ENGINEERING THE MICROSTRUCTURE AND OPTICAL FEATURES OF SiC- MWCNTS NANOPARTICLES DOPED PVA-PAA FOR PROMISING INDUSTRIAL APPLICATIONS

Here, we demonstrate an easy method for the preparation of highly electrically conductive polycarbonate (PC)/multiwalled carbon nanotubes (MWCNTs) nanocomposites in the presence of poly(butylene terephthalate) (PBT). In the presence of MWCNTs, PC and PBT formed a miscible blend, and the MWCNTs in the PC matrix were uniformly and homogeneously dispersed after the melt mixing of the PC and PBT–MWCNT mixture. Finally, when the proportion of the PC and PBT–MWCNT mixture in the blend/MWCNT nanocomposites was changed, an electrical conductivity of 6.87 × 10−7 S/cm was obtained in the PC/PBT–MWCNT nanocomposites at an MWCNT loading as low as about 0.35 wt %. Transmission electron microscopy revealed a regular and homogeneous dispersion and distribution of the MWCNTs and formed a continuous conductive network pathway of MWCNTs throughout the matrix phase. The storage modulus and thermal stability of the PC were also enhanced by the presence of a small amount of MWCNTs in the nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

This investigation deals with an easy method to develop electrical conductivity in polycarbonate (PC)/multi-wall carbon nanotube (MWCNT) nanocomposites with low loading of MWCNT. This was achieved by melt-blending of in-situ bulk polymerized low molecular weight poly(methyl methacrylate) (PMMA)/MWCNT nanocomposites and PC in various compositions at 280 degrees C in internal mixer. Differential scanning calorimetry (DSC) study showed single Tg in (85/15 w/w) PC/PMMA blend, indicating miscibility of PC and PMMA in the blend. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies of the melt-blended PC/PMMA/MWCNT nanocomposites revealed homogeneous dispersion and distribution of MWCNTs in PC matrix. Finally, through optimizing the blending composition of PC and PMMA/MWCNT nanocomposites, electrical conductivity of 3.74 x 10(-7) S x cm(-1) was achieved in the (85/15 w/w) PC/PMMA/MWCNT nanocomposites with the MWCNTs loading as low as approximately 0.37 wt%. Storage modulus of PC was found to increase significantly in presence of small amount (0.37 wt%) of MWCNTs in the nanocomposites.

This work aims to fabricate the undoped and doped polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)-blended polymers with ZnCo2O4-CdS, multi-walled carbon nanotubes (MWCNTs), and polyaniline (PANI) to utilize them in many optoelectronics and energy storage fields. The structure of the dopant and the blended polymers has been investigated. The sample with 0.25 wt% PANI has the greatest absorption. The lowest direct and indirect energy gap values are 5.59 eV and 4.96 eV, respectively, accomplished with a PANI concentration of 0.25 wt %. The optical dielectric constant, optical conductivity, and energy loss functions of the samples improved. Compared to the unfilled sample, the fluorescence intensities of the filled samples are lowered. The filled blended polymer including ZnCo2O4, CdS, MWCNTs, and 0.2 wt % PANI exhibited the greatest dielectric constant (ε′, 26.67 at 1 kHz) compared to the other polymers (12.47–19.48 at 1 kHz). Loaded PVA/CMC composite polymer with ZnCo2O4, CdS, MWCNTs, and 0.15 wt % PANI displayed the greatest energy density values (0.01091 J/m3 @ 1 kHz). The Nyquist plots (Z’ against Z”: real against imaginary parts of the electric impedance) for all blended polymers suggested that the insertion of fillers affected the ionic conductivity of the different blended polymers.

Synthesis characterization, optical and electrical properties of polyvinyl alcohol/multi-walled carbon nanotube nanocomposites: A composition dependence study

ABSTRACTPolyvinylpyrrolidone/hydroxyl-functionalized multiwalled carbon nanotube and sulfonyl-functionalized multiwalled carbon nanotube nanocomposites were prepared in aqueous media. The structure, morphology, and thermal characterization of the prepared nanocomposites were done by Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry techniques. The polyvinylpyrrolidone/hydroxyl-functionalized multiwalled carbon nanotube and polyvinylpyrrolidone/sulfonyl-functionalized multiwalled carbon nanotube nanocomposites improved the thermal properties of polyvinylpyrrolidone. According to the differential scanning calorimetry analysis, the glass transition temperature of 101.6 and 84.6°C is observed for the polyvinylpyrrolidone/hydroxyl-functionalized multiwalled carbon nanotube (5% w/w) and polyvinylpyrrolidone/sulfonyl-functionalized multiwalled carbon nanotube (5% w/w) nanocomposites, respectively. The energy-dispersive X-ray spectroscopy image of polyvinylpyrrolidone/sulfonyl-functionalized multiwalled carbon nanotube (5% w/w) nanocomposite showed a homogenous distribution of sulfonyl-functionalized multiwalled carbon nanotube in the polyvinylpyrrolidone matrix.

