surfactant is lost in two or three steps depending on its position in the host. The layered structure with the expanded interlayer distance is maintained up to 300°C. From the IR spectra the different surfactant release models for (B) and (DI) are confirmed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal behaviour of g-zirconium phosphate intercalation compounds with template surfactants

Long chain alkylammonium cations can be exchanged into a preswelled phase of g-zirconium phosphate, a layered inorganic ion-exchanger. The derived materials are used as templates to give organic-inorganic composite materials. The cationic exchange occurs very quickly. These intercalation compounds behave in a very similar way. They are still layered and exhibit an interlayer distance d notably greater than that of its precursor whose behavior depends on the chain length. By thermal and microanalyser characterizations it can be observed that the surfactant is lost in two stages, the second one as a result of the fragmentation of the chain. The layered structure with the expanded interlayer distance is maintained up to ~350°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

γ-Zirconium and γ-Titanium Phosphates Platinum Intercalation Compound Preparation, characterization and thermal behaviour

Inorganic ion-exchangers with a layered structure such as γ-zirconium and γ-titanium phosphates, intercalated with organic diamines, are able to exchange Pt²⁺ ions to give new intercalation compounds that can be utilized in heterogeneous catalysis. The experiments performed at different temperatures (25 and 45°C), show different ion uptakes, greater at 45°C and for the materials derived from γ-zirconium phosphate. After platinum exchange, all the materials show an amorphization in the XRD if compared with their precursors. The thermal behaviour of the platinum materials is specific, depending on the exchanger used and the ligand inside the exchanger. Pt²⁺ ion has a catalytic effect on ligand elimination in the γ-zirconium phosphate platinum compounds, but not in those derived from γ-titanium. All the obtained yellow materials show a small step in the TG curves and simultaneously we have the Pt²⁺→Pt⁰ reduction: this is confirmed by XRD registered at the temperatures of the thermal effect, showing peaks at d_hkl=2.27 and 1.95 Å. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation and thermal decomposition study of pyridinedicarboxylate intercalated layered double hydroxides

Supramolecular 2,3- and 2,5-pyridinedicarboxylate (PDC) intercalated ZnAl-layered double hydroxides (2,3- and 2,5-PDC–ZnAl–LDHs) have been prepared by ion exchange method. The structure and composition of the intercalated materials have been studied by X-ray diffraction (XRD) and inductively coupled plasma emission spectroscopy (ICP). The study indicates that the 2,3-PDC and 2,5-PDC anions are accommodated as interdigitated bilayer and monolayer arrangement respectively between the sheets of LDHs. Furthermore, their thermal decomposition processes were studied by the use of in situ high temperature X-ray diffraction (HT-XRD), and the combined technique of thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS) under N2 atmosphere. Based on the comparison study on the temperatures of both decarboxylation and complete decomposition of interlayer PDC, it can be concluded that 2,5-PDC–ZnAl–LDHs has higher thermal stability than that of 2,3-PDC–ZnAl–LDHs.     

Preparation,combustion, and thermal behavior of UV‐cured epoxy‐based coatings containing layered double hydroxide

The bisphenol A epoxy acrylate resin (EA) containing a small amount of layered double hydroxide (LDH) was cured within seconds under UV irradiation at ambient temperature. Its microstructure was characterized by X‐ray diffraction (XRD). The combustion behavior of the coating was examined by the Microscale Combustion Calorimeter (MCC) and limiting oxygen index (LOI). The results obtained from MCC and LOI indicated that the addition of LDH into EA could decrease the peak of heat release rate (HRR) for the films and increase the LOI value of the films. Thermal behavior of the cured films was studied by thermogravimetric analysis (TGA). The results for TGA indicated that with increase in the contents of LDH, the residual char of UV‐cured films increased at 600 °C. The evolved products for UV‐cured films were characterized using thermogravimetric analysis/infrared spectrometry (TGA‐IR). It was implied that the mechanism of thermal degradation for EA0 was different from EA4. Viscoelastic property of photo‐cured hybrid materials was evaluated by dynamic‐mechanical analysis. The effect of LDH on the properties of UV‐curable films was critically evaluated in this paper. Copyright © 2010 John Wiley & Sons, Ltd.     

