Differential Scanning Calorimetry Thermogravimetric Analysis Research Articles

Structure and Photocatalytic Activity of Nitrogen-doped HTiNbO5 Nanosheet Aggregation

Nitrogen-doped HTiNbO5 nanosheet (N-HTiNbO5-NS) aggregation was successfully obtained through a series of process, including preparation of nitrogen-doped precursor (N-KTiNbO5), proton-exchange of N-KTiNbO5 and exfoliation of N-HTiNbO5. The structures of the as-prepared samples are characterized by means of powder X-ray diffraction (XRD), Scan electron microscopy (SEM), Transmission electron microscopy (TEM), N2 adsorption-desorption isotherms UV-visible diffuse reflectance spectroscopy (UV-Vis-DRS), Laser Raman spectroscopy (LRS), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis-differential scanning calorimetry (TG-DSC). The catalytic activities of the as-prepared samples are evaluated by the photocatalytic degradation of methylene blue (MB) aqueous solution under visible light irradiation. The results reveal that N-HTiNbO5-NS due to the large specific surface area and brilliant visible light response exhibits a relatively excellent photocatalytic activity in the decomposition of MB under visible light irradiation.

Structural and Stability Studies of a Series of para-Phenylenediboronic and para-Hydroxyphenylboronic Acid Cocrystals with Selected Aromatic N-Oxides

Nine new cocrystals of para-phenylenediboronic or para-hydroxyphenylboronic acids with a series of aromatic N-oxides are reported. All of the complexes form centrosymmetric crystal structures. They are stabilized by an extended net of hydrogen bonds further supported by effective π-stacking interactions. In the studied structures four main synthons were distinguished. Only in the 3,10-phenanthroline-3-N-oxide and 3,10-N,N-dioxide cocrystals from the series, an acid–acid dimeric motif characteristic for arylboronic acid crystals was observed. The majority of the obtained cocrystals exhibit layered architectures, where the N-oxide molecules are separated by boronic acid slabs. Furthermore, most of the cocrystals form hydrates, where water molecules play the role of a “molecular glue”. Water contribution to the lattice stability is significant, and energy gain per water molecule ranges from 66.8 to 117.6 kJ·mol–1. The cocrystal cohesive energies seem to be more favorable when compared to the corresponding values for crystals of their components. However, the presence of various asymmetric unit contents and numerous hydrated crystal structures indicates that the crystallization process and the final products are highly dependent on kinetic and entropy factors. Finally, the calculated energetic features are compared with the experimental thermogravimetric analysis–differential scanning calorimetry results obtained for selected cocrystals.

Pyrolysis of commingled waste textile fibers in a batch reactor: Analysis of the pyrolysis gases and solid product

ABSTRACTThe main object of this study was the investigation of the thermal recycling of commingled waste textile fibers, with the aim of the production of useful end products. Differential scanning calorimetry/Thermo gravimetric analysis (DSC/TGA) was applied to determine the thermal degradation characteristics of the commingled waste textile fibers and there are two peaks located at the temperature ranges of 299–360°C and 399–500°C. Commingled waste fiber was pyrolyzed in a nitrogen atmosphere in relation to three different temperatures (500, 600, and 700°C), heating rates (25 and 50°C min−1), and retention times (15 and 30 min). The effect of the experimental conditions such as pyrolysis temperature, heating rates, and retention time on the formation of char and gas--liquid products was investigated and the product yields were determined from the rate of the weight loss. The highest conversion rate 82.9 wt.% liquid--gas product and 17.1 wt.% char product was achieved at 700°C. Pyrolysis gases were taken for every 7, 15, and 25 min and were analyzed for major components such as CO, CO2, CH4, and H2 by gas chromatography. The pyrolysis char called as carbon black derived from the pyrolysis of commingled waste textile fibers was analyzed for a range of properties, including the elemental analysis, moisture content, ash content, calorific value, and trace metal analysis.

