Solution Intercalation Method Research Articles

Investigation on Electrical and Dielectric Behaviour of Halloysite Nanotube Incorporated Polycarbonate Nanocomposite Films

Polycarbonate (PC) nanocomposites were fabricated by solution intercalation method with halloysite nanotubes (HNTs) as reinforcement. The effects of HNT content on the structural and dielectric properties were investigated. The properties of the fabricated films were probed with the intention to establish the consequence of nano-fillers on electrical characteristics/behaviours with PC. The incorporation of HNT generates notable performance enhancements through reinforcement effect. The electrical conductivity of polycarbonate got better when more than 4 wt% HNT is added. Interestingly, the integration of HNT significantly increases the dielectric permittivity of composite films with low dielectric loss which makes the nanocomposites attractive in practical applications such as electrical devices, electrical packaging and capacitors. Furthermore, the structural aspects were elucidated by X-Ray diffraction studies, Fourier transform infrared spectroscopy and dispersion of nanofillers in PC matrix were evaluated by scanning electron microscopy.

Effects of Solvents on Structure, Morphology and Thermal Stability of Polystyrene-HNTs Nanocomposites by Ultrasound Assisted Solution Casting Method

Polymer-clay nanocomposites are extensively investigated as they are economical in comparison with other nanofillers and drastically enhances various physical and engineering properties of polymers. Among various clays used for polymer-nanocomposites, Halloysite nanotubes (HNTs) have gained tremendous attention as they have unique structure and properties. In the present work we have successfully synthesised polystyrene-HNT nanocomposites by ultrasound assisted solution intercalation method. In this method solvent plays a very crucial role in enhancing the overall properties of resultant nanocomposites as arrangement of filler in the polymer matrix depends upon how well the solvent is able to disperse filler which inturn enhances polymer properties. Hence in this work solvents toluene, benzene, chloroform, dichoromethane (DCM), tetrahydrofuran (THF) and carbontetrachloride (CCl4) were used for synthesis of nanocomposites and effect of these solvent on structure, morphology and thermal stability of nanocomposites was investigated. As per the characterization analysis, toluene was found to be the best solvent for synthesis of nanocomposites with enhanced properties and use of ultrasound aided in uniform distribution of clay in polymer matrix. Increase in basal spacing on sonication was revealed by x-ray diffraction (XRD) analyses. Scanning electron microscopy (SEM) results revealed uniform dispersion of filler inside the matrix on using acoustic cavitation as it promotes proportionate distribution of filler into the polymer matrix. Fourier transform and infrared (FT-IR) results confirmed encapsulation of HNTs into polymer. Differential scanning calorimetry (DSC) reports illustrated increase in glass transition temperature (Tg) on incorporating HNTs.

Poly(diallyldimethylammonium chloride)/clay nanocomposites: effect of molecular weight and concentration of polymer on the structural, thermal, and dielectric properties

Poly(diallyldimethylammonium chloride), PDADMAC, with low and high molecular weight and with concentrations 0.5, 1, and 2 times the cation exchange capacity (CEC) of the clay was used to modify sodium bentonite clay to prepare hybrid PDADMAC/clay nanocomposites using solution-intercalation method. The prepared hybrids were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Data analysis showed that PDADMAC/clay nanocomposites have intercalated structure. The results showed also that the nanocomposite prepared using high molecular weight PDADMAC with concentration one times the CEC of the clay has the most intercalated structure and the highest thermal stability between the prepared nanocomposites. The room temperature dielectric properties were studied as a function of frequency in which the values of real (e 1) and imaginary (e 2) parts of relative permittivity are calculated and discussed. Higher values of e 1 and e 2 are obtained using PDADMAC with high molecular weight. Increasing the concentration of polymer affects the values of e 1 and e 2 towards lower values.