New 12-tungstophosphate-based organic-inorganic hybrid. Synthesis, spectroscopic characterization, X-ray determination and thermal behavior

12-Tungstophosphate-based organic/inorganic hybrid, [HNMPA]₃[O₄₀PW₁₂].0.5NMPA.₂H₂O (NMPA = N-methylpropionamide) was synthesized and characterized by IR, UV-Vis, ¹H, ¹³C and ³¹P NMR spectroscopies, elemental analysis, TGA, DTA and single crystal X-ray determination. Full decomposition of the hybrid leads to WO₃ powder was studied by IR, SEM and XRD.     

一元-二元羧酸镧复合热稳定剂的合成与表征

以常见的一元羧酸和二元羧酸以及硝酸镧为原料,探讨了一元-二元羧酸镧的合成条件,制备了一系列一元-二元羧酸镧复合热稳定剂产品。通过刚果红试纸法和转矩流变仪法对产品的性能进行了表征,并通过红外光谱对产品的结构进行了表征。结果表明:一元-二元羧酸镧的最优合成条件为一元酸:二元酸=1.25:1,反应温度为70℃,保温时间为50min。最优产品对PVC的动态热稳定性可达1420s。     

Theoretical model and experimental study of pore growth during thermal expansion of graphite intercalation compounds

Summary A new technique, which allows one to simultaneously follow the mass and volume of graphite intercalation compounds (GICs) during thermal transformation into expanded graphite, was developed. This enabled us to elucidate the mechanism for the thermal expansion of GICs and formulate a quantitative model for the process. Effective activation parameters of the thermal decomposition of new GICs were obtained by using non-isothermal kinetics procedure. Thermal decomposition was described as a break of intermolecular bonds followed by diffusion.     

Zinc ions and zinc sulfide particles in sol-gel zirconium phosphate synthesis, thermal behavior and X-ray characterization

Zinc ions can be exchanged in sol-gel zirconium phosphate by using the batch or hydrothermal method. The zinc materials obtained that undergo thermal treatment after complete dehydration, can rehydrate fully or partially depending on whether half or all the zinc ions are exchanged. At high temperature syntherization is evident. By flowing sulfide acid over the zinc forms, zinc sulfide particles are formed and their amount depends on the length of time of the gas flow and on the state of hydration of the original material. This is not the case in the half exchanged zinc zirconium phosphate material. The decomposition temperature of the ZnS particles depends on their position in the exchanger: whether on the surface or between the layers of the host matrix. The XRD patterns of the materials obtained are similar to those of the sol-gel zirconium phosphate. The presence of ZnS particles is evident.     

Synthesis,crystal structure,and thermal behavior of dimethylgold(III) acetate

A dimethylgold(III) compound with an acetate fragment [(CH₃)₂AuOCOCH₃]₂ has been synthesized. The complex was identified from the melting point, IR, ¹H NMR, and mass spectrometry data. The temperature dependence of saturated vapor pressure over crystals has been measured and the thermodynamic parameters of sublimation have been determined by Knudsen’s effusion method with mass spectrometric measurements of the composition of the gas phase: ΔH _subl = 100.87 kJ·mol^?1, ΔS _subl = 216.67 J·mol^?1·K^?1. The thermal behavior of the solid compound was investigated by differential thermal analysis. The compound was studied by X-ray diffraction. Crystal data for C₈H₁₈Au₂O₄: a = 12.214(5) Å, b = 14.307(3) Å, c = 7.6635(15) Å; β = 103.39(3)°, Z = 4, d _calc = 2.917 g/cm³, space group P2(1)/c, R = 0.0261. The [(CH₃)₂AuOCOCH₃]₂ dimer complex with an Au...Au distance of 2.989 Å is the structural unit. The gold atom has a square plane environment of two carbon and two oxygen atoms; the Au-O distances vary from 2.118 Å to 2.139 Å. The molecules are arranged in chains linked by van der Waals interactions.     

Synthesis,characterization, and thermal studies of cardanol-based polyphosphate esters

Polyphosphate esters were synthesized from derivatives of cardanol phosphorodichloridateates and dihydric phenols by interfacial polycondensation using a phase transfer catalyst. The polymers were characterized by IR, ¹H-, ¹³C-, and ³¹P-NMR spectroscopy, and GPC. The thermal stability and thermal degradation kinetics of the polymers were determined by thermogravimetry. The flammability of the polymers was evaluated by limiting oxygen index values. © 1993 John Wiley & Sons, Inc.     