Crystallization of interphase droplets in emulsion explosive matrices

ABSTRACTThe instability of emulsion explosive matrices is mainly due to the crystallization of interphases as oversaturated aqueous solutions of nitrate salts. The principal features of crystallization for this type of emulsion have been previously studied; however, there is no consensus regarding the mechanism of crystallization for an emulsion explosive matrix. This study is devoted to the investigation of the crystallization behavior of interphase droplets. By monitoring the mass change of emulsions during their aging process, it was found that the mass of the emulsions remains almost constant and that water still completely existed in the emulsion system after crystallization of the interphase droplets. The ammonium nitrate (NH4NO3) crystals in the emulsion explosive matrices were then separated successfully using a simple method. The thermal behavior of pure NH4NO3 and crystals in the emulsion explosive matrices was studied by differential scanning calorimetry-thermogravimetric analysis (DSC-TG) at a heating rate of 10 K/min. The experimental results show that the thermal behavior of the crystals in the emulsions was exactly the same as for pure NH4NO3, meaning that only NH4NO3 crystallized from the emulsion explosive matrices with no water crystals. Thus, it could be concluded that after crystallization of the dispersed drops in the emulsion explosive matrices, pure NH4NO3 crystals and new smaller droplets were produced.

Morphology and properties of super-toughened bio-based poly(lactic acid)/poly(ethylene-co-vinyl acetate) blends by peroxide-induced dynamic vulcanization and interfacial compatibilization

Super-toughened poly(lactic acid) (PLA)/poly(ethylene-co-vinyl acetate) (EVA) blends were prepared via 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (AD) induced dynamic vulcanization and in situ interfacial compatibilization. The effects of AD on the morphology and properties of PLA/EVA blends were studied using a Brabender torque rheometer, gel content test, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) thermogravimetric analysis (TGA) and mechanical properties test. The torque and gel content demonstrated that EVA and PLA was successfully vulcanized in the presence of free radicals obtained by the decomposition of the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (AD). Additionally, the gel content results indicated that, compared with PLA, EVA is more aggressive with free radicals. The SEM revealed that a relatively uniform phase morphology and good interfacial compatibilization were achieved in the dynamically vulcanized PLA/EVA/AD blends. The interfacial reaction and compatibilization between the component polymers resulted in the formation of super-toughened PLA/EVA blended materials.

Magnetically separable maghemite/montmorillonite composite as an efficient heterogeneous Fenton-like catalyst for phenol degradation.

To develop highly efficient and conveniently separable iron containing catalysts is crucial to remove recalcitrant organic pollutants in wastewater through a heterogeneous Fenton-like reaction. A maghemite/montmorillonite composite was synthesized by a coprecipitation and calcination method. The physiochemical properties of catalysts were characterized by XRD, TEM, nitrogen physisorption, thermogravimetric analysis/differential scanning calorimetry (TG/DSC), zeta potential, and magnetite susceptibility measurements. The influence of calcination temperatures and reaction parameters was investigated. The calcined composites retain magnetism because the presence of montmorillonite inhibited the growth of γ-Fe2O3 nanoparticles, as well as their phase transition. The catalytic activities for phenol degradation were significantly enhanced by calcinations, which strengthen the interaction between iron oxides and aluminosilicate framework and result in more negatively charged surface. The composite (73m2/g) calcined at 350°C had the highest catalytic activities, with more than 99% phenol reduction after only 35min reaction at pH 3.6. Simultaneously, this catalyst exhibited high stability, low iron leaching, and magnetically separable ability for consecutive usage, making it promising for the removal of recalcitrant organic pollutants in wastewater.

Thermo-physical characteristics of nickel-coated aluminum powder as a function of particle size and oxidant

Aluminum particles 15–25 μm in size are widely used in fuel propellants and underwater propulsion systems in national defense research. However, these particles are covered with an aluminum oxide film, which has a high melting point, so ignition is difficult. To improve the ignitability of high-energy aluminum powder and to understand the reaction phenomenon as a function of particle size(15–25 μm, 74–105 μm, and 2.38 mm) and oxidizer(air, CO2, and argon), the natural oxide films are chemically removed. The particles are then coated with nickel using an electro-less method. The degree of nickel deposition is confirmed qualitatively and quantitatively through surface analysis using scanning electron microscopy/energy dispersive spectroscopy. To characterize the nickel coatings, elemental analysis is also conducted by using X-ray diffraction. Thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) enable comparisons between the uncoated and coated aluminum, and the reaction process are investigated through fine structural analysis of the particle surfaces and cross sections. There are little difference in reactivity as a function of oxidant type. However, a strong exothermic reaction in the smaller nickel-coated aluminum particles near the melting point of aluminum accelerates the reaction of the smaller particles. Explanation of the reactivity of the nickel-coated aluminum depending on the particle sizes is attempted.

