Showing papers on "Thermogravimetric analysis published in 2016"
TL;DR: In this article, hydroxylated hexagonal boron nitride (h-BN) was prepared by heating h-BN under air, and then covalently incorporated into epoxy resin modified with (3-isocyanatopropyl)triethoxysilane to prepare epoxy resins by sol-gel process.
Abstract: The structure of hexagonal boron nitride (h-BN) is similar to that of graphite before functionalization and exfoliation. For applications in polymer nanocomposites, chemical exfoliation is a more economically attractive route to few-layer h-BN nanosheets. A thermal oxidation process of h-BN powder could achieve large scale exfoliation and hydroxylated functionalization, as described in prior literature. In this report, hydroxylated h-BN (BNO) was prepared by heating h-BN under air, and then covalently incorporated into epoxy resin modified with (3-isocyanatopropyl)triethoxysilane to prepare epoxy resin (EP) nanocomposites by sol–gel process. The structure and morphology of BNO were well characterized. BNO was dispersed in the EP matrix with the form of mainly exfoliated and intercalated structures, and formed strong interfacial interaction with the matrix. Thermogravimetric analysis results revealed that BNO significantly improved thermal stability and thermal oxidative resistance of EP nanocomposites at high temperature. The char yield and the temperature at 50 wt% mass loss were increased and the maximum mass loss rate was remarkably reduced. Moreover, the addition of 3 wt% BNO led to extremely high Tg of EP nanocomposite, 42.7 °C higher than that of pure EP, due to improved crosslinking density and confinement effect of BNO sheets on the mobility of polymer networks. Cone calorimeter test results indicated that fire safety properties of EP nanocomposites were also enhanced by the addition of BNO, such as 53.1% reduction in peak heat release rate and 32.6% decrease in total heat release, and decreased release of smoke and toxic gases. The mechanism for enhanced fire retardancy is that thermally stable condensed barrier consisting of h-BN sheets and silicon dioxide for heat and mass transfer protects the matrix from further combustion.
325 citations
TL;DR: In this paper, magnetic oxidized multiwalled carbon nanotube (OMWCNT)-Fe3O4 and OMWCNT-κ-carrageenan-Fe 3O4 nanocomposites were synthesized and used as adsorbent for the removal of methylene blue (MB) from aqueous solution.
315 citations
TL;DR: In this paper, a comprehensive study was conducted on the properties of chars which derived from hydrothermal carbonization (HTC) of sewage sludge (SS) while varying the operation parameters as reaction temperature 180-300°C, reaction time 30-480min.
296 citations
TL;DR: In this study microcrystalline cellulose was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation and the improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications.
Abstract: In this study microcrystalline cellulose (MCC) was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The treated cellulose slurry was mechanically homogenized to form a transparent dispersion which consisted of individual cellulose nanofibers with uniform widths of 3-4 nm. Bio-nanocomposite films were then prepared from a polyvinyl alcohol (PVA)-chitosan (CS) polymeric blend with different TEMPO-oxidized cellulose nanofiber (TOCN) contents (0, 0.5, 1.0 and 1.5 wt %) via the solution casting method. The characterizations of pure PVA/CS and PVA/CS/TOCN films were performed in terms of field emission scanning electron microscopy (FESEM), tensile tests, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results from FESEM analysis justified that low loading levels of TOCNs were dispersed uniformly and homogeneously in the PVA-CS blend matrix. The tensile strength and thermal stability of the films were increased with the increased loading levels of TOCNs to a maximum level. The thermal study indicated a slight improvement of the thermal stability upon the reinforcement of TOCNs. As evidenced by the FTIR and XRD, PVA and CS were considered miscible and compatible owing to hydrogen bonding interaction. These analyses also revealed the good dispersion of TOCNs within the PVA/CS polymer matrix. The improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications.
222 citations
TL;DR: In this paper, mesoporous activated carbon (AC) was prepared from sewage sludge of industrial laundry by slow pyrolysis followed of physical activation with CO2 and applied to remove reactive dye Remazol Brillant Blue R (RBBR) from aqueous solutions.
214 citations
TL;DR: In this article, a chitosan functionalized graphene oxide (GO) was proposed as an efficient adsorbent to improve arsenic adsorption from aqueous solutions, which is a good host of welcoming the incoming guest, arsenic oxyanion.