Synthesis, Characterization, and Photophysical Properties of Materials Obtained by Co-intercalation of Chromophores into Layered Double Hydroxides

A pair of chromophores with donor‐acceptor properties, coumarin‐3‐carboxylic acid (3‐CCA) and 9‐anthracene carboxylic acid (9‐ACA), have been successfully intercalated into the layered double hydroxide (LDH), [Zn_0.66Al_0.34(OH)₂](CO₃)_0.17·0.33H₂O by an ion‐exchange method. The obtained co‐intercalation compounds were characterized by X‐ray diffraction, FTIR spectral, thermogravimetry techniques and chemical composition. The guest molecular sizes and structures were investigated utilizing an ab initio (HF/6‐31G) method by G98w. These anions were steadily arranged between the metal hydroxide layers by their carboxylate functional groups interacting with the layer plane. The photophysical properties of the obtained compounds were studied by UV‐Vis absorption and fluorescence spectroscopy. These results indicate that the confinement of the pair of chromophores, 3‐CCA and 9‐ACA, within the interlayer region of the host is in favor of guest‐host interaction and guest‐guest interaction, and that the pair of chromophores, 3‐CCA and 9‐ACA can give rise to energy transfer processes because of the characteristics of their excited states.     

Synthesis,characterization, thermal,electrical and magnetic properties of polyaniline composites with rare earth gadolinium coordination complex

Novel polyaniline/gadolinium (PANI/Gd) composites were successfully synthesized by “in‐situ” polymerization at the presence of rare earth Gd coordination complex and D‐tartaric acid (an a dopant). It is rarely to find the studies on related field to add rare earth Gd coordination complex as fillers. Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD) and scanning electron microscope (SEM) were used to examine the structure and surface appearance characterization of materials. The thermal stability performance of composites was investigated by thermogravimetry and derivative thermogravimetry (TG‐DTG). Electrochemical performance was measured by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge test. The magnetic property was investigated by physical property measurement system (PPMS). The structure and surface appearance characterization and the magnetic properties jointly demonstrate the polymerization of rare earth Gd coordination complex and PANI–D‐tartrate (DTA) not only simple physical mixing but also chemical mixing. TG‐DTG analysis suggests that thermal stability of PANI/Gd composites is higher than that of PANI–DTA. Electrochemical performance tests and SEM indicate that the composite (PANI/Gd = 3.3:1,mass ratio) has the most regular morphology and best specific capacitance. The magnetization of the composite (PANI/Gd = 3.3:1,mass ratio)is evidently smaller compared with PANI–DTA and rare earth Gd coordination complex. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis,characterization, thermal stability,conductivity, and band gaps of substitute oligo/polyamines or polyphenol

In this study, the oxidative polycondensation reaction conditions of 3,5‐dichloroaniline (DCA), 3,4,5‐trimethoxyaniline (TMA), 3,5‐bis(trifluoromethyl)aniline (BTFMA), and 4‐{[(3,5‐dichlorophenyl)imino]methyl}phenol (DCPIMP) were studied by using NaOCl oxidant in an aqueous alkaline medium between 40 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FT‐IR, Ultraviolet–visible (UV–vis), ¹H‐NMR, and ¹³C‐NMR and elemental analysis. The characterization was made by TGA–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yields of oligo‐3,5‐dichloroaniline (ODCA), poly‐3,4,5‐trimethoxy aniline (PTMA), oligo‐3,5‐bis(trifluoromethyl)aniline (OBTFMA), and poly‐4‐{[(3,5‐dichlorophenyl) imino]methyl} phenol (PDCPIMP) were found to be 98, 48, 80, and 83% in using NaOCl oxidant. According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w) and polydispersity index (PDI) values of ODCA, PTMA, and OBTFMA were found to be 2200, 3800 g mol^?1, and 1.727; 4700, 7500 g mol^?1, and 1.596; and 1690, 1950 g mol^?1, and 1.154, respectively. According to TG analysis, the weight losses of ODCA, PTMA, OBTFMA, and PDCPIMP were found to be 78.55, 54.18, 99.38, and 59.70% at 1000°C, respectively. PTMA showed higher stability against thermal decomposition. Electrical conductivity of the polymers was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical band gaps ( ) of ODCA, PTMA, OBTFMA, and PDCPIMP were calculated from their absorption edges of cyclic voltammograms. The optical band gaps (E_g) values of all compounds were calculated from UV–vis measurements. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,characterization, and thermal properties of piezoelectric polyimides

Three amorphous piezoelectric polyimides have been synthesized and characterized to analyze their utility for high‐temperature applications. The studied polyimides have been prepared from 4,4′‐oxydiphthalic anhydride and the diamines 2,4‐di(3‐aminophenoxy)benzonitrile (poly2‐4), 2,6‐bis(3‐aminophenoxy)benzonitrile (poly2‐6), and 1,3‐bis‐2‐cyano‐3‐(3‐aminophenoxy)phenoxybenzene (poly2CN). These polyimides differ in the position of the dipolar groups ? CN in the aromatic ring (poly2‐4 and poly2‐6) and in the number of these groups in the repetitive unit (poly2‐6 and poly2CN). The imidization degree has been studied by Fourier transform infrared (FTIR) and thermogravimetry‐mass spectrometry (TG‐MS) and thermal properties by differential scanning calorimetry (DSC) and thermogravimetry (TG). The piezoelectric behavior has been analyzed from remnant polarization measurements. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 722–730, 2009     

Intercalation and Electrochemical Studies of Nitroprusside Anion into Zn-Al Layered Double Hydroxide

The aim of the present work was to investigate the synthesis,characterization and electrochemical properties of the nitroprusside anions (NP)into zinc and aluminium layered double hydroxides (LDHs). The materials were prepared by thecoprecipitation method under constant pH, followed by a hydrothermal treatment. Theprepared materials were characterised by a set of analysis methods, such as powderX-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry(TG), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The resultsshowed that the electrochemical response of NP ions into LDH structure is similar to thatfound for complex ions free in solution. In addition, our results reveal the dependence ofthe electrochemical response on the nature of the supporting electrolyte, for either cationic oranionic species.     

Synthesis,characterization, and thermal properties of ladderlike polyepoxysiloxanes

Starting from trichlorosilanes and using 1,4‐phenylenediamine as a template, we have synthesized some ladderlike poly(glycidyl‐co‐alkyl/aryl)siloxanes (polyepoxysiloxanes or polyepoxies for short). The structures of copolymers were confirmed through IR, ¹H NMR, elemental analyses, and gel permeation chromatography. Curing behaviors of these polyepoxies in the absence and presence of a curing agent have been studied with DSC. It was shown that these epoxies could be cured without any curing agent. Copolymers having aromatic groups showed higher curing reactivity than those having alkyl groups. The experimental results also demonstrate that the curing reaction occurred solely via epoxy functionality, not via the condensation reaction of the hydroxy groups located at the end of polymer main chains. The thermal stability of the cured polymers was examined by thermogravimetric analysis. The results confirm that polyepoxies with aromatic groups had better thermal stability than those with alkyl groups. It was also found that polyepoxies cured with a diamine have a higher thermal stability than those cured in the absence of a curing agent. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2215–2222, 2001     

Synthesis,characterization, and thermal properties of silicon(IV) compounds containing amidinate ligands as CVD precursors

The title compounds of the type R-C(=NⁱPr) (-N′ ⁱPrSiMe₃) (with R = Me or ⁿBu) as potential chemical vapor deposition (CVD) precursors have been synthesized and characterized by ¹H, ¹³C, and ²⁹Si NMR spectroscopy as well as by EI-MS and elemental analysis where necessary. Thermal properties, including stability, volatility, transport behavior, and vapor pressure, were evaluated by thermogravimetric analysis to confirm that they are suitable for the CVD procedure. Deposition was accomplished in a hot wall CVD reactor system, which qualitatively verified the ability of these compounds as CVD precursors.     

药物-无机复合材料姜黄素嵌入镁铝水滑石的合成、表征及缓释性能的研究

采用共沉淀和离子交换方法将药物姜黄素(Cur)嵌入到Mg-Al-LDHs层间,制备了一种新型的药物-无机复合材料,借助XRD,FTIR和TG-DTA等手段对样品进行了表征。结果表明,Cur阴离子以平行或者单层、沿其短轴方向垂直嵌入到层间;与主体层板通过氢键与静电作用形成超分子结构;该超分子结构姜黄素-水滑石复合材料与姜黄素相比,其热稳定性、耐酸性及缓释性能均有大幅度提高,缓释实验数据符合Bhaskar方程和一级动力学方程模型。