Thermochemical Characterizations of Novel Vermiculite-LiCl Composite Sorbents for Low-Temperature Heat Storage

To store low-temperature heat below 100 °C, novel composite sorbents were developed by impregnating LiCl into expanded vermiculite (EVM) in this study. Five kinds of composite sorbents were prepared using different salt concentrations, and the optimal sorbent for application was selected by comparing both the sorption characteristics and energy storage density. Textural properties of composite sorbents were obtained by extreme-resolution field emission scanning electron microscopy (ER-SEM) and an automatic mercury porosimeter. After excluding two composite sorbents which would possibly exhibit solution leakage in practical thermal energy storage (TES) system, thermochemical characterizations were implemented through simulative sorption experiments at 30 °C and 60% RH. Analyses of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) curves indicate that water uptake of EVM/LiCl composite sorbents is divided into three parts: physical adsorption of EVM, chemical adsorption of LiCl crystal, and liquid–gas absorption of LiCl solution. Energy storage potential was evaluated by theoretical calculation based on TGA/DSC curves. Overall, EVMLiCl20 was selected as the optimal composite sorbent with water uptake of 1.41 g/g, mass energy storage density of 1.21 kWh/kg, and volume energy storage density of 171.61 kWh/m3.

Molecular scale studies that inform trace element sulfide evaporation and atomization behavior during coal combustion

Understanding the chemical mechanisms of trace element (TE) evolution is essential for accurate modeling of coal combustion. A novel graphite furnace atomic absorption spectrometry (GFAAS) method was used to simulate the evaporation and atomization behavior of TE sulfides (arsenic, antimony and selenium) in the two distinct microenvironments that mineral inclusions and exclusions experience during the onset of coal combustion. Additional insights were obtained using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC). Potassium polysulfide was used as an additive to water to facilitate the dissolution of all three TE sulfides. TE sulfides in inclusions were studied by adding the test mixture to a graphite tube in a reducing (anaerobic) micro-environment whereas the TE evolution in excluded sulfide minerals was studied by blocking the graphite tube surface with an inert ZrO2 or WO3 coating. Arsenic sulfide, As2S3, exhibits a lower Arrhenius activation energy of atomization, Ea, than that of the corresponding oxide in both mineral inclusions and exclusions, apparently because of the availability of a specific facile path to atomization. A higher Ea was observed for antimony sulfide, Sb2S3, than that of the corresponding oxide from inclusions and is most likely due to its strong binding affinity to the carbon tube surface. The low GFAAS signal of selenium sulfide suggests the formation of molecular clusters, e.g., Se2, Se8 or similar mixed clusters with sulfur atoms prior to vaporization, an effect not observed for selenium oxide evaporation. For all three TE sulfides, either elemental species or unstable sulfides with low sulfur content appear to be predominant in the gas phase associated with both mineral inclusions and exclusions, with TE sulfide evaporation being the rate limiting step. Comparing the GFAAS activation energy values obtained with and without the coating showed that in a reducing micro-environment (anaerobic conditions) characteristic during the initial period of combustion for mineral inclusions, carbon merely adsorbs TE sulfides without chemical reactions. Yet TGA-DSC data showed that powdered graphite may react with TE sulfides in an oxidizing micro-environment (microaerobic conditions), such as those experienced during the later period of combustion for inclusions and during the entire combustion period for exclusions thus accelerating TE evolution without making qualitative changes in the vapor composition.