Abstract: Nowadays, there is a wide variety of arsenic decontamination processes being adsorption processes the most efficient. In this concern, chitosan functionalized graphene oxide (GO), have been proposed as an efficient adsorbent to improve arsenic adsorption from aqueous solutions. The chitosan functionalized GO adsorbent acts as a good host of welcoming the incoming guest, arsenic oxyanion and several interesting interactions such as cation–π interaction, (RNH 3 + ---aromatic π moiety), electrostatic interaction (H 2 AsO 4 − , HAsO 4 2− ---- + NH 3 R), inter and intermolecular hydrogen bonding as well as anion–π interaction (R-COO − ---aromatic π moiety), (R–O − ---aromatic π moiety), could be conceptualized in this process, the abundant oxygen-containing functional groups on the adsorbent surfaces play an important role on As(V)/As(III) adsorption. The prepared chitosan-GO adsorbent was characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric analysis (TGA) analysis, powder-X-ray diffraction (powder-XRD), transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopes (SEM) and energy dispersive X-ray analysis (EDX) studies. The capability of ICP-MS for As(III)/As(V) adsorption was extensively studied under different optimal parameters in aqueous solutions, the applicability of this method is demonstrated economical and practical applications for efficient adsorption of arsenic from aqueous solutions.
213 citations
TL;DR: In this article, a novel flame retardant additive with phosphazene and phosphaphenanthrene groups hexa-[4-(p -hydroxyanilino-phosphaphenantrene-methyl)-phenoxyl]-cyclotriphosphazene defined as CTP-DOPO was successfully synthesized from hexachlorocyclotri phosphazenes, p -hydroxybenzaldehyde, 4-aminophenol and 9,10-dihydro-9-oxa-10-phophosphamide 10-
210 citations
TL;DR: In this article, the application of ammonium polyphosphate (APP) in different types of commodity thermoplastic composites (polyethylene, polypropylene (PP), polystyrene (PS), poly(methyl methacrylate) (PMMA) and poly(ethylene terephthalate) (PET)) have been discussed in terms of mechanical properties, morphologies and thermal properties.
Abstract: The application of ammonium polyphosphate (APP) in different types of commodity thermoplastic composites (polyethylene, polypropylene (PP), polystyrene (PS), poly(methyl methacrylate) (PMMA) and poly(ethylene terephthalate) (PET)) have been discussed in terms of mechanical properties, morphologies and thermal properties. In addition, engineering thermoplastics such as acrylonitrile-butadiene-styrene (ABS), polyamides and poly(vinyl alcohol) (PVOH) and their composites added with APP and other additives were analyzed as well. It was suggested that improvement of mechanical properties and morphologies of the thermoplastic composites could be made possible with appropriate amount of APP and other additives such as montmorillonite (MMT), pentaerythritol (PER) and different types of layered double hydroxide (LDH). Furthermore, thermal properties such as limiting oxygen index (LOI) values together with cone calorimetry and thermogravimetric analysis (TGA) performance could be enhanced through optimum combination of APP, PER and melamine which functions as intumescent flame retardant (IFR).
202 citations
TL;DR: In this paper, the effect of contact time, initial dye concentration, pH and temperature on the adsorption process was investigated, and the equilibrium time was determined to be 300min.
197 citations
TL;DR: The nanocomposite exhibited good stability on CO2 adsorption/desorption performance, indicating that the as-prepared emerging nanocomPOSite show an interesting application potential in the field of CO2 capture.
Abstract: Pristine halloysite nanotubes (HNTs) were pretreated to produce mesoporous silica nanotubes (MSiNTs), which was further impregnated with polyethenimine (PEI) to prepare an emerging nanocomposite MSiNTs/PEI (MP) for CO2 capture. Thermogravimetric analysis (TGA) was employed to analyze the influences of PEI loading amount and adsorption temperature on CO2 adsorption capacity of the nanocomposite. The Brunauer–Emmett–Teller (BET) surface area (SBET) of MSiNTs was six times higher than that of HNTs, and the corresponding pore volume was more than two times higher than that of HNTs. The well dispersion of PEI within the nanotubes of MSiNTs benefits more CO2 gas adsorption, and the adsorption capacity of the nanocomposite could reach 2.75 mmol/g at 85 °C for 2 h. The CO2 adsorption on the nanocomposite was demonstrated to occur via a two-stage process: initially, a sharp linear weight increase at the beginning, and then a relatively slow adsorption step. The adsorption capacity could reach as high as 70% within...
190 citations
TL;DR: In this paper, a fabricated sensor based on 3.8 wt% reduced graphene oxide/hexagonal WO3 (rGO/h-WO3) nanosheets composites was synthesized through hydrothermal method and post-calcination treatment.
Abstract: Reduced graphene oxide/hexagonal WO3 (rGO/h-WO3) nanosheets composites were synthesized through hydrothermal method and post-calcination treatment. The products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N2 adsorption-desorption, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The results showed that two-dimensional (2D) h-WO3 nanosheets with porous structure were attached on rGO to construct 3D rGO/h-WO3 hybrid nanocomposites. This 3D hybrid nanostructure provided many channels for gas diffusion. The fabricated sensor based on 3.8 wt% rGO/h-WO3 composites showed good gas sensing response to H2S. The sensitivity of the sensor was about 168.58 toward 40 ppm H2S, which was 3.7 times higher than that of pure WO3, and the response time was 7 s when exposed to 10 ppm H2S. Moreover, the sensor showed low detection limit (10 ppb), wide linear range and high selectivity to H2S. The improved gas sensing properties of 3.8 wt% rGO/h-WO3 composites may be attributed to the formation of hetero-junctions, good accepting/transporting electrons properties of rGO and effective gas transport channels in 3D hybrid nanostructure.