Water-based polyamide imide – nanoclay coating: Preparation, characterization, thermal stability and visible transparency

Abstract In this study, water-based polyamide-imide (PAI)/clay nanocomposites were prepared using the solution intercalation technique. For this purpose, organo-montmorillonite (Cloisite 20A, C20A) was introduced into water-based polyamide-imide resin matrices. The water-based PAI (WBP)/Cloisite20A (C20A) nanocomposites film and the coating containing 1, 3 and 5 wt% of C20A were prepared using solution intercalation method by blending C20A and WBP solution. The morphology and structure of WBP/C20A nanostructured films containing 1, 3 and 5 wt% organoclay were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray Analysis (EDX). The distribution of C20A in WBP was revealed through XRD, FE-SEM and EDX-map. Furthermore, the thermal decomposition and optical transparency of WBP/C20A nanocomposites were examined. Thermogravimetric analysis and UV–vis spectroscopy indicated that the addition of C20A into the WBP matrix decreased the thermal decomposition temperatures and the optical transparency of the obtained nanocomposites, as compared to the pure WBP.

Evaluation of Nanostructure, optical absorption, and thermal behavior of poly(vinyl alcohol)/poly (N‐vinyl‐2‐pyrrolidone) based nanocomposite films containing coated SiO2 nanoparticles with citric acid and l(+)‐ascorbic acid

Nanocomposite films of poly(vinyl alcohol) (PVA)–poly(N‐vinyl‐2‐pyrrolidone) (PVP) blend filled with different weight percentages of nano‐silica were prepared using solution intercalation method. At first, to better dispersion and good compatibility of nano‐silica embedded in the polymer matrix, surface tailoring of it was carried out by two bio‐safe molecules, citric acid and l(+)‐ascorbic acid. Then, the effect of the modified nano‐silica (MS) on the PVA–PVP blend was studied. So, different characterization techniques were running including, Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction analysis (XRD), field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, and thermogravimetric analysis (TGA). POLYM. COMPOS., 39:2012–2018, 2018. © 2016 Society of Plastics Engineers

Grafting of poly[(methyl methacrylate)-block-styrene] onto cellulose via nitroxide-mediated polymerization, and its polymer/clay nanocomposite

For the first time, nitroxide-mediated polymerization (NMP) was used for synthesis of graft and block copolymers using cellulose (Cell) as a backbone, and polystyrene (PSt) and poly(methyl metacrylate) (PMMA) as the branches. For this purpose, Cell was acetylated by 2-bromoisobutyryl bromide (BrBiB), and then the bromine group was converted to 4-oxy-2,2,6,6-tetramethylpiperidin-1-oxyl group by a substitution nucleophilic reaction to afford a macroinitiator (Cell-TEMPOL). The macroinitiator obtained was subsequently used in controlled graft and block copolymerizations of St and MMA monomers to yield Cell-g-PSt and Cell-g-(PMMA-b-PSt). The chemical structures of all samples as representatives were characterized by FTIR and 1H NMR spectroscopies. In addition, Cell-g-(PMMA-b-PSt)/organophilic montmorillonite nanocomposite was prepared through a solution intercalation method. TEM was used to evaluate the morphological behavior of the polymer–clay system. It was demonstrated that the addition of small percent of organophilic montmorillonite (O-MMT; 3wt.%) was enough to improve the thermal stability of the nanocomposite.

The effect of monomer and clay proportion on the formation of polypyrrole clay intercalated nanocomposite