Thermal and transport properties of La2−xNdxMo2O9

Single-phase La2−xNdxMo2O9 (0≤x≤1.8) compounds were prepared using solid-state reaction technique. Their structural and thermal properties were characterized by room and high temperatures X-ray diffraction (XRD), thermo gravimetric analysis-differential scanning calorimetry (TG-DSC), and high temperature Raman spectra. The transport properties were investigated using D.C. four-probe technique and Hebb-Wagner polarization method. The substitution limit of Nb3+ in La2−xNdxMo2O9 was determined to be in the range of 1.8<x<1.9, and the cubic lattice parameter of La2−xNdxMo2O9 decreased linearly with the increasing of x. When the Nb3+ substitution content x was larger than 0.6, the α/β phase transition could be depressed to such a great degree that the phase transition thermal enthalpy was not detected by DSC. The temperature dependence of electrical conductivities for La1.4Nd0.6Mo2O9 below 873 K and that for LaNdMo2O9 below 923 K obeyed the Arrhenius law, while above 873 and 923 K Vogel-Tammann-Fulcher (VTF) model could describe the conduction behaviors satisfactorily. The transition of transport mechanism from Arrhenius to VTF was caused by the change of structure, which was supported by the high temperature XRD and Raman results. The ionic transport number of La1.4Nd0.6Mo2O9 in air was larger than 0.99 at 1073 K, and with the increasing of temperature it was close to 0.98 at 1173 K. In view of the phase transition, thermal expansion and conductivity properties, La1.4Nd0.6Mo2O9 should be a promising electrolyte material in La2−xNdxMo2O9 series.

Influence of Capping Ligand and Synthesis Method on Structure and Morphology of Aqueous Phase Synthesized CuInSe2 Nanoparticles

A facile route to synthesize copper indium diselenide (CuInSe2) nanoparticles in aqueous medium was developed using mercaptoacetic acid (MAA) as capping agent. Two different mole ratios (5 and 10) of MAA were used to synthesize CuInSe2 nanoparticles at room temperature, as well as hydrothermal (high temperature) method. Powder x-ray diffraction analysis reveals that the nanoparticles exhibit chalcopyrite phase and the crystallinity increases with increasing the capping ratio. Raman analysis shows a strong band at 233 cm−1 due to the combination of B2 (E) modes. Broad absorption spectra were observed for the synthesized CuInSe2 nanoparticles. The effective surface capping by MAA on the nanoparticles surface was confirmed through attenuated total reflection–Fourier transform infrared spectral analysis. The thermal stability of the synthesized samples was analyzed through thermogravimetric analysis–differential scanning calorimetry. The change in morphology of the synthesized samples was analyzed through scanning electron microscope and it shows that the samples prepared at room temperature are spherical in shape, whereas hydrothermally synthesized samples were found to have nanorod- and nanoflake-like structures. Transmission electron microscope analysis further indicates larger grains for the hydrothermally prepared samples with 10 mol ratio of MAA. Comparative analyses were made for synthesizing CuInSe2 nanoparticles by two different methods to explore the role of ligand and influence of temperature.

Effect of annealing on the structure and phase transformation in ZrO2–MgO ceramic powders

The structure and phase composition of ZrO2–MgO powders with the MgO content from 9 to 43 mol % obtained by the plasma chemical method after annealing at 700–1400°С are studied. Differential scanning calorimetry and powder thermogravimetric analysis are carried out. It is found that, in the course of heating, the mass loss and the endothermic reactions energy increase with the increase in the MgO content. In the initial state, the powders containing more than 25 mol % of MgO are supersaturated solid solutions of cubic ZrO2. Water desorption processes and decomposition of residual nitrates are observed in powders up to 420°С. The endothermic peak at high temperatures is due to the dehydration process and decomposition of the cubic ZrO2 solid solution.

One-pot template-free synthesis and highly ethanol sensing properties of ZnSnO3 hollow microspheres

ZnSnO3 hollow microspheres were synthesized by a simple one-pot template-free and general in-situ precipitation method combined with subsequent dehydration treatment. The prepared ZnSnO3 hollow microspheres were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the thermogravimetric-differential scanning calorimetry analysis (TG-DSC). The results showed that ZnSnO3 hollow microspheres with diameter ranging from 1.3 to 1.6μm were constructed by small nanoparticles with diameter of about 70nm. The investigation on the evolution formation revealed that the orientation and morphology of the products were carefully controlled by adjusting the amount of the addition of NaOH and the growth time, and a possible formation mechanism of the hollow structure was proposed. Moreover, the as-fabricated sensors based on the ZnSnO3 hollow microspheres showed superior gas-sensing properties for the detection of ethanol than ZnSnO3 solid spheres and can detect ethanol in the real life.

