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Flexible high-loading nanoparticle-reinforced polyurethane magnetic nanocomposites fabricated by the surface-initiated polymerization (SIP) method are reported. Extensive field emission scanning electron microscopic (SEM) and atomic force microscopic (AFM) observations revealed a uniform particle distribution within the polymer matrix. X-ray photoe...
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... method utilizes physicochemically adsorbed moisture (as seen from the FT-IR spectrum in figure 4) on the nanoparticles as a linking site between the nanoparticle and polymer chain. Figure 1 illustrates the entire SIP process. The nanoparticles were added into the catalyst and THF promoter solution. ...
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... nanoparticles were added into the catalyst and THF promoter solution. The above nanoparticle suspended solution was then sonicated for about 30 min ( figure 1, step 1). The sonication energy should enhance the reactivity of the surface and promote the adsorption of catalyst and promoter onto the nanoparticle surface while evaporating the physically adsorbed moisture. ...
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... a result, the intensity of the peak at 527.5 eV for the Fe-O-Fe contribution was observed to increase dramatically. The absorbed catalyst accelerator (CA) by the nanoparticles was observed to have a significant effect on the thermal stability of the nanoparticles as shown in figure 1 of the TGA analysis. The intensity of the Fe-O- Fe decreased after the polymerization in solution, which is due to the polyurethane coating on the nanoparticle surface. ...
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... effect of the polymer matrix on the magnetic property of the nanoparticles was investigated in a 9 T physical properties measurement system by Quantum Design. Figure 10 shows the hysteresis loops of the pure as-received Fe 2 O 3 nanoparticles and the SIP Fe 2 O 3 /PU nanocomposites with a loading of 65 wt%, respectively. The observed non-zero values of the coercive force (coercivity, H c ) in both the as-received nanoparticles and the polymeric nanocomposite indicate the ferromagnetic state. ...
Citations
... 45,46 Thus, increased interparticle distance in the composite reduces the interparticle dipolar interactions, resulting in higher Hc values. 9,47 The higher coercivity of the composites can be further explained by ARTICLE pubs.aip.org/aip/adv using the concept of shape anisotropy. Without the presence of a polymer matrix, the bare nanoparticles usually form aggregates that are more or less equiaxed in overall shape. ...
In this research, we synthesize composites of CoxMg1−xFe2O4 (0 ≤ x ≤ 1) spinel nano-ferrites and polybenzoxazine (PBZ) and characterize their structural, optical, and magnetic properties. The magnetic nanoparticles are fabricated using the chemical co-precipitation method. The benzoxazine (BZ) monomer is synthesized by Mannich condensation reaction using aniline, paraformaldehyde, and phenol. Specific weights of the ferrite particles and BZ monomer are then mixed and thermally treated to produce the composites. X-ray diffraction (XRD) ensures that the desired spinel phase is formed. Moreover, the average crystallite size calculated from the XRD data ranges from 5.3 to 15.5 nm, which shows a fair degree of agreement with the transmission electron microscope images. Energy dispersive x-ray spectroscopy has confirmed the chemical composition of the samples. Fourier transform infrared characterization has been used to confirm the formation of BZ and PBZ. The magnetic properties at room temperature are evaluated using a vibrating sample magnetometer. Increasing the cobalt content has increased the saturation magnetization (Ms) significantly in the ferrite samples while creating composites with PBZ decreased the Ms values. We find that the coercivity (Hc) of the composites has increased more than that of the bare ferrite particles. The optical properties are evaluated by ultraviolet–visible spectrophotometry (UV–Vis) analysis, where it is found that the optical bandgap increases with an increase in the Mg component. Higher retention of the magnetic properties in the composite, especially coercivity (Hc), shows potential for applications that require high magnetic properties in combination with structural flexibility.
... From previous experience [26,48], an inferior level of filler dispersion is expected from the beginning of the experiment, as a simple oxide filler is purposefully used without any surface treatment. It is of course possible to apply a surface treatment for better particle dispersion [49][50][51], but the relatively high viscosity (related to the polymer molecular weight) of the base material is more important in this case [52,53]. On the other hand, the high viscosity (up to 6000 mPa·s) can also have a positive effect, especially in preventing sedimentation [54] of the filler during the curing process, which proceeds for a relatively long time at ambient temperature. ...
Recently, polyurethanes (PURs) have become a very promising group of materials with considerable utilization and innovation potential. This work presents a comprehensive analysis of the changes in material properties important for PUR applications in the electrical industry due to the incorporation of magnesium oxide (MgO) nanoparticles at different weight ratios. From the results of the investigations carried out, it is evident that the incorporation of MgO improves the volume (by up to +0.5 order of magnitude) and surface (+1 order of magnitude) resistivities, reduces the dielectric losses at higher temperatures (−62%), improves the thermal stability of the material, and slows the decomposition reaction of polyurethane at specific temperatures (+30 °C). In contrast, the incorporation of MgO results in a slight decrease in the dielectric strength (−15%) and a significant decrease in the mechanical strength (−37%).
... To address those issues, researchers are involved in the development of bio-derived sustainable PU composites with improved performance [8,12]. A considerable attention has been made to develop carbon nanomaterials based PU nanocomposites as it can effectually increase the mechanical, electrical, and physicochemical properties of the resultant materials [13][14][15][16][17]. Among all used carbon nanomaterials, graphene oxide (GO) has drawn a great attention due to the existence of different functional groups on its surface, large surface area, water dispersibility and remarkable thermo-mechanical properties [18]. ...
Herein, we report the fabrication of [email protected]α-MnO2/[email protected]δ-MnO2 nanohybrid containing bio-derived water dispersed polyurethane (PU) nanocomposite (PUNH). Three nanocomposites of PU were fabricated with 0.5, 1.0 and 1.5 weight percentages of [email protected]α-MnO2/[email protected]δ-MnO2 and characterized by using various techniques including FTIR, XRD, BET, CV, FESEM, and TEM. Thermo-mechanical properties of PUNHs increase with the increase of nanohybrid content in the pristine PU. Chemical resistance and UV-aging capabilities of PUNHs increase, whereas biodegradation of them decreases with the increase of nanohybrid concentration in the pristine PU. The catalytic activities as well as anticorrosive performance of the nanocomposite were found to be excellent. PUNH1.5 showed proficient catalytic efficiency for the synthesis of N-(4-nitrobenzylidene)aniline with high yield (∼ 83 %). The used nanocomposite was recycled for five times without significant loss of activity. Furthermore, PUNH1.5 showed favorable corrosion current density (9.64 × 10⁻⁹A/cm²), corrosion potential (-0.318 V) and corrosion rate of 5.98 × 10⁻⁴ mm/yr after 8 days of exposure in 3.5 weight percentage NaCl aqueous solution.
... Arc discharge, chemical vapour deposition, laser pyrolysis, microwave plasma, metal-catalysed methods and metallic reduction-pyrolysis-catalysis are some of the processing methods have been deployed [21][22][23][24][25][26]. However these processes typically have drawbacks due to complexity and high energy costs. ...
... Different carbon sources have been used for the production of carbon-based magnetic nano-structures including acetylene, oleates, acetate, low density polyethylene, yeast alcohol dehydrogenase, polyurethane and nitro-phenol [24,[31][32][33][34][35][36][37][38]. An attractive feature of using carbon based materials in conjunction with magnetic nanoparticles is the possibility of using renewable biomass as raw material. ...
... Guo et. al, used two different approaches for the fabrication of magnetic nano-composites conventional direct sonication and surface initiated polymerization sonication using similar quantities of chemicals [24]. In the conventional direct sonication method, monomers, catalyst and accelerator were added with ultrasonic stirring for half an hour. ...
... In recent years, the growing development of both electrospinning technique and polymeric materials has significantly increased the production of hybrid, or simply composite, electrospun nanofibers embedding organic and/or inorganic fillers in order to improve their functionality for biomedical or microelectronic applications [1][2][3][4][5][6]. In particular, magnetically functionalized nanofibers (MFNs), namely polymer based fibers incorporating magnetic nanoparticles (MNPs), are attracting increasing interest due to their potential use in micro-electro-mechanical devices, magnetic recording, ferrofluids, sensors, microwave absorption [7][8][9][10][11] and biomedical applications -i.e. bone repair [12][13][14], tissue engineering [15,16], magnetic hyperthermia [17], contrast agent and imaging techniques [18][19][20], controlled drug release [21] and drug delivery [22]. ...
Electrospinning technique has been successfully used to produce composite nanofibers combining magnetic nanoparticles with polymer matrices. Process conditions to assembly nanofibers in tubular systems, as well as their morphological and elastomagnetic properties, have been explored. A volume percentage of magnetic charge close to 30% has been achieved. The optimization of the fabrication method ensures that the particles are completely covered by a thin polymer shell, so safe-guarding bio-compatibility. In particular, the deformation induced by the direct elastomagnetic effect, applying a static or a pulsed magnetic field, has been investigated. Resultant devices exhibit good elastomagnetic stretchability at room temperature-longitudinal relative strain/exciting field ~4·10–3/(1.5·10⁴ A/m) –, thus suggesting their potential use for applications in biomedical field as magneto-active components, as well as sensors and actuators.
... All TPUs demonstrate a tensile strength near or above 10 MPa, an oft-considered benchmark value for practical applications. For comparison, these TPUs demonstrate tensile strengths comparable to or even higher than a class of polyurethane composites reinforced with high loading of filler particles [49], where tensile strengths were found in the range of 9 MPa and 11 MPa. We point out that, despite the relatively high degree of crystallinity in the soft and hard segments, these TPUs display high degree of elongations. ...
Novel fast response shape-memory polyurethanes were prepared from bio-based polyols, diphenyl methane diisocyanate and butane diol for the first time. The bio-based polyester polyols were synthesized from 9-hydroxynonanoic acid, a product obtained by ozonolysis of fatty acids extracted from soy oil and castor oil. The morphology of polyurethanes was investigated by synchrotron ultra-small angle X-ray scattering, which revealed the inter-domain spacing between the hard and soft phases, the degree of phase separation, and the level of intermixing between the hard and soft phases. We also conducted thorough investigations of the thermal, mechanical, and dielectric properties of the polyurethanes, and found that high crystallization rate of the soft segment gives these polyurethanes unique properties suitable for shape-memory applications, such as adjustable transition temperatures, high degree of elastic elongations, and good mechanical strength. These materials are also potentially biodegradable and biocompatible, therefore suitable for biomedical and environmental applications.
... The first peak may be attributed to the decomposition of the PP matrix whereas the second peak which appeared at a higher temperature is due to the PP physicochemical attachment to the nanoparticle's surface. Similar results were reported by Guo et al. (45) and they claimed that this phenomenon is an indication of strong chemical bonding between the nanoparticles and the polymer matrix (45). ...
The modification of pristine nanoclay and its application in wood plastic composite (WPC) have been investigated in this paper. Pristine nanoclay was modified using transition metal ion (TMI) which was copper (II) chloride to achieve good dispersion and to improve properties of WPC. The morphology, composition, structure, and thermal stability of TMI-modified nanoclay were studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) analysis. The pristine (WPC/MMT) and TMI-modified (WPC/MMT Cu) nanoclay based WPC were made from polypropylene (PP), wood flour (WF), and maleic anhydride grafted polypropylene (MAPP) coupling agent. Pristine and modified nanoclay with different concentration (1 wt%, 2.5 wt%, 4 wt% and 5 wt%) were used as a reinforcing filler for WPC. Mechanical, physical, morphological, and thermal properties of the prepared composites were evaluated. Result exhibit that at 1 wt% nanoclay content, the tensile, flexural, and impact strength of WPC/MMT improved by approximately 6%, 4%, and 8%, respectively, compared to WPC without nanoclay. For the WPC/MMT Cu, the improvements in these properties were about 2.6, 2.1 and 3 times higher than the WPC/MMT. The physical and thermal properties also improved by incorporating modified nanoclay in WPC.
... Figure 5b shows a plot of derivative wt% of all the samples against temperature. Pure PCL has only one peak in the DTA curve, the intensity (peak height) of which decreases in the presence of the nanoparticles, PAni and RGO [29]. In the case of PCL-PAni/RGO composites, a small hump around 350°C is also observed in addition to the main peak. ...
Hybrid nanocomposites have the unique ability of enhancing material properties due to the existing synergistic effect of the fillers. Here we report such an eco-friendly hybrid nanocomposite comprising of polyaniline (PAni) and reduced graphene oxide (RGO) in polycaprolactone (PCL). The conducting PAni improved processability of PCL and the final composites were prepared by incorporating RGO reduced at 200 and 600°C temperatures to the PCL-PAni blend. PAni, PAni/RGO200 and PAni/RGO600 imparted good electrical conductivity to PCL and the fabricated flexible PCL-PAni/RGO nanocomposite exhibited good mechanical property, increased thermal stability and excellent electromagnetic interference shielding up to 42 dB at 13 GHz.
... Polymer nanocomposites are a special class of materials and have a wide range of potential applications [1,2] including sensors [3][4][5][6], membranes [7,8], solar cells [9], biomedical and biomimic materials [10,11], microwave absorption [12,13], electrochromic devices [14], electrocatalysts for fuel cells [15] and structural materials [16][17][18] arising from their unique physicochemical properties, which are superior to conventional composites with filler size larger than 100 nm. The properties and performances of these polymer nanocomposites can be tuned to satisfy the desired applications through varying the filler material, size, shape and loading level in the polymer matrix. ...
Conducting polymer-wide band gap semiconductor nanocomposites are prepared by polymerising pyrrole in presence of colloidal titanium dioxide sol. Characterisations of nanocomposites are carried out by Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction. Direct current and alternating current conductivities of nanocomposites have been investigated as a function of temperature and frequency for different concentrations of polypyrrole. Temperature dependence of ac conductivity suggests that small polaron tunnelling occurs in charge transfer process. A very large dielectric constant of about 13000 at room temperature has been observed. The interface between polypyrrole and TiO
... The iron oxide particles by ionic properties can be modified with functional polymer groups with COOH, NH 2 (Chibowski et al., 2009;Kandori et al., 2005;Li et al., 2004). The polymer coated particles can be synthesized by the ex situ method, i.e. dispersion of the nanoparticles in a polymeric solution, or in situ method, i.e. monomer polymerization in the presence of the synthesized nanoparticles (Mammeri et al., 2005;Guo et al., 2007). ...