In this study, intercalated polypyrrole/montmorillonite nanocomposite was synthesized by a facile and simple solution intercalation method. The method is based on the exchanging of pyrrole monomers with sodium interlayer cations followed by polymerization by adding ammonium persulfate as oxidant. To avoid the spontaneous polymerization of pyrrole outside the clay, the proportions of pyrrole to clay and that of monomer to oxidant were varied. Several techniques have been used to study the structure and conductivity of the obtained materials: Fourier transform infrared spectroscopy, X-ray diffraction, Energy-dispersive X-ray spectroscopy analysis, scanning electron microscopy, Brunaner–Emmet–Teller technique, impedance spectroscopy and ultraviolet–visible spectroscopy. It was shown that it is not necessary to subject clay to organophilation with quaternary alkylammonium or to ultrasonic activation, or to treat it thermally to form intercalated nanocomposite. By increasing the amount of clay to that pyrrole, an intercalated polypyrrole clay nanocomposite is formed. Theevidence of the intercalation of polypyrrole is deduced from the X-ray diffraction and the Brunaner–Emmet–Teller technique specific surface. Both the expansion of the basal interlayer distance to 14 A and the decrease of the specific surface area from 78.2 for the clay to 48 m2 g–1 prove the formation of an intercalated structure. The conductivity has been measured using impedance spectroscopy. The dc conductivity was in the range of 2–10–3 S/cm.

Synergetic Effects of Graphene Oxide and Clay on the Microstructure and Properties of HIPS/Graphene Oxide/Clay Nanocomposites

ABSTRACTIn this paper, double-network structure nanocomposite with improved mechanical and thermal properties were prepared using high-impact polystyrene as a matrix phase, clay and graphene oxide as effective reinforcing fillers through a facile solution intercalation method. The structure and morphology of nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction analysis, and the synergetic effects of clay and graphene oxide on the final properties were investigated using tensile, dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) analysis. Mechanical analysis showed that the combination of graphene oxide and clay exerted a favorable synergistic effect on the tensile modulus and the yield strength of the ternary composite that are greatly improved as compared with neat high-impact polystyrene, high-impact polystyrene/graphene oxide, and high-impact polystyrene/clay binary composites due to the double-network structure formation between the nanofillers as confirmed by the direct morphological observations using transmission electron microscopy and scanning electron microscopy analysis. The viscoelastic behavior showed that storage modulus of ternary composite significantly improvement over than that of the pure matrix, high-impact polystyrene/graphene oxide and high-impact polystyrene/clay while network structure made. TGA and DMTA measurements also demonstrated that thermal stability of high-impact polystyrene matrix modified by graphene oxide and clay slightly enhanced during the creation of dual network structure of graphene oxide and clay. Our data suggest a potential application for the combination of graphene oxide and clay in graphene-based composite materials.

Pendant cyclic carbonate‐polymer/Na‐smectite nanocomposites via in situ intercalative polymerization and solution intercalation

Nanocomposites of sodium smectite with polyether- and polystyrene-containing pendant cyclic carbonates offer a novel approach to improving hydraulic barrier properties of Na-smectite liners to saline leachates. The cyclic carbonate polyethers were prepared by cationic ring opening polymerization of a cyclic carbonate-containing epoxide, whilst polystyrene polymers having pendant cyclic carbonate groups were obtained from radical photopolymerization of styrene. Na-smectite nanocomposites of these polymers were formed via clay in situ polymerization and solution intercalation methods. X-ray diffraction (XRD) and FT-IR analysis confirmed that the polyether can be intercalated within the layers of smectite via in situ as well as solution intercalation of the pre-formed polymer. The cyclic carbonate polyether nanocomposite was more resistant to leaching in 3M aqueous sodium chloride than its respective cyclic carbonate. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2421–2429

Preparation and Characterization of Surfactant-Modified Powder Activated Carbon (SM-PAC) Reinforced Poly (Ethylene Oxide) (PEO) Composites

Poly (ethylene oxide), PEO, which was used for a wide variety of applications is a flexible, crystalline, thermoplastic, water-soluble and non-ionic polymer. The most of studies on surfactant-modified activated carbon (SM-PAC) have been generally focused on the removal of contaminants. This study aims the preparation of PEO/(SM-PAC) composites, using solution-intercalation method. Firstly activated carbon was modified with cationic surfactant, Cetyltrimethylammonium Bromide (CTAB). Then PEO/(SM-PAC) composites were prepared using solution-intercalation method, with two different (SM-PAC) contents (1.0 and 2.0 wt.%). The characterization of the composites was made by X-ray diffraction (XRD), Fourier Infrared Spectroscopy (FT-IR), thermal analysis and tensile tests. The XRD patterns revealed that 2θ positions of the broad peaks belonging to the composites significantly shift to left compared with those of virgin PEO. The SEM images of the surfactant-modified powdered activated carbon (SM-PAC)/PEO composites prepared with the two different SM-PAC contents show that there is an intensive interaction between the CTA ions of modified activated carbon surface and the polymer chains. From the tensile tests, it was found that the unmodified powdered activated carbon dispersed into the polymer matrix made the ductile polymer more brittle. However, the tensile and yield strengths of the composite, prepared with modified powdered activated carbon, have decreased, and the strain percent value has significantly increased.

Poly(ethylene oxide)/clay nanaocomposites: Thermal and mechanical properties

Poly(ethylene oxide) (PEO)/clay nanocomposites were prepared by a solution intercalation method using chloroform as a solvent. The nanocomposites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and also investigation of some mechanical properties of the composites. Formation of nanocomposite was confirmed by XRD analysis. The increasing tendency of exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. An increase in PEO crystallinity in case of nanocomposite, was confirmed by an increase in the heat of melting as indicated by DSC. Improvement in tensile properties in all respect was observed for nanocomposites with clay content.

Dimensionally stable and light-colored polyimide hybrid reinforced with layered silicate

Light-colored polyimide hybrids with a quaternary alkylammonium modified montmorillonite, Cloisite® 20A (C20A) were successfully synthesized via a solution intercalation method. The structural and morphological features of the PI/C20A hybrids were characterized by Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD), field emission scanning electron microscopy (FE-SEM), and spherical aberration correction scanning transmission electron microscope (STEM). The dimensional stabilities were strongly dependent upon the chemical and morphological structures which were influenced by the Cloisite® 20A loading content. A critical Cloisite® 20A concentration was obtained for the evolution of both the structural and physical properties of the PI/C20A hybrids. The dynamic stress behaviors were investigated in situ by using the wafer bending method during thermal imidization of the softbaked PI/C20A hybrid precursor and thermally cured hybrid films using a thin film stress analyzer. The PI/C20A hybrid films exhibited stability at 510 °C, high glass transition and relatively low coefficient of thermal expansion, and an improved solvent resistance capacity. Open image in new window

Amelioration of anticorrosion and hydrophobic properties of epoxy/PDMS composite coatings containing nano ZnO particles

Epoxy-polydimethylsiloxane (PDMS) nanocomposite coatings loaded with different concentrations (ranged from 2 to 8% (w/w)) of ZnO nanoparticles have been successfully achieved by using the solution intercalation method. In this study, it has been aimed to investigate corrosion protection performance and hydrophobic properties of epoxy/PDMS nanocomposites (NC). Fourier transform infrared (FTIR) spectroscopy was utilized in order to study the chemical structure of the developed coatings. The coating surface wettability was studied by contact angle measurements and the dispersion of ZnO nanoparticles was examined via field emission scanning electron microscope (FESEM). The effects of ZnO nanoparticles on the corrosion resistance and the barrier performance were investigated by electrochemical impedance spectroscopy (EIS). Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) From the FTIR spectra it was observed that the incorporation of nano ZnO particles has demonstrated peak shift and change in intensity. The incorporation of nano ZnO particles within the hybrid polymeric matrix had improved the hydrophobicity in terms of contact angle which reached maximum as 128° for NC6 system. NC2 coating had shown higher coating resistance more than 109 Ω even after 30 days of exposure in electrolyte medium. The results obtained from TGA and DSC studies demonstrated that introducing PDMS to epoxy resin increased Tg whereas the incorporation of ZnO nanoparticles in the nanocomposite coatings showed reduction in degradation temperature, cross-linking density of the composite by lowering Tg.

POLYVINYL ALCOHOL/SILICA/CLAY COMPOSITES: EFFECT OF CLAY ON SURFACE MORPHOLOGY AND THERMO-MECHANICAL PROPERTIES

A simplified route towards the synthesis of polyvinyl alcohol/silica/clay (PVA-SiO2-clay) composites was presented. PVA-SiO2-clay composites were prepared via solution intercalation method. All the composites were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), adsorption isotherm (BET), X-ray fluorescence (XRF), tensile test and Thermogravimetric Analysis (TGA). FTIR spectrum indicated that PVA-SiO2-clay composites especially clay (1.28E) loaded composites had much less transmittance percentage compared to pure PVA and others clay composites. The SEM revealed that the interfacial bonding between PVA-SiO2 and clay (1.28E) was much better than others clay loaded composites which was reflected in adsorption isotherm. The BET result also showed high specific surface area with low diameter of pore size of the composites. The thermal stability of PVA-SiO2-clay (1.28E) composites was the highest and it had higher activation energy due to the strong bonding between the trimethyl stearyl ammonium with both PVA-SiO2. The XRF result showed that clay (1.28E) loaded composites contained significant high percentage of Si which confirmed the presence of Si-O-Si stretching vibration while the high percentage of K proved the clay mineral content in the composite. Clay (1.28E) enhanced the tensile strength and modulus of PVA-SiO2-clay composites among all the composites.

Synthesis, mechanical properties and thermal stability of the functional reduced graphene oxide/bisphenol A cyanate ester nanocomposites

In this paper, a novel functional reduced graphene oxide (F-RGO) material was synthesized via the reduced graphene oxide graft with a silane coupling agent. Then, the functional reduced graphene oxide/bisphenol A cyanate ester (F-RGO/CE) nanocomposites were prepared with a solution intercalation method. The results showed that the F-RGO played a role of catalyst at the curing process of the F-RGO/CE nanocomposites. The optimal F-RGO nanosheets (3 wt%) improved the mechanical properties and the maximum values of the mechanical properties were impact strength 15.334 kJ/m2, flexural strength 104.68 MPa, tensile strength 9.3 MPa, modulus 2041.6 MPa and the elongation break values 5.5 mm for the F-RGO/CE nanocomposites, respectively. The Tg, Tc, crystallinity and densities of the F-RGO/CE nanocomposites were slightly decreased compared with the pure CE resin, respectively. And the addition of F-RGO slightly increased the thermal properties of the pure CE resin.

Ammonium alcohol polyvinyl phosphate intercalated LDHs/epoxy nanocomposites

To improve the flame retardancy and mechanical properties of epoxy (EP), a novel intercalated layered double hydroxides (ILDHs) were synthesized by a solution intercalation method using ammonium alcohol polyvinyl phosphate as intercalator. The ILDHs were examined by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), energy-dispersive spectrometry and scanning electron microscopy (SEM). The conditions for synthesis of ILDHs have been optimized. Thermogravimetric analysis indicated a good char-forming property of ILDHs. The flame retardancy of epoxy was improved by adding ILDHs. The EP composites containing 30–40 mass% ILDHs passed UL-94V-0 rating. Tensile strength was also enhanced by adding 30–40 mass% ILDHs, which was attributed to the involvement of physical cross-linking network among layered particles and polymer chains. The morphology and structures of residues generated during LOI test were investigated by SEM and FTIR to support a fundamental analysis for the mechanism of char formation. SEM observations of residues of the ILDHs/EP confirmed the formation of an incompact charred layer during combustion, which could inhibit the transmission of heat and mass during combustion. It may be inferred that ILDHs acted as a catalyst for esterification, dehydration and compact char formation of EP system.