A Dual‐Characteristic Bidentate Ligand for a Ternary Mononuclear Europium(III) Molecular Complex – Synthesis, Photophysical, Electrochemical, and Theoretical Study

The new bipolar ligand 4‐{1‐(9,9‐diethyl‐9H‐fluoren‐2‐yl)‐1H‐imidazo[4,5‐f][1,10]phenanthrolin‐2‐yl}‐N,N‐diphenylbenzenamine (Phen‐Fl‐TPA) and its β‐diketonate EuIII complex have been designed, synthesized, characterized, and their photophysical and electrochemical properties have been investigated. The UV/Vis absorption and photoluminescence (PL) emission spectra of the Eu complex and Phen‐Fl‐TPA in solution as well as in the solid state and as thin films were recorded. The PL study indicated that the Eu complex emits narrow‐band red emission with an appropriate International Commission on Illumination (CIE) color gamut. Moreover, it also confirmed the efficient energy transfer from the ligand to the Eu3+ ion. Time‐dependent DFT (TD‐DFT) calculations were performed for the ligand to determine the exact positions of the excited singlet and triplet energy levels. The EuIII complex shows a dominant pathway involving energy transfer between the ligand triplet level and the excited (5D0) level of the EuIII ion. In addition, the theoretically calculated UV/Vis spectrum of the ligand is similar to the experimental one. The Judd–Ofelt theory was applied to the emissive properties of the EuIII complex, and the lifetime was found to be 0.66 ms. The ground‐state optimized ligand structure was a good match with the single‐crystal structure. The photoluminescence quantum yield (PLQY) of Eu(TTA)3Phen‐Fl‐TPA (TTA = thenoyltrifluoroacetone) in solution was 34.1 %, and it possess a high thermal decomposition temperature (317 °C), as determined by differential scanning calorimetry/thermogravimetric analysis (DSC‐TGA). Electrochemical analysis revealed highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels for the EuIII complex of 5.6 and 2.8 eV, respectively.

Potential recovery of phosphorus during the fluidized bed incineration of sewage sludge

Phosphorus is a limited non-renewable resource that is indispensable as an essential nutrient for the growth of organisms in most ecosystems. To demonstrate the reuse of phosphorus resources from sewage sludge ash (SSA), experiments were conducted in a pilot circulating fluidized bed kiln. The experimental results demonstrated that high temperature and calcium oxide (CaO) were beneficial for the transformation of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP). Thermogravimetric differential scanning calorimetry analysis was combined with X-ray diffraction measurements to simulate the process of sewage sludge incineration of the crystal phase transition between aluminium phosphate (AlPO4) and CaO, forming stable AP in the temperature range of 675–850 °C. Additionally, 89.29% of the phosphorus was enriched in sewage sludge bottom ash and 5.61% was distributed in fly ash, with AP being the primary component in the fly ash at 850 °C. AP content generally increased with decreasing particle size, whereas NAIP content exhibited the opposite tendency, and became stable when the particle size was less than 37.5 μm.

The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes

The extensive complementary experimental studies of the double metal catalysts (DMC) with two kinds of the organic ligands were performed. The chemical justification of the observed TG/DSC (thermogravimetric analysis/differential scanning calorimetry) steps was proposed. Several organic ligand complexing states were found in both types of catalysts. X-ray absorption spectroscopy (XAS) analysis established that only Zn atoms are the active metallic centers in DMC catalyst regardless the used ligand. Cl atoms were detected near some of Zn atoms. Contrary to the common suppositions no significant amount of oxygen atoms was detected in the closest coordination spheres of Zn.

Flexible Poly(Amide‐Imide)‐Carbon Black Based Microheater with High‐Temperature Capability and an Extremely Low Temperature Coefficient

Flexible poly(amide‐imide)‐carbon black (PAI‐CB) composite films, to be applied as high performance microheater foil, have been prepared with a solution/casting technique. The CB dispersion has been carefully controlled in order to improve the thermal and electrical properties of the resulting composites. Morphology and structure of the PAI‐CB composite films have been characterized by optical microscopy, atomic force microscopy and FTIR spectroscopy. The effect of the CB dispersion and its interaction with the polymer chains on the thermal and mechanical properties of the composite films have been investigated by using differential scanning calorimetry thermogravimetric analysis and dynamic mechanical analysis. The electrical characterization has evidenced high‐temperature capability and an extremely low temperature coefficient of the electrical resistance. An excellent ohmic behavior of the electrical characteristics and a fast on/off‐switching of the heater‐foil have also been found. No mechanical and electrical changes of the polymeric heater have been observed after various mechanical bending cycles. The combination of the observed electrical and thermal properties allows the realization of stable, compact, and flexible electrical heating systems.

Improved electrochemical performance of 5 V spinel LiNi0.5Mn1.5O4 microspheres by F-doping and Li4SiO4 coating

Porous spinel LiNi0.5Mn1.5O4 microspheres were synthesized by a co-precipitation method. F-doping and Li4SiO4-coating were used as two effective ways to enhance the electrochemical performance of LiNi0.5Mn1.5O4 at both room temperature and elevated temperature. All the samples were characterized by thermogravimetric analysis/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), inductive coupled plasma-atomic emission spectroscopy (ICP-AES), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical tests, respectively. According to the SEM images, the LiNi0.5Mn1.5O4 microspheres are hollow with porous shell, and each microsphere is made up of nano-sized spinel grains. This hollow and porous structure favors the sufficient contact between electrolyte and the cathode material. It is indicated that 2 wt.% Li4SiO4-coated LiNi0.5Mn1.5O3.98F0.02 exhibits more superior performance than the pristine one. The doped fluorine ions that enhance the bonding can stabilize the structure of cathode material. The Li4SiO4 coating can suppress side reactions between electrolyte and cathode material as a protective material, and it is a superionic conductor with a three-dimensional lithium ion transfer network to decrease the charge-transfer resistance. The discharge capacity retention of 2 wt.% Li4SiO4-coated LiNi0.5Mn1.5O3.98F0.02 is 97.8% at 25 °C and 94.2% at 55 °C after 150 cycles, respectively.

Characterization of corrosion scale formed on 3Cr steel in CO2-saturated formation water

The evolution of the corrosion scale formed on 3Cr steel was investigated by scanning electron microscopy (SEM) and X-Ray Diffraction (XRD). The inner layer was characterized by Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis-differential scanning calorimetry (TG-DSC). The results show the inner layer is an amorphous-like structure containing some nano-quasicrystalline and nanocrystalline grains which is more uniform and less porous than the crystalline FeCO3 layer. At the 2nd stage, the transition of cathodic reactions was found, and the growth of the FeCO3 phase in the inner layer dramatically decreased the film porosity, resulting in the passivation.

Effects of Ultrasound on the Physicochemical Properties and Antioxidant Activities of Chestnut Polysaccharide

Abstract A comparison of chestnut polysaccharide extraction using ultrasound-assisted extraction (UAE) and hot water extraction (HWE) demonstrated that UAE is superior to HWE due to its higher extraction efficiency. Scanning electron microscopy (SEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the ultrasound-assisted-extracted polysaccharide (UAEP) and hot water-extracted polysaccharide (HWEP). SEM images revealed that the UAEP and chestnut residue were crushed, with particle sizes that were smaller than those of the HWEP, which was related to the breakage of long-chain polysaccharides. TGA-DSC showed a higher transition temperature and enthalpy value for the UAEP than the HWEP, and the FTIR spectrum revealed typical characteristics of polysaccharides, with some differences between the UAEP and HWEP. The evaluation of antioxidant activities showed that the UAEP had stronger antioxidant capacities than the HWEP, regardless of the reducing power and DPPH-, ABTS- and hydroxyl radical-scavenging activities, suggesting that ultrasound is an optimal method to rapidly extract chestnut polysaccharide, a potential natural antioxidant.