15 Dec 2016
TL;DR: Graphene oxide was encapsulated into environmentally benign sodium alginate to prepare a GO-SA composite hydrogel and an aerogel, which were then used as adsorbents to remove ciprofloxacin from aqueous solutions to show high tolerance to changes in pH and ionic strength.
Abstract: Graphene oxide (GO) was encapsulated into environmentally benign sodium alginate (SA) to prepare a GO-SA composite hydrogel and an aerogel, which were then used as adsorbents to remove ciprofloxacin from aqueous solutions. The characteristics of these materials were investigated using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The characterizations demonstrated that the incorporation of GO improved the pore uniformity of the gels and decreased the pore sizes. Kinetic studies showed that the adsorption capacity of SA composite gels increased approximately seven to nine times after the incorporation of GO, matching with pseudo-second-order models. Non-linear fitting parameters of adsorption isotherm studies indicated that a Langmuir model could precisely represent the adsorption behavior. GO-SA aerogels exhibited high tolerance to changes in pH and ionic strength; changes in these parameters minimally influenced the adsorption capacity of the GO-SA aerogels for ciprofloxacin. This work is especially relevant for environmental applications. These graphene-based composites are environmentally benign adsorbents and can remove organic contaminants from aqueous solutions.
TL;DR: In this article, the elaboration and characterization of hydrophobic melamine-based sponges are presented. And the relationship between hydrophobicity and physicochemical evolution on heat treatment (carbonization process, diffusion of additives, porosity evolution) was studied.
TL;DR: With increase of oxidant content in the two methods, the carboxyl groups on the surfaces of TEMPO-oxidized CCNs and AO-CCNs were both improved and a remarkable decline of the DPv of cellulose sample also appeared in theTwo oxidative treatments.
TL;DR: In this article, pyrolysis characteristics of three main components (hemicellulose, cellulose and lignin) of biomass were investigated using a thermogravimetric analyzer and a fixed-bed reactor, respectively.
TL;DR: In this paper, a double cleaning process was used to convert waste rubber tires into activated carbon by pyrolysis, activation and chemical treatment with 4M HNO 3 for 3h at 90°C for the enhancement of surface functionalities.
TL;DR: An in situ method for CNF surface modification and hydrophobic aerogel preparation is presented that shows high absorption capacities for various oils, depending on liquid density, up to 47× their original weight but with low water uptake.
Abstract: Aerogels based on cellulose nanofibrils (CNFs) have been of great interest as absorbents due to their high absorption capacity, low density, biodegradability, and large surface area. Hydrophobic aerogels have been designed to give excellent oil absorption tendency from water. Herein, we present an in situ method for CNF surface modification and hydrophobic aerogel preparation. Neither solvent exchange nor fluorine chemical is used in aerogel preparations. The as-prepared hydrophobic aerogels exhibit low density (23.2 mg/cm–3), high porosity (98.5%), good flexibility, and solvent-induced shape recovery property. Successful surface modification was confirmed through field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and water contact angle measurements. The hydrophobic aerogels show high absorption capacities for various oils, depending on liquid density, up to 47× their original weight but with low water uptake (<0.5 g/g a...
TL;DR: In this article, a novel environmental friendly adsorbent H6P2W18O62/MOF-5 was synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, FTIR, thermogravimetric analyses (TGA) and N2 adsorption-desorption isotherms.
TL;DR: In this article, pyrolysis test for soybean straw was performed in a non-isothermal thermogravimetric analysis (TGA) in order to determine the thermal degradation behavior.
TL;DR: There was a positive synergistic interaction between biomass and plastics according to the difference of weight loss, which could decrease the formation of solid residue at the end of the experiment, and it was suggested that the catalytic co-pyrolysis is a promising technique that can significantly reduce the energy input.
TL;DR: In this paper, the performance of B-Mg(OH)2 composite to remove dyes was examined at different initial concentrations, pH, temperature and ionic strengths, and the results showed that the process was physiosorptive, endothermic and spontaneous.
TL;DR: In this paper, a bentonite-based form-stable composite phase change materials (Bb-FSPCMs) were produced by impregnation of capric acid (CA), polyethylene glycol (PEG600), dodecanol (DD) and heptadecane (HD) into bentonite clay.
TL;DR: In this paper, Fourier transform infrared (FTIR) spectroscopy was utilized in order to study the chemical structure of the developed coatings, and the coating surface wettability was studied by contact angle measurements and the dispersion of ZnO nanoparticles was examined via field emission scanning electron microscope (FESEM).
TL;DR: Results of this study showed that thermal decomposition temperature depends on the polymer ratio (R) and thermal resistance of samples was improved by increasing chitosan dosage, and polyelectrolyte complexation led to obtain more flexible and resistant to mechanical deformation materials.
Abstract: Biomaterials based on polyelectrolyte complexation are an innovative concept of coatings and packaging production to be applied in a wide range of food products. The aim of this study was to obtain and characterize a sodium alginate–chitosan complex material with variable degree of polyion interactions by complexation of oppositely charged polysaccharides. In order to characterize polyelectrolyte complexes, theromogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), matrix-assisted laser desorption/ionization technique with time of flight analyzer (MALDI-TOF), and scanning electron microscopy (SEM) were performed. TGA analysis showed that thermal decomposition temperature depends on the polymer ratio (R) and thermal resistance of samples was improved by increasing chitosan dosage. Accordingly to DMTA results, polyelectrolyte complexation led to obtain more flexible and resistant to mechanical deformation materials. Comparative analysis of the FTIR spectra of single polyelectrolytes, chitosan and alginate, and their mixtures indicated the formation of the polyelectrolyte complex without addition of reinforcing substances. MALDI-TOF analysis confirms the creation of polyelectrolyte aggregates (~197 Da) in samples with R ≥ 0.8; and their chemical stability and safety were proven by NMR analysis. The higher R the greater the number of polyanion–polycation aggregates seen in SEM as film morphology roughness.
TL;DR: In this paper, the authors reported the synthesis and evaluation of novel ironoxide/CNTs nanocomposites for oil-water separation, which were doped with different loadings of iron oxide nanoparticles using a wet impregnation technique.
TL;DR: The Pd/PAC-modified glassy carbon electrodes (GCEs) were exploited as electrochemical sensors for the detection of toxic heavy metal ions, which showed superior performances for both individual as well as simultaneous detections.
Abstract: A facile method has been developed for fabricating selective and sensitive electrochemical sensors for the detection of toxic metal ions, which invokes incorporation of palladium nanoparticles (Pd NPs) on porous activated carbons (PACs). The PACs, which were derived from waste biomass feedstock (fruit peels), possess desirable textural properties and porosities favorable for dispersion of Pd NPs (ca. 3–4 nm) on the graphitic PAC substrate. The Pd/PAC composite materials so fabricated were characterized by a variety of different techniques, such as X-ray diffraction, field-emission transmission electron microscopy, gas physisorption/chemisorption, thermogravimetric analysis, and Raman, Fourier-transform infrared, and X-ray photon spectroscopies. The Pd/PAC-modified glassy carbon electrodes (GCEs) were exploited as electrochemical sensors for the detection of toxic heavy metal ions, viz., Cd2+, Pb2+, Cu2+, and Hg2+, which showed superior performances for both individual as well as simultaneous detections. F...
TL;DR: In this article, the effect of hybridization and coupling agent on the morphological, structural, thermal and mechanical properties of polypropylene hybrid composites was investigated, showing that coupling agent increased filler/matrix interfacial adhesion.
TL;DR: In this paper, the authors investigated the synergistic effects during co-pyrolysis of waste newspaper and high-density polyethylene (HDPE) in order to enhance the oil yield and its fuel properties.
TL;DR: In this article, the use of biobased chitosan-polybenzoxazine (CTS-PBZ) as a precursor for high CO2 adsorbing carbon aerogels (CAs) was reported.
Abstract: The present study reports for the first time the use of biobased chitosan-polybenzoxazine (CTS-PBZ) as a precursor for high CO2 adsorbing carbon aerogels (CAs). Montmorillonite (MMT) is used to reinforce the CTS-PBZ aerogel. MMT-CTS-PBZ nanocomposite aerogels are synthesized using the freeze-drying technique and then cross-linked via ring-opening polymerization of benzoxazine followed by carbonization at 800 °C. Polybenzoxazine improves the structural stability for removing CO2 from the environment even at a high pressure. The properties of polymeric and nanocomposite aerogels have been evaluated using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The microstructure of the CAs is characterized by N2 adsorption–desorption measurements. The CAs exhibit mesoporous materials with pore sizes in the range of 2–7 nm and high BET surface area. The total pore volume of CAs is as large as 0.296 cm3 g–1, and the maximum BET surface area is 710 m2 g–1. Breakthrough curves of CO2 ads...
TL;DR: In this article, a halogen-free flame retardant (DTB) containing phosphorus, nitrogen and boron was successfully synthesized and the chemical structure of DTB was characterized by Fourier transform infrared spectroscopy (FTIR), 1 H and 31 P nuclear magnetic resonance (NMR).