Effect of graphene oxide on the physical, mechanical and thermo-mechanical properties of neoprene and chlorosulfonated polyethylene vulcanizates

The present research work demonstrated the effect of graphene oxide (GO) on the physical, mechanical, thermo-mechanical etc., properties of neoprene (CR) and chlorosulfonated polyethylene (CSPE) vulcanizates. CR and CSPE based nanocomposites were prepared by both solution intercalation and melt intercalation methods. The changes obtained in the morphology, cure characteristics, mechanical, thermal, thermo-mechanical properties of the rubber nanocomposites have been widely investigated. X-ray diffraction analysis (XRD) and transmission electron microscopic (TEM) analysis of the samples revealed partial exfoliated structure of GO containing rubber composites. Mechanical, thermal, cure and thermo-mechanical properties of the elastomeric nanocomposites were improved compared to the neat rubbers.

Using Mg‐Al‐layered double hydroxide intercalated with chiral dicarboxylic acid for the reinforcement of isoleucine amino acid containing poly(amide‐imide)

A series of bionanocomposite (BNC) materials based on isoleucine containing poly(amide‐imide) (PAI) and modified MgAl‐layered double hydroxide (LDH) were prepared by solution intercalation method for the first time. An optically active PAI was synthesized by direct polycondensation reaction of N,N'‐(pyromellitoyl)‐bis‐isoleucine with 3,5‐diamino‐N‐(thiazol‐2‐yl)benzamide under green conditions. Organically modified LDH was prepared via ion exchange reaction of MgAl‐LDH in a solution of N,N'‐(pyromellitoyl)‐bis‐l‐isoleucine in distilled water. X‐ray diffraction (XRD) results of modified LDH show an increase in interlayer distance as compared to the unmodified one. The obtained polymer and modified LDH were used to prepare chiral and high‐performance hybrid materials. Fourier transform infrared spectroscopy, XRD, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis (TGA) techniques were used to study the morphology and thermal properties of the obtained hybrid materials. TGA data indicated an increase in thermal stability of the BNCs as compared to the pure polymer. POLYM. COMPOS., 37:3288–3295, 2016. © 2015 Society of Plastics Engineers

Composite polymer electrolyte membranes based on Mg–Al layered double hydroxide (LDH) platelets for H2/air-fed fuel cells

Layered double hydroxides (LDH) were incorporated into Nafion polymer for the development of innovative hybrid nanocomposites exploitable in the high temperature PEM fuel cells. Mg2+/Al3+ LDHs (at two metal ratios, 2:1 and 3:1) with different countervailing anions in the interlayer space (CO32−, ClO4−, NO3−) were synthesized, while fully exfoliated composite membranes were prepared by solution intercalation method. NMR technique (diffusion and relaxation) was used to investigate the transport properties of water confined in membranes. The protons dynamics appears to be influenced from the Mg2+/Al3+ metal ratios of the nanoadditives, while the type of anion affects the electrochemical measurements. Compared to filler-free Nafion, both water absorption and diffusion in the hybrid membranes are increased with a noteworthy behavior at high temperature, proving the exceptional water retention property of these materials together with superior mechanical properties. The proton conductivity reaches 2.7×10−2Scm−1 at 100°C and 50% RH, as the best value for the composite based on Naf-LDH-Mg2+/Al3+(2/1)-NO3−.

ZnO–montmorillonite as Photocatalyst and Flocculant for Inhibition of Cyanobacterial Bloom

The cyanobacterial bloom in water has adversely affected water quality, local economies, and human health. Therefore, the removal and restricting the growth of harmful algae are of particular interest. In this study, ZnO–montmorillonite that could flocculate and restrict the growth of Microcystis aeruginosa, used as a probe of cyanobacterial, was prepared by hydrothermal solution intercalation method and characterized by means of XRD, IR, and TEM. In ZnO–montmorillonite, ZnO nanoparticles were either embedded in the interlayer space of montmorillonite or dispