共查询到10条相似文献,搜索用时 125 毫秒
1.
Dillip K. Pradhan R. N. P. Choudhary B. K. Samantaray Awalendra K. Thakur R. S. Katiyar 《Ionics》2009,15(3):345-352
Polymer–clay nanocomposites consisting of polymer (polyethylene oxide) and NaI as salt with different concentration of organically
modified Na+-montmorillonite (DMMT) have been fabricated and characterized. X-ray diffraction analysis shows that the polymer–salt complexes
have been intercalated into the nanometric silicate layers of DMMT. Fourier transform infrared analysis shows that the polymer
structure in the clay interlayer is similar to that of the polymer–salt complexes, and there is a strong interaction between
the polymer–salt complexes and clay layers. A study of surface morphology using scanning electron microscopy reveals that
microstructure of composites is affected by clay addition. Complex impedance analysis was used to calculate the bulk resistance
of the composites. An enhancement in the conductivity of about one order of magnitude has been observed on 5% clay addition
compared to that of the polymer–salt complexes, and it decreases monotonically for higher clay concentration. The effect of
clay concentration on the structural and physical properties of polymer nanocomposites is well correlated. 相似文献
2.
We report the ac conductivity and relaxation behavior analysis for a heterogeneous polymer–clay nanocomposite (PNC) having
composition (polyacrylonitrile)8LiCF3SO3 + x wt.% dodecylamine modified montmorillonite. Charge transport behavior in an ionically conducting PNC has been analyzed systematically
and correlated with the macroscopic parameters like polymer glass transition temperature and available free mobile charge
carriers. Intercalation of cation coordinated polymer into the nanometric clay channels has been confirmed by high-resolution
transmission electron microscopy. The electrical properties of the intercalated PNC films have been studied using complex
impedance/admittance spectroscopy. Excellent correlation of relaxation behavior with polymer glass transition temperature
(T
g) confirmed the objectives of the work. An analysis of dielectric relaxation indicates that PNC films are lossy when compared
with polymer–salt film. This result is a direct outcome of faster ion dynamics leading to strong electrode polarization effect
due to the accumulation of charge carriers at the interface. 相似文献
3.
Synthesis,mechanical, and barrier properties of LDPE/graphene nanocomposites using vinyl triethoxysilane as a coupling agent 总被引:2,自引:0,他引:2
Jingchao Wang Chunhui Xu Huating Hu Li Wan Rong Chen Han Zheng Fangming Liu Min Zhang Xiaopeng Shang Xianbao Wang 《Journal of nanoparticle research》2011,13(2):869-878
Precise interface control and dispersal of graphene nanosheets in polymer hosts are challenging to develop high performance
graphene-based nanocomposites due to their strong interlayer cohesive energy and surface inertia. Here, we firstly report
an efficient and novel method to functionalize graphene nanosheets with vinyl triethoxysilane (VTES) and successfully blend
them with low density polyethylene (LDPE) to prepare nanocomposites. Fourier transforms infrared spectra (FTIR), Raman spectra,
and thermogravimetric analysis (TGA) proved that the graphene sheets were covalently bonded with VTES. The resulting nanocomposites
obtained the increases of up to 27.0 and 92.8% in the tensile strength and Young’s modulus, respectively, compared to neat
LDPE. The VTES–graphene not only remarkably improved the tensile strength of the composites, but also enhanced its toughness
by 17.7%. Oil permeability measurements showed that the absorption ratio of toluene by the LDPE/graphene composites decreased
from 56 to 39%, and its barrier properties have obviously been improved. This study opens a new route to optimize interface
structures and improve the comprehensive performances of graphene–polymer nanocomposites. 相似文献
4.
Inorganic-organic intercalation compounds comprised of montmorillonite (MMT) and aniline salts with different counter anions were prepared by a mechanochemical processing. The intercalation process and the formed structure of intercalation compounds were investigated via X-ray diffraction analysis. The amounts of intercalated species were very likely dependent on the types of counter anions and increased with decreasing the size of counter anions during the mechanochemical processing. Very interestingly, much larger interlayer expansions of 1.51 nm was observed for aniline hydrofluoride AnF- and aniline hydrochloride AnCl-MMT systems in higher intercalates loading levels, suggesting that neutral guest molecules also introduce within the interlayer regions together with anilinium cations by van der Waals interactions. Judging from the larger interlayer expansions and the size of guest molecules, intercalated species are expected to prefer a tri-molecular layer arrangement with their aromatic rings perpendicular to the silicate sheets. In contrast, for aniline hydrobromide AnBr-MMT, the interlayer expansion was ca. 0.52 nm, which reveals that only anilinium cations are introduced by ion exchange and they probably adopt a vertical orientation in the interlayers. It is inferred that aniline hydroiodide AnI-MMT compounds have a heterogeneous structure containing both anilinium and sodium cations in the interlayers. Different intercalation behaviors during the mechanochemical processing strongly suggest the smaller the size of counter anions, the more guest molecules can be intercalated into the confined clay interlayers in highly ordered arrangements. 相似文献
5.
