Flame Retardant and Smoke Suppressant of Fe‐Organophilic Montmorillonite in Polyvinyl Chloride Nanocomposites

Two kinds of polyvinyl chloride (PVC)/organophilic montmorillonite (OMT) nanocomposites are prepared by a melt intercalation method. This study has been designed to determine if the presence of iron and zinc ions in the structure of montmorillonite (MMT) lattice can affect thermal, flame retardant and smoke suppressant properties. The information about the morphological structure of PVC/OMT nanocomposites was obtained using X-ray diffraction and transmission electron microscopy. The thermal and flame retardant properties of the nanocomposites were characterized by thermogravimetric analysis, limiting oxygen index and smoke density. The nanocomposites based on Fe-OMT exhibit better thermal, flame retardant properties and lower degradation degree than those of pure PVC. The degradation mechanism was studied by pyrolysis, gas chromatography and mass spectrometry (Py-GC-MS).     

Thermal degradation of organo-soluble polyimides

The thermal degradation behavior of two organo-soluble polyimides was investigated by high resolution pyrolysis-gas chromatography/mass spectrometry. The pyrolyzates of the polymers at various temperatures were identified and characterized quantitatively. The relationship between the polymer structure and pyrolyzate distribution was discussed. The kinetic parameters of the thermal degradation were calculated based on thermogravimetric measurements. Finally, the thermal degradation mechanism for the polymers was suggested.     

SYNTHESIS, CHARACTERIZATION AND THERMAL DEGRADATION KINETICS OF POLY(IMINO ISOPHTHALOYL IMINO (2,4,8,10-TETRAOKSOASPIRO [5,5] UNDEKAN-3,9-DIPROPYLENE))

A new polymer,poly(imino isophthaloyl imino(2,4,8,10-tetraoksoaspiro[5,5]undekan-3,9-dipropylene)) [poly(IPIT)]was synthesized by an interfacial polycondensation reaction.The characterization of poly(IPIT)was conducted by using FT-IR,~(13)C-NMR,TG and DTA techniques.The kinetics of the thermal degradation of poly(IPIT)was investigated by thermogravimetric analysis at different heating rates.TG curves showed that the thermal decomposition of poly(IPIT) occurred in three stages.The apparent activation ener...     

Chemical synthesis, spectral characterization and stability of some electrically conducting polymers

<正>The synthesis,characterization,thermal degradation and stability of polyaniline(PANI),poly(m-nitroaniline), poly(m-chloroaniline) and poly(o-methylaniline) were reported.Different properties were measured and compared with PANI to find out the effect of electron donating groups(-CH_3) and electron withdrawing groups(-Cl,- NO_2).It was found that the presence of any type of substitution in the benzene ring of aniline increased the solubility but reduced the yield,thermal stability and electrical conductivity.Two probe methods were used to measure the electrical conductivity of these polymers.The structural properties of these polymers were characterized by using FTIR and UV-Vis spectroscopic methods.Thermal degradation and stability of these polymers were explained by using thermogravimetric analysis(TGA) and conductivity measurements.     

Ammonium sulfamate flame retarded polyamide 6: Morphology and thermal degradation

<正>The effect of ammonium sulfamate(AS) content on the flame retardancy of polyamide 6(PA6) was studied.It is found that the limiting oxygen index(LOI) of PA6 increases with the increase of AS content and the flame retardancy of PA6 is significantly improved.The morphology of the residues after combustion was examined by means of scanning electron microscopy(SEM).SEM results show that AS facilitates the formation of the intumescent char layer with honeycomb-like structure,which inhibits the transfer of heat and mass,and thus improves the flame retardancy of PA6.The thermal degradation of AS flame retarded PA6 was studied by thermogravimetric analysis(TGA).The Kissinger method was applied to estimate the activation energy(E_a) of the degradation.The activation energy of the thermal degradation of PA6 decreases by adding AS,indicating that AS can promote the degradation of PA6.     

Photoactivity of titanium dioxide/carbon felt composites prepared with the assistance of supercritical carbon dioxide: Effects of calcination temperature and supercritical conditions

TiO2-coated carbon felt(TCF)composite catalysts have been prepared via a supercritical treatment of titanium tetraisopropoxide(TTIP)as the precursor.The physical properties of the catalysts were characterized by means of thermogravimetric and differential thermal analysis(TG–DTA),X-ray diffraction(XRD),fluorescence spectroscopy,scanning electron microscopy (SEM),and BET surface areas techniques.The photocatalytic activities of the materials were evaluated using the degradation of Congo red(CR)as a probe rea...     

Synthesis and characterization of a methacrylate polymer with side chain ketone and its derivatives

A new type of methacrylate monomer,2-(4-benzoylphenoxy)-2-oxoethyl methylacrylate(BOEMA) was synthesized.The radical homopolymerization of BOEMA was performed at 65℃in a 1,4-dioxane solution with benzoyl peroxide as an initiator.The oxime and thiosemicarbazone derivatives of poly[2-(4-benzoylphenoxy)-2-oxoethyl methylacrylate]poly(BOEMA) were prepared with hydroxylamine hydrochloride,and thiosemicarbazone hydrochloride, respectively.The monomer and its homopolymer were characterized with Fourier transform infrared and NMR techniques. The thermal stabilities of poly(BOEMA) and its derivatives were investigated with thermogravimetric analysis and differential scanning calorimetry.The ultraviolet stability of the polymers was compared.The antibacterial and antifungal effects of the monomer and the polymer and its derivatives were also investigated on various bacteria and fungi.The activation energies of the thermal degradation of the polymers were calculated with the Ozawa and Kissinger methods.     

Thermal Kinetics and Decomposition Mechanism of Methylphenylphosphinic Acid and Diphenylphosphinic Acid

Thermal degradation and degradation kinetics of methylphenylphosphinic acid（MPPA） and diphenyl- phosphinic acid（DPPA） were investigated via thermogravimetric analysis（TGA） technique under non-isothermal conditions. The activation energies of the decomposition process for the two compounds were calculated through the Friedman and Kissinger-Akahira-Sunose（KAS） methods. The thermal decomposition mechanism was investigated by the Criado method based on a set of TGA data obtained at different heating rates. It was shown that the activation energies calculated from the decomposition reaction by different methods were consistent with each other. The results show that the probable model for the degradation of MPPA and DPPA agreed with the two-dimensional（D2） and three-dimensional（D4） diffusion models, respectively. Moreover, the thermodynamic functions（△H, △S, △G） of the two decomnosition reactions were also calculated.     

Study on the Novel Dicyanate Ester Resin Containing Naphthalene Unit

The novel dicyanate ester resin containing naphthalene unit (DNCY) was synthesized,and characterized by FT-IR,^1H-NMR,^13C-NMR and elemental analysis (EA),The thermal properties of DNCY resin was studied by thermal degradation analysis at a heating rate of 10℃/min^-1 in N2 and air,The DNCY rdsin exhibited better thermal and thrmal-oxidative stability than bisphenol A dicyanate (BACY)resin.     

碱促进的钴酸镁催化剂上的氧化亚氮分解

The direct decomposition of N2O was investigated over a series of magnesium cobaltite catalysts,MgxCo1-xCo2O4(0.0 ≤ x ≤ 1.0) ,which were prepared by the thermal decomposition of stoichiometric amounts of magnesium hydroxide and cobalt acetate. The thermal genesis of the different catalysts from their precursors was explored using thermogravimetric analysis,differential thermal analysis,and X-ray diffraction. Texture analysis was carried out using N2 adsorption at -196 °C. We found that all the catalysts tha...     

阳离子染料可染聚对苯二甲酸丙二酯共聚酯的合成及结晶性能的研究

通过直接酯化-缩聚工艺,在聚对苯二甲酸丙二酯(PTT)聚合的酯化过程中加入第三组分间苯二甲酸丙二酯-5-磺酸钠(SIPP),在缩聚过程中加入第四组分聚1,6-己二酸-1,4-丁二醇酯(PBA)或聚乙二醇(PEG)合成了一系列不同的阳离子染料可染PTT,采用氢核磁共振波谱(1H-NMR)、差示扫描量热仪(DSC)和热重分...     

Morphology and thermal properties of polyhedral oligomeric silsesquioxane/polybutadiene nanocomposites prepared by anionic polymerization

The morphology and thermal properties of Allylisobutyl Polyhedral Oligomeric Silsesquioxane (POSS)/Polybutadiene (PB) nanocomposites prepared through anionic polymerization technique were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results of XRD, SEM and TEM showed that the aggregation of POSS in PB matrix occurred obviously, forming crystalline domains and the size of POSS particles increased with increasing POSS content. The DSC and TGA results indicated that the glass transition temperature (T _g) of the nanocomposites was significantly increased and the maximum degradation temperature (T _dmax) of nanocomposites was slightly increased compared with pure PB, implying an increase in thermal stability.     

Organic/inorganic hybrid materials from an epoxy resin cured by an amine silsesquioxane

The thermal behaviour of an epoxy resin cured with an amine-POSS was studied using differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The kinetic of polymerization reaction and the thermal degradation have been analyzed based on an iso-conversional model. The obtained results showed that the activation energies of both processes depend on the degree of conversion.     

Crystallization behavior and thermal stability of poly(trimethylene terephthalate)/clay nanocomposites

Poly(trimethylene terephthalate) (PTT)/montmorillonite (MMT) nanocomposites were prepared by the solution intercalation method. Two different kinds of clay were organomodified with an intercalation agent of cetyltrimetylammonium chloride (CMC). X‐ray diffraction (XRD) indicated that the layers of MMT were intercalated by CMC, and interlayer spacing was a function of the cationic exchange capacity of clay. The XRD studies demonstrated that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay. From the results of differential scanning calorimetric analysis, it was found that clay behaves as a nucleating agent and enhances the crystallization rate of PTT. The maximum enhancement of the crystallization rate for the nanocomposites was observed in nanocomposites containing about 1 wt % organoclay with a range of 1–15 wt %. From thermogravimetric analysis, we found that the thermal stability of the nanocomposites was enhanced by the addition of 1–10 wt % organoclay. According to transmission electron microscopy, the organoclay particle was highly dispersed in the PTT matrix without a large agglomeration of particles for a low organoclay content (5 wt %). However, an agglomerated structure did form in the PTT matrix at a 15 wt % organoclay content. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2902–2910, 2003     

Thermal degradation study of gadolinium and lutetium methanesulfonates

The synthesis, characterization and thermal degradation study of gadolinium and lutetium methanesulfonates is reported. The prepared salts were characterized by elemental analysis and infrared spectroscopy. The thermal degradation study was performed by using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). By using thermogravimetric data, a kinetic study of the dehydration of Gd and Lu methanesulfonates is performed employing the Coats-Redfern and Zsakó methods. It is verified that under heating, the gadolinium and lutetium methanesulfonates suffer three main processes: dehydration, thermal degradation and oxide formation. The thermal degradation products were characterized by infrared spectroscopy and X-diffractometry. Furthermore, depending on the atmosphere nature, i.e. inert or oxidant, the thermal degradation process could be endothermic (N₂) or exothermic (air).     

Characterization of sugarcane and coconut fibers by thermal analysis and FTIR

Pyrolysis of sugarcane bagasse and coconut fiber was studied by thermal analysis in order to characterize their thermal behavior and to identify their constituents by the aid of their thermogravimetric curves and to determine their heat capacity by means of DSC. The Fourier Transform Infrared Spectrum (FTIR) was used to determine the main constituents present in both residues. The thermal degradation of sugarcane bagasse and coconut fiber presents two mass loss steps attributed to the release of humidity and to the decomposition of organic material (hemicellulose, cellulose and lignin). It was expected that the results of DSC analysis were almost the same for both types of biomasses.     

Investigation of the multiple melting behaviour of a PTT by DSC and polarized light optical microscopy

The multiple melting behaviour of isothermally crystallized bulk poly(trimethylene terephthalate) (PTT) observed using DSC has been correlated to the total depolarized light intensity (DLI) of thin films using hot-stage polarized light optical microscopy. The observation of partial melting, recrystallization and final melting in the DSC is correlated to the observation of the partial decrease, sudden increase and final decrease in DLI under the same heating conditions. Integration of real-time visible spectra of the transmitted light was used to separate the effects of retardation from pure birefringence of the colorful spherulitic thin-film PTT samples. The correlation of the results from these two methods has demonstrated clearly that the observed DSC multiple melting behaviour of this particular polymer is the illustrated effect of a process of continuous partial melting/recrystallization/final melting in the material during thermal analysis. The observed thermal behaviour of these metastable spherulitic materials is a complex function of their thermal history including crystallization temperature and anneal conditions, including scanning rate during thermal analysis.     

Thermal Decomposition of Triazine Herbicides II. 6-Chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (atrazine) and its metabolites

Thermal degradation of atrazine and its metabolites has been investigated using a thermogravimetric technique(TG) with the application of three types of crucibles: opened, Knudsen type and labyrinthtype, and non-isothermal DSC method, using hermetically closed and opened alumina sample pans. The great influence of decomposition conditions (the crucible type) on thermal degradation was observed. TG analysis showed that the degradation process of atrazine took place in three stages. The increase of amino groups in triazine ring increases the amount of non-volatile thermal degradation products by association. The presence of chlorine substituent facilitates the forming of products with low volatility. Hydroxyatrazine decomposes only in one stage process. The dealkylation process observed in hermetical sample pans (DSC) was two-stage and in open sample pans one-stage process. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation and physical properties of poly(trimethylene terephthalate)/metallocene isotactic polypropylene conjugated fibers

Poly(trimethylene terephthalate) (PTT) and metallocene isotactic polypropylene (MIPP) polymers were extruded (in the proportions of 75/25, 50/50, 25/75) from two melt twin-screw extruders to prepare three PTT/MIPP conjugated fibers. This study investigated the preparation and physical properties of PTT/MIPP conjugated fibers using gel permeation chromatograph (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), potentiometer, a rheometer, the density gradient, wide-angle X-ray diffraction (WAXD), extension stress-strain measurement and scanning electron microscope (SEM). Melting behavior of PTT/MIPP polyblended polymers exhibited negative-deviation blends (NDB) and the 50/50 blend of PTT/MIPP showed a minimum value of the melt viscosity. Experimental results of the DSC indicated PTT and MIPP molecules formed immiscible system. The tenacity of PTT/MIPP conjugated fibers decreased initially and then increased as the MIPP content increased. Crystallinities and densities of PTT/MIPP conjugated fibers were the linear relation with the blend ratio. PTT and MIPP polymers were proved to be an incompatible system. On the morphological observation, it was revealed that the blends were in a dispersed phase structure. The pore/fiber morphology of a larger size from 0.5 to 3 μm in diameter was observed after 1,1,1,3,3,3-hexafluoro-2-propanol (PTT was removed)/paraffin oil (MIPP was removed) treatment on the cross-section of PTT/MIPP conjugated fiber. In this paper, PTT micro fibers were produced successfully.     

Preparation and investigation on tetradecanol and myristic acid/cellulose form-stable phase change material

In this paper, a novel form-stable phase change material (FS PCM) was prepared by incorporating the eutectic mixture of tetradecanol (TD) and myristic acid (MA) into the hydroxylpropyl methyl cellulose (HPMC). HPMC is used as support material, and the eutectic mixture is used as phase change material. The Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and scanning electron microscopy (SEM) were used to study the chemical structure, crystallization behavior and morphology of the FS PCM, respectively. FT-IR, XRD and SEM showed that the TD–MA was distributed uniformly in HPMC by physical interaction. Specific surface area (BET) and pore size analysis determined the pore characteristics of the composite, and the results showed the porosity of HPMC. The thermal properties, thermal stability and thermal reliability were detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermal cycling test and leakage test. The TG, DSC and leakage analysis results revealed that the absorption of eutectic mixture into HPMC is nearly 50% and without seepage from the composite. The peak temperatures of melting and solidifying were 34.61 and 31.09 °C, and latent heat was 102.11/84.58 J g^?1 by DSC. TG and cycling experiment detected that the FS PCM showed good thermal stability and reliability performance.