Polymer Nano composites and lithium polymer electrolytes are always scientifically speaking. It is formed by dissolving Multiwalled carbon nanotubes(MWNT) and lithium salt in poly(ethylene glycol), poly(vinyl alcohol) blends with the aim of developing new types of polymer composite characterized by enhanced thermal stability, as well as by improved electrical properties. The interaction of the MWNT and LiNO3 with the polymer blend were confirmed by a Fourier transform infrared (FTIR) spectroscopy study. The thermal properties of the polymer blend with the MWNT were carried out by means of differential scanning calorimetry (DSC). It is evident from DSC that the polymer/MWNT had a decreased of Tm and heat crystalline fusion(∆Hc) with of increased MWNT. Scanning electron microscopy is used to study the dispersion of the MWNT and LiNO3 in the polymer blend. Electrical conductivity was observed for PVA/PEG/MWNT containing 0.40 wt % MWNT was 7.98 X10-7S/cm where the PVA/PEG was 8.31 X10-8S/cm also electrical conductivity of PVA/PEG/LiNO3 containing 40wt % was 1.02 X10-7S/cm. Relative changes in the conductivity of blends with different concentrations and temperatures are analyzed.

Facile synthesis of MoS3/carbon nanotube nanocomposite with high catalytic activity toward hydrogen evolution reaction

The preparation, characterization, and properties of poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWCNTs) nanocomposites are described. Nanocomposites have been prepared by melt-blending in a batch mixer. Both unmodified and surface modified MWCNTs have been used for the nanocomposites preparation. Using both unmodified and modified MWCNTs, the effect of surface modification in nanocomposites is investigated by focusing on three major aspects: dispersion characteristics, mechanical properties, and electrical conductivity measurements. Dispersion of the MWCNTs in the PMMA matrix is examined by scanning and transmission electron microscopy that revealed a homogeneous distribution-dispersion of MWCNTs in the PMMA matrix for both unmodified and modified MWCNTs. Thermomechanical behavior is studied by dynamic mechanical analyzer and results showed a substantial improvement in the mechanical properties of PMMA in conjunction to an increase in the elastic behavior. The tensile properties of neat PMMA moderately improved after nanocomposites preparation with both modified and unmodified MWCNTs, however, electrical conductivity of neat PMMA significantly improved after nanocomposites preparation with 2 wt% unmodified MWCNTs. For example, the through plane conductivity increased from 3.6 x 10(-12) S x cm(-1) for neat PMMA to 3.6 x 10(-9) S x cm(-1) for nanocomposite. The various property measurements have been conducted and results have shown that, in overall, surface modifications have very little or no effect on final properties of neat PMMA.

The most common approaches for the fabrication of poly(vinylidene fluoride)(PVDF)/ multi-walled carbon nanotubes(MWNTs) nanocomposites involve solution crystallization and melting crystallization methods. In this study, PVDF/ MWNTs nanocomposites with varied contents of MWCNTs (up to 0.3wt.%) were prepared via solution crystallized at 80 °C, solution crystallized at 120 °C and melting at 200 °C. The effect of processing conditions on the crystal structure, morphology, dielectric and ferroelectric properties of PVDF with the presence of MWNTs was investigated. It is seen that crystallization temperatures and the concentrations of MWNTs have a synergetic effect of on the crystal phase and crystallinity of PVDF. Higher crystallization temperatures appeared to be detrimental to the dispersion of MWNTs in PVDF matrix, however, it was advantage to the growth of crystals and leaded to a higher degree of crystallinity. Lower crystallization temperatures favored the dispersion of MWNTs in PVDF matrix, which can effectively promote the formation of polar crystalline β-phase of PVDF. In addition, MWNTs at relatively low content (<0.1 wt.%) can disperse well in PVDF matrix in different approaches, resulting in high content of -phase and enhancements in dielectric and ferroelectric properties.