So Yeon Bang Kyung Ju Lee Joo Hwan Koh Moon-Sung Kang Yong Soo Kang Jong Hak Kim 《Ionics》2008,14(2):143-148
In this paper, we aim to prepare polymer electrolytes consisting of NaI and I2 dissolved in poly(ethylene oxide) (PEO) and dioctyl phthalate (DOP) as an additive and apply the electrolytes to dye-sensitized
solar cells (DSSC). Upon the incorporation of salt, the phthalic-stretching C=O bands of DOP in Fourier transform infrared
spectra shifted to a lower wave number (Δf = 93 cm−1), confirming the unusual strong complex formation between sodium ions and phthalic oxygen. Coordinative interactions and
structural changes of PEO/NaI/I2/DOP electrolytes have also been characterized by wide angle X-ray scattering, presenting an almost amorphous structure of
the polymer electrolytes. The ionic conductivity of the polymer electrolytes reached ∼10–4 S/cm at room temperature at the mole ratio of [EO]:[Na]:[DOP] = 10:1:0.5, as determined by the four-probe method. DSSC using
the polymer electrolytes and conductive indium tin oxide glasses exhibited 2.9% of overall energy conversion efficiency (=P
max/P
in × 100) at one sun condition (100 mW/cm2). The good interfacial contact between the electrolytes and the dye-attached nanocrystalline TiO2 layers were verified by field-emission scanning electron microscopy. 相似文献
6.
S. M. Ashraf Sharif Ahmad Uffana Riaz 《Journal of Macromolecular Science: Physics》2013,52(6):1109-1123
Nanocomposites of montmorillonite (MMT) with poly(1‐naphthylamine) (PNA) is investigated for the first time by emulsion polymerization using three different oxidants. Polymerization of PNA was confirmed by Fourier transformation infrared (FT‐IR) as well as UV‐visible spectra. The in situ intercalative polymerization of PNA within MMT layers was confirmed by FT‐IR, X‐ray diffraction, conductivity; scanning electron microscopy (SEM) as well as transmission electron microscopy studies. X‐ray diffraction revealed intercalated as well as exfoliated structures of PNA/MMT nanocomposites, which were compared with the reported polyaniline‐MMT nanocomposites. It was found that the increase in the concentration of PNA in the interlayer galleries of MMT led to destruction of the layered clay structure resulting in exfoliation of the nanocomposite. Conductivity of the nanocomposites was found to be in the range of 10?3 to 10?2 S cm?1 which was found to be higher than the ones reported for polyaniline‐clay nanocomposites as well as PEOA‐OMMT nanocomposites at similar concentrations of intercalated species. The morphology of PNA/MMT nanocomposites was found to be governed by the nature of the oxidant used. 相似文献
7.
Hyo-Jin Nam Hongdoo Kim Soon Ho Chang Seong-Gu Kang Song-Ho Byeon 《Solid State Ionics》1999,120(1-4):189-195
Insertion of aniline molecules and subsequent polymerization using FeCl3 as an oxidizing agent were examined in the layers of rutile-type HNbMoO6. Although the polyaniline/host ratio was variable depending on the amount of intercalated aniline before polymerization, the interlayer spacing was constant as 6.3 Å regardless of the ratios. Comparison of FT-IR and FT-Raman spectra for (PANI)yNbMoO6 (0.26≤y≤0.64) clearly showed that both quinoid and benzenoid forms exist in the galleries of inorganic host. IR and Raman active modes of extracted PANI from the matrix were quite similar to those of emeraldine salt. 相似文献
8.
The successful growth of carbon filaments on two different precursors, i.e., the pristine sodium-montmorillonite (Na+MMT), which undergoes reflux at 100 °C (r-MMT), and the Na+MMT exchanged with Fe3+ ions (MMT(Fe)), was attained through chemical vapor deposition (CVD). The products obtained were characterized by X-ray diffraction, thermogravimetry, scanning electron microscopy, and transmission electron microscopy. Refluxing can make the Fe3+ ions in the octahedral layer of Na+MMT migrate to the interlayer and exchange with Na+ ions. Furthermore, through calcination at 500 °C, the Fe3+ ions migrate again to the surface of the clay layer and form iron oxides, which can serve as precursors for the deposition of carbon. Although r-MMT contained less iron than the MMT(Fe), the ultimate yield of carbon components grown was almost the same, indicating that the iron species in r-MMT possess higher catalytic activity. However, on the surface of r-MMT, CVD hardly generated carbon nanotubes with a clear hollow structure but that those with a carbon fiber structure instead. 相似文献
9.
The blend-based polymer electrolyte consisting of poly (vinyl chloride) (PVC) and poly (ethylene glycol) (PEG) as host polymers
and lithium perchlorate (LiClO4) as the complexing salt was studied. An attempt was made to investigate the effect of TiO2 concentration in the unplasticized PVC–PEG polymer electrolyte system. The XRD and FTIR studies confirm the formation of
a polymer–salt complex. The conductivity results indicate that the incorporation of ceramic filler up to a certain concentration
(15 wt.%) increases the ionic conductivity and upon further addition the conductivity decreases. The maximum ionic conductivity
0.012 × 10−4 S cm−1 is obtained for PVC–PEG–LiClO4–TiO2 (75–25–5–15) system. Thermal stability of the polymer electrolyte is ascertained from TG/DTA studies. 相似文献
10.
This paper describes the preparation and conductivity studies of polyindole–ZnO composite polymer electrolyte (CPE) with LiClO4. Polyindole–ZnO-based polymer nanocomposites were prepared by chemical method and characterized by XRD, infrared (IR), scanning
electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The IR spectrum confirms
the intermolecular interaction between polyindole and ZnO. The significant spectral changes of polyindole and ZnO nancomposites
reveal the strong interaction between polyindole and ZnO nanoparticles. The structural morphologies of the ZnO, polyindole,
and polyindole–ZnO are obtained from SEM. The TEM image of polyindole nanocomposite shows that ZnO is embedded in polyindole
matrix. An enhanced conductivity of 4.405 × 10−7 S cm−1 at 50 °C for the CPE was determined from impedance studies. 相似文献