Synthesis,structure, and thermo‐physical properties of Fe2O3.Al2O3 and polyethylene nanocomposites

In this study, Fe₂O₃.Al₂O₃/polyethylene composites were prepared using a two‐step process. In the first step, PE is synthesized using titanium based metallocene catalyst system. While the synthesized PE was subsequently purified, hydrated alumina filled PE (MHFP) composites was formed by the hydrolysis of methylaluminoxane (MAO). In the second step, Fe₂O₃.Al₂O₃/PE was prepared via thermal decomposition of ferric formate in a high temperature solution of MHFP composite. The structure, morphology, and thermal properties of the composites were characterized using the XRD, FTIR, SEM‐EDX, TGA, and DSC analytical techniques. Results showed that the incorporation of a suitable amount of Fe₂O₃.Al₂O₃ into the composites enhances the thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of nano‐reinforced thermal conductive natural rubber composites

Natural rubber (NR) composites highly filled with nano‐α‐alumina (nano‐α‐Al₂O₃) modified in situ by the silane coupling agent bis‐(3‐triethoxysilylpropyl)‐tetrasulfide (Si69) were prepared. The effects of various modification conditions and filler loading on the properties of the nano‐α‐Al₂O₃/NR composites were investigated. The results indicated that the preparation conditions for optimum mechanical (both static and dynamic) properties and thermal conductivity were as follows: 100 phr of nano‐α‐Al₂O₃, 6 phr of Si69, heat‐treatment time of 5 min at 150°C. Furthermore, two other types of fillers were also investigated as thermally conductive reinforcing fillers for the NR systems: (1) hybrid fillers composed of 100 phr of nano‐α‐Al₂O₃ and various amounts of the carbon black (CB) N330 and (2) nano‐γ‐Al₂O₃, the particles of which are smaller than those of nano‐α‐Al₂O₃. The hybrid fillers had better mechanical properties and dynamic performance with higher thermal conductivity, which means that it can be expected to endow the rubber products serving under dynamic conditions with much longer service life. The smaller sized nano‐γ‐Al₂O₃ particles performed better than the larger‐sized nano‐α‐Al₂O₃ particles in reinforcing NR. However, the composites filled with nano‐γ‐Al₂O₃ had lower thermal conductivity than those filled with nano‐α‐Al₂O₃ and badly deteriorated dynamic properties at loadings higher than 50 phr, both indicating that nano‐γ‐Al₂O₃ is not a good candidate for novel thermally conductive reinforcing filler. POLYM. COMPOS., 37:771–781, 2016. © 2014 Society of Plastics Engineers     

Chitosan‐Tethered Iron Oxide Composites as an Antisintering Porous Structure for High‐Performance Li‐Ion Battery Anodes

Chitosan‐linked Fe₃O₄ (CL‐Fe₃O₄) is facilely prepared by electrostatic interactions between citrate‐capped Fe₃O₄ (C‐Fe₃O₄) (with negatively charged carboxylate groups) and chitosan oligosaccharide lactate (with positively charged amine groups), and utilized as anodes for lithium‐ion batteries. Inert‐atmosphere calcination of CL‐Fe₃O₄ at 400°C leads to the formation of chitosan‐tethered iron oxide composites (Fe₂O₃@chitosan) with an antisintering porous structure. As the calcination temperature changes from 400°C to 700°C, the size of primary particles increases from ca. 40 nm to ca. 100 nm, and the surface area decreases from 57.8 m²/g to 10.9 m²/g. The iron oxide composites exhibit a high discharge capacity and good rate performance. At a current density of 0.1 C after 50 cycles, Fe₂O₃@chitosan (400°C) exhibits a higher retention capacity of 732 mAh/g than those (544 and 634 mAh/g) of chitosan‐free Fe₂O₃ and Fe₂O₃@chitosan (700°C), respectively. The high performance of Fe₂O₃@chitosan (400°C) is attributed to the antisintering porous structure with high surface area that is beneficial for facilitating ion transport, demonstrating a useful chemical strategy for the direct formation of porous electrode materials at low calcination temperature.     