This study focuses on the electrical properties of polycarbonate (PC)/poly(ε-caprolactone) (PCL)-multiwall carbon nanotube (MWCNT) nanocomposites. MWCNTs were incorporated into thermoplastic PC matrix by simple melt blending using biodegradable PCL based concentrates with MWCNT loadings (3.5 wt%). Because of the lower interfacial energy between MWCNT and PCL, the nanotubes remain in their excellent dispersion state into matrix polymer. Thus, electrical percolation in PC/PCL-MWCNT nanocomposites was obtained at lower MWCNT loading rather than direct incorporation of MWCNT into PC matrix. AC and DC electrical conductivity of miscible PC/PCL-MWCNT nanocomposites were studied in a broad frequency range, 101−106 Hz and resulted in low percolation threshold (pc) of 0.14 wt%, and the critical exponent (t) of 2.09 from the scaling law equation. The plot of logσDC versus p−1/3 showed linear variation and indicated the existence of tunneling conduction among MWCNTs. At low MWCNT loading, the influence of large polymeric gaps between conducting clusters is the reason for the frequency dependent electrical conductivity. Transmission electron microscopy and field emission scanning electron microscopy showed that MWCNTs were homogeneously dispersed and developed a continuous interconnected network path throughout the matrix phase and miscibility behavior of the polymer blend. POLYM. ENG. SCI., 54:646–659, 2014. © 2013 Society of Plastics Engineers

This paper describes, a new, sensitive, and low-cost solid-phase extraction method using poly (N-phenylethanolamine)/multiwalled carbon nanotube (MWCNT) nanocomposite for extraction, preconcentration, and flame atomic absorption spectrometric determination of lead in food and water samples at trace levels. The poly (N-phenylethanolamine)/MWCNT nanocomposites were characterized by Fourier transformed infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) surface area (SBET), and scanning electron microscopy (SEM). Factors affecting the preconcentration of lead such as the pH of samples, flow rates, type and volume of eluent, and the effect of interfering ions and breakthrough volume on the separation and determination of lead ions were investigated. The optimum conditions for the adsorption step were 5.0 and 18 mL min−1 for pH and sample flow rate, respectively, and for desorption step, the optimal condition were 1.5 mL, 1 mol L−1 HCl, and 2 mL min−1, for volume of eluent, concentration of eluent, and eluent flow rate, respectively. The maximum sorbent capacity of the poly (N-phenylethanolamine)/MWCNT nanocomposite was calculated to be 152.1 mg g−1. The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 100, 3.1 % (10.0 μg L−1, n = 5), and 0.8 μg L−1, respectively. The presented method was validated by certified reference material (NIST SRM 1515 Apple leaves and IAEA-336 Lichen) and finally applied to analysis of lead ions in food (Citrus limetta, kiwi, pomegranate, and fish samples) samples. The obtained data for analysis of lead ions in food samples were in the concentration range of 4.1–50.8 μg kg−1.

A drug delivery system (DDS) was prepared with a temperature and pH-responsive hydrogel. Poly(vinyl alcohol) (PVA)/poly(acrylic acid) (PAAc)/poly(N-isopropylacrylamide) (PNIPAAm)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by radical polymerization for the temperature and pH-responsive hydrogels. MWCNTs were employed to improve both the thermal conductivity and mechanical properties of the PVA/PAAc/PNIPAAm/MWCNT nanocomposite hydrogels. Various amounts of MWCNTs (0, 0.5, 1 and 3 wt%) were added to the nanocomposite hydrogels. PVA/PAAc/PNIPAAm/MWCNT nanocomposite hydrogels were characterized with a scanning electron microscope. The mechanical properties were measured with a universal testing machine. Swelling and releasing properties of nanocomposite hydrogels were investigated at various temperatures and pHs. Temperature and pH-responsive release behavior was found to be dependent on the content of MWCNTs in nanocomposite hydrogels.

Electro-responsive transdermal drug delivery behavior of PVA/PAA/MWCNT nanofibers

Ni3S2/carbon nanotube nanocomposite as electrode material for hydrogen evolution reaction in alkaline electrolyte and enzyme-free glucose detection

Evaluating the microwave absorbing performance of polymer-free thin Fe3O4−MWCNT NCs in X-band region