The crystallization,thermal and mechanical properties of nano‐Sb2O3 filled poly(butylene terephthalate)

Nano‐Sb₂O₃ particles were modified by a combination modifier of cetyltrimethyl ammonium bromide (CTAB) and KH‐560 via the mechanochemical method based on high‐energy ball milling. Then, the testing specimens of the nano‐Sb₂O₃/PBT composites of differing compositions were prepared by melting blending technology. The crystallization, thermal, and mechanical properties of composites were characterized by X‐ray diffraction, differential scanning calorimetry, thermogravimetric analyzer, and mechanical performance test. The tensile and impact fracture surfaces of composites were determined by scanning electron microscopy. Besides, the influence of the Sb₂O₃ nanoparticles surface modification on crystallinity, mechanical properties of the composites, and the interfacial adhesion between nano‐Sb₂O₃ and PBT was systematically investigated. The results indicate that the main crystalline characteristics of PBT matrix remain unchanged in the nanocomposites. However, the addition of nano‐Sb₂O₃ particles plays a heterogeneous nucleation and can effectively improve the crystallization of PBT matrix. In addition, the compound modification of the nano‐Sb₂O₃ can effectively enhance mechanical properties of the composites and interfacial interaction between nano‐Sb₂O₃ and PBT. The enhanced fracture properties in the nanocomposites were caused by the assisted void formation at the edge of the nano‐Sb₂O₃ particle. When the nano‐Sb₂O₃ mass fraction is 3%, the composites show excellent comprehensive performance. The interfacial adhesion parameter B and the half‐debonding angle θ of composites were assessed to quantitatively characterize the interfacial adhesion strength between nano‐Sb₂O₃ and PBT. Finally, the reinforcement and toughening mechanisms were described. J. VINYL ADDIT. TECHNOL., 26:268–281, 2020. © 2019 Society of Plastics Engineers     

Chemical synthesis,characterization, and direct‐current conductivity studies of polypyrrole/γ‐Fe2O3 composites

The in situ polymerization of pyrrole was carried out in the presence of γ‐Fe₂O₃ to synthesize polypyrrole/γ‐Fe₂O₃ composites by a chemical oxidation method. The polypyrrole/γ‐Fe₂O₃ composites were synthesized with various compositions, including 10, 20, 30, 40, and 50 wt % γ‐Fe₂O₃ in pyrrole. The polypyrrole/γ‐Fe₂O₃ composites were characterized with X‐ray diffractometry and infrared spectroscopy. The surface morphology of these composites was studied with scanning electron microscopy. The direct‐current conductivity was studied from 40 to 200°C. The dimensions of the γ‐Fe₂O₃ particles in the matrix had a greater influence on the conductivity values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2797–2801, 2007     

Anthranilic acid assisted preparation of Fe3O4–poly(aniline‐co‐o‐anthranilic acid) nanoparticles

Magnetic Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were prepared by a novel and simple method: anthranilic acid assisted polymerization. The synthetic strategy involved two steps. First, Fe₃O₄ nanoparticles capped by anthranilic acid were obtained by a chemical precipitation method, and then the aniline and oxidant were added to the modified Fe₃O₄ nanoparticles to prepare well‐dispersed Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles. Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles exhibited a superparamagnetic behavior (i.e., no hysteresis loop) and high‐saturated magnetization (M_s = 21.5 emu/g). The structure of the composite was characterized by Fourier‐transform infrared spectra, X‐ray powder diffraction patterns, and transmission electron microscopy, which proved that the Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were about 20 nm. Moreover, the thermal properties of the composite were evaluated by thermogravimetric analysis, and it showed excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1666–1671, 2006     

Thermal Decomposition,Kinetics and Compatibility Studies of Poly(3‐difluoroaminomethyl‐3‐methyloxetane) (PDFAMO)

The thermal decomposition of poly(3‐difluoroaminomethyl‐3‐methyloxetane) (PDFAMO) with an average molecular weight of about 6000 was investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The kinetics of thermolysis were studied by a model‐free method. The thermal decomposition of PDFAMO occurred in a two‐stage process. The first stage was mainly due to elimination of HF and had an activation energy of 110–120 kJ mol⁻¹. The second stage was due to degradation of the polymer chain. The Fourier transform infrared (FTIR) spectra of the degradation residues showed that the difluoroamino groups decomposed in a two‐step HF loss at different temperatures. The remaining monofluoroimino groups produced by the incomplete elimination of HF were responsible for the two‐stage thermolysis process. The compatibility of PDFAMO with some energetic components and inert materials used in polymer‐bonded explosives (PBXs) and solid propellants was studied by DSC. It was concluded that the binary systems of PDFAMO with cyclotrimethylenetrinitramine (RDX), 2,4,6‐trinitrotoluene (TNT), 2,4‐dinitroanisole (DNAN), pentaerythritol tetranitrate (PETN), ammonium perchlorate (AP), aluminum powder (Al), aluminum oxide (Al₂O₃) and 1,3‐diethyl‐1,3‐diphenyl urea (C₁) were compatible, whereas the systems of PDFAMO with lead carbonate (PbCO₃) and 2‐nitrodiphenylamine (NDPA) were slightly sensitized. The systems with cyclotetramethylenetetranitroamine (HMX), hexanitrohexaazaisowurtzitane (CL‐20), 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), ammonium nitrate (AN), magnesium powder (Mg), boron powder (B), carbon black (C. B.), diphenylamine (DPA), and p‐nitro‐N‐methylamine (PNMA) were incompatible. The results of compatibility studies fully supported the suggested thermal decomposition mechanism of PDFAMO.     

Fabrication of Fe3O4/PLLA composites for use in bone tissue engineering

The aim of this study was to incorporate nanoscale Fe₃O₄ particles into a poly‐l ‐lactide (PLLA) matrix to fabricate a magnetic and biodegradable composite. The physical and osteogenic functions of this material were tested. Injection molding was used to fabricate four nano‐Fe₃O₄/PLLA composites with Fe₃O₄ mix ratios of 0%, 20%, 30%, and 40% (w/w). X‐ray diffraction and hysteresis loop tests were performed to evaluate the physical properties of the nano‐Fe₃O₄/PLLA composites. Tensile strength tests showed that the progressive addition of nano‐Fe₃O₄ particles to the PLLA matrix results in higher elastic modulus and lower tensile strength. Images from scanning electron microscopy demonstrated that osteoblasts cultured on the 20% nano‐Fe₃O₄/PLLA surface exhibited abundant filaments, which are a morphologic characteristic of osteoblastic differentiation. These results suggest that the 20% nano‐Fe₃O₄/PLLA composite used in this study has the potential for future tissue engineering applications. POLYM. COMPOS., 38:2881–2888, 2017. © 2016 Society of Plastics Engineers     

Magnetic property,thermal stability,UV‐resistance,and moisture absorption behavior of magnetic wood composites

Magnetic wood composites with improved anti‐ultraviolet property and dimensional stability were prepared by modification with iron oxides (Fe₃O₄/γ‐Fe₂O₃) via a facile one‐step hydrothermal method using ferric trichloride and ferrous chloride as the precursors at 90°C. The morphology, crystalline phase, and chemical structure of the wood composites before and after hydrothermal process were characterized by scanning electron microscope, transmission electron microscope, X‐ray diffraction, Raman spectroscopy, and Fourier transformation infrared spectroscopy (FTIR). The results indicated that the magnetic nanoparticles precipitated on the wood substrate by adhesion to wood surface in the form of aggregates. A possible hydrothermal fabrication mechanism was proposed. After hydrothermal treatment, the magnetic wood composites exhibited appropriate magnetic and anti‐ultraviolet properties. Thermal analysis showed that the incorporation of magnetic nanoparticles retarded the thermal decomposition of wood matrix and improved the thermal stability of wood. Moreover, the dimensional stability of the modified wood materials was also evaluated. POLYM. COMPOS., 38:1646–1654, 2017. © 2015 Society of Plastics Engineers     

Synergistic effects of nano‐Mn0.4Zn0.6Fe2O4 on intumescent flame‐retarded polypropylene

The melamine salt of 5,5‐dimethyl‐1,3,2‐dioxaphos‐phorinane‐2‐oxide‐2‐hydroxide (IFR100) was used as an intumescent flame retardant in flame‐retarded polypropylene (PP). As a synergistic agent, nano‐Mn_0.4Zn_0.6Fe₂O₄ was incorporated into the PP/IFR100 composite at different proportions. The synergistic effects of nano‐Mn_0.4Zn_0.6Fe₂O₄ were studied by the limiting oxygen index (LOI) test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD). The synergistic effect of the nano‐Mn_0.4Zn_0.6Fe₂O₄ additive with IFR100 was clearly observed by LOI. The TGA results showed that nano‐Mn_0.4Zn_0.6Fe₂O₄ improved the thermal stability of the PP/IFR100 system above 400°C. On the basis of the FTIR and XRD results, it was evident that nano‐Mn_0.4Zn_0.6Fe₂O₄ efficiently promoted the formation of a charred layer containing phosphocarbonaceous structures. The SEM micrographs indicated that nano‐Mn_0.4Zn_0.6Fe₂O₄ strengthened the structure of the char layer remaining after combustion. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers     

Development of highly reinforced maleated natural rubber nanocomposites based on sol–gel‐derived nano alumina

In the present study, sol–gel synthesized alumina (Al₂O₃) nanoparticles were characterized by Fourier transform infrared spectra, X‐ray diffraction, field‐emission scanning electron microscopy. Then, Al₂O₃ nanoparticles were employed to improve cure, mechanical, and thermal properties of maleated natural rubber (MNR) nanocomposites. The MNR nanocomposite with 2 phr nano Al₂O₃ exhibited excellent value of cure rate index and exceptionally high value of mechanical properties like modulus and tensile strength in comparison to unfilled MNR compound. Thermogravimetric analysis indicated that nano Al₂O₃ was able to improve the thermal stability of MNR composites to some extent. Additionally, the present study revealed that the interfacial interaction between MNR and nano Al₂O₃ was far better than that between NR and nano Al₂O₃ as confirmed from crosslinking degree measurement and morphological analysis. The present article offers a fresh approach to prepare high performance nano Al₂O₃‐based MNR compounds for future industrial application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46248.     

Magnetic and conducting Fe3O4–polypyrrole nanoparticles with core‐shell structure

Magnetic and conducting Fe₃O₄–polypyrrole nanoparticles with core‐shell structure were prepared in the presence of Fe₃O₄ magnetic fluid in aqueous solution containing sodium dodecylbenzenesulfonate (NaDS) as a surfactant and dopant. Both the conductivity and magnetization of the composites depend strongly on the Fe₃O₄ content and the doping degree. With increase of Fe₃O₄ content in the composite, the conductivity at room temperature decreases, but the saturated magnetization and coercive force increase. Transmission electron microscopy (TEM) images of Fe₃O₄ and Fe₃O₄–polypyrrole particles show almost spherical particles with diameters ranging from 20 to 30 and 30 to 40 nm, respectively. The thermal stability of Fe₃O₄–polypyrrole composites is higher than that of pure polypyrrole. Studies of IR, UV–visible and X‐ray photoelectron spectroscopy (XPS) spectra suggest that the increased thermal stability may be due to interactions between Fe₃O₄ particles and polypyrrole backbone. Copyright © 2003 Society of Chemical Industry     

Novel electrically conductive and ferromagnetic composites of poly(aniline‐co‐aminonaphthalenesulfonic acid) with iron oxide nanoparticles: Synthesis and characterization

Nanocomposites of iron oxide (Fe₃O₄) with a sulfonated polyaniline, poly(aniline‐co‐aminonaphthalenesulfonic acid) [SPAN(ANSA)], were synthesized through chemical oxidative copolymerization of aniline and 5‐amino‐2‐naphthalenesulfonic acid/1‐amino‐5‐naphthalenesulfonic acid in the presence of Fe₃O₄ nanoparticles. The nanocomposites [Fe₃O₄/SPAN(ANSA)‐NCs] were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, elemental analysis, UV–visible spectroscopy, thermogravimetric analysis (TGA), superconductor quantum interference device (SQUID), and electrical conductivity measurements. The TEM images reveal that nanocrystalline Fe₃O₄ particles were homogeneously incorporated within the polymer matrix with the sizes in the range of 10–15 nm. XRD pattern reveals that pure Fe₃O₄ particles are having spinel structure, and nanocomposites are more crystalline in comparison to pristine polymers. Differential thermogravimetric (DTG) curves obtained through TGA informs that polymer chains in the composites have better thermal stability than that of the pristine copolymers. FTIR spectra provide information on the structure of the composites. The conductivity of the nanocomposites (～ 0.5 S cm^?1) is higher than that of pristine PANI (～ 10^?3 S cm^?1). The charge transport behavior of the composites is explained through temperature difference of conductivity. The temperature dependence of conductivity fits with the quasi‐1D variable range hopping (quasi‐1D VRH) model. SQUID analysis reveals that the composites show ferromagnetic behavior at room temperature. The maximum saturation magnetization of the composite is 9.7 emu g^?1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Burning Characteristics of Ammonium Nitrate‐Based Composite Propellants Supplemented with Fe2O3

Ammonium nitrate (AN)‐based composite propellants have attracted a considerable amount of attention because of the clean burning nature of AN as an oxidizer. However, such propellants have several disadvantages such as poor ignition and a low burning rate. In this study, the burning characteristics of AN‐based propellants supplemented with Fe₂O₃ as a burning catalyst were investigated. The addition of Fe₂O₃ is known to improve the ignitability at low pressure. Fe₂O₃ addition also increases the burning rate, while the pressure exponent generally decreases. The increasing ratio (R) of the burning rate of the AN/Fe₂O₃ propellant to that of the corresponding AN propellant vs. the amount of Fe₂O₃ added (ξ) depends on the burning pressure and AN content. R decreases at threshold value of ξ. The most effective value of ξ for increasing the burning rate was found to be 4 % for the propellant at 80 % AN, and the value generally decreased with decreasing AN content. According to thermal decomposition kinetics, Fe₂O₃ accelerates the reactions of AN and binder decomposition gases in the condensed‐ and/or gas‐phase reaction zones. The burning characteristics of the AN‐based propellant were improved by combining catalysts with differing catalytic mechanisms instead of supplementing the propellant with a single catalyst owing to the multiplicative effect of the former.     

Effect of Nano‐Copper Oxide and Copper Chromite on the Thermal Decomposition of Ammonium Perchlorate

The catalytic effect on the thermal decomposition behavior of ammonium perchlorate (AP) of p‐type nano‐CuO and CuCr₂O₄ synthesized by an electrochemical method has been investigated using differential scanning calorimetry as a function of catalyst concentration. The nano‐copper chromite (CuCr₂O₄) showed best catalytic effects as compared to nano‐cupric oxide (CuO) in lowering the high temperature decomposition by 118 °C at 2 wt.‐%. High heat releases of 5.430 and 3.921 kJ g⁻¹ were observed in the presence of nano‐CuO and CuCr₂O₄, respectively. The kinetic parameters were evaluated using the Kissinger method. The decrease in the activation energy and the increase in the rate constant for both the oxides confirmed the enhancement in catalytic activity of AP. A mechanism based on an electron transfer process has also been proposed for AP in the presence of nano‐metal oxides.     

Carboxyl‐containing polyarylene ether nitrile/Fe3O4 hybrids and their effects on the PEN composites

In this study, the novel polyarylene ether nitrile containing carboxyl groups (CPEN)/Fe₃O₄ hybrids were synthesized via the solvent‐thermal route. The SEM and TEM images showed that the surface of functionalized Fe₃O₄ hybrids (CPEN‐f‐Fe₃O₄) became rough and coated with a thin polymer layer successfully. Chemical bonds were formed between the carboxyl groups and Fe₃O₄ spheres, which were characterized by FTIR and XRD. Series of PEN composite films were prepared through solution‐casting method with different contents of CPEN‐f‐Fe₃O₄ hybrids and raw Fe₃O₄ spheres. The SEM images showed that the CPEN‐f‐Fe₃O₄ hybrids became much more dispersible and compatible in PEN matrix than that of raw Fe₃O₄ spheres, which was further confirmed by rheological study. The magnetic analysis showed that the saturation magnetization of composites films increased with the increase of CPEN‐f‐Fe₃O₄ hybrids loading content. The results of thermogravimetric and mechanical study exhibited that the composite films had good thermal stability and mechanical property. POLYM. COMPOS., 36:1325–1334, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of polyimide‐γ‐Fe2O3 nanocomposites

Novel polyimide‐γ‐Fe₂O₃ hybrid nanocomposite films (PI/γ‐Fe₂O₃) has been developed from the poly(amic acid) salt of oxydianiline with different weight percentages (5, 10, 15 wt %) of γ‐Fe₂O₃ using tetrahydrofuran (THF) and N,N‐dimethylacetamide (DMAc) as aprotic solvents. The prepared polyimide‐γ‐Fe₂O₃ nanocomposite films were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), transmission electron micrograph (TEM), X‐ray diffraction (XRD), ¹³C‐NMR, and thermal analysis (TGA/DSC) techniques. These studies showed the homogenous dispersion of γ‐Fe₂O₃ in the polyimide matrix with an increase in the thermal stability of the composite films on γ‐Fe₂O₃ loadings. Magnetization measurements (magnetic hysteresis traces) have shown very high values of coercive force indicating their possible use in memory devices and in other related applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 834–840, 2007     

Simultaneously enhanced mechanical properties and thermal properties of ultrahigh‐molecular‐weight polyethylene with polydopamine‐coated α‐alumina platelets

Polydopamine (PDA) was employed to modify micrometric Al₂O₃ platelets to improve the interfacial compatibility between α‐Al₂O₃ powder and ultrahigh‐molecular‐weight polyethylene (UHMWPE). The structure of PDA‐coated Al₂O₃ and UHMWPE composites was investigated via Fourier transform infrared spectroscopy, scanning electron microscopy and X‐ray photoelectron spectroscopy. The thermal stability and mechanical performance of the samples were also evaluated. It is clear that UHMWPE/PDA‐Al₂O₃ composites exhibit better mechanical properties, higher thermal stability and higher thermal conductivity than UHMWPE/Al₂O₃ composites, owing to the good dispersion of Al₂O₃ powder in the UHMWPE matrix and the strong interfacial force between the macromolecules and the inorganic filler caused by the presence of PDA. The tensile strength and the tensile elongation at break of UHMWPE/PDA‐Al₂O₃ composite with 1 wt% PDA‐Al₂O₃ are 62.508 MPa and 462%, which are 1.96 and 1.98 times higher than those of pure UHMWPE, respectively. The thermal conductivity of UHMWPE/PDA‐Al₂O₃ composite increases from 0.38 to 0.52 W m^?1 K^?1 with an increase in the dosage of PDA‐Al₂O₃ to 20 wt%. The results show that the prepared PDA‐coated Al₂O₃ powder can simultaneously enhance the mechanical properties and thermal conductivity of UHMWPE. © 2018 Society of Chemical Industry     

Fabrication,characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites

Poly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe₃O₄) nanocomposite was prepared with different loading of Fe₃O₄ nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe₃O₄‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe₃O₄ nanoparticle at higher loading. The presence of Fe₃O₄ nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40116.     

Differential Scanning Calorimetric Study of HTPB based Composite Propellants in Presence of Nano Ferric Oxide

A comparative study of the thermal decomposition of ammonium perchlorate (AP)/hydroxy terminated polybutadiene (HTPB) based composite propellants has been carried out in presence and absence of nano iron oxide at different heating rates in a dynamic nitrogen atmosphere using differential scanning calorimetry. The pronounced effect was a lowering of the high temperature decomposition by 49 °C. A higher heat release up to 40% was observed in presence of nano ferric oxide (3.5 nm). The kinetic parameters were evaluated using the Kissinger method. The increase of the rate constant in the catalyzed propellant confirmed the enhancement of the catalytic activity of ammonium perchlorate. The scanning electron micrographs of nano Fe₂O₃ incorporated in HTPB revealed a well‐separated characteristic necklace‐like structure of α‐Fe₂O₃ particles at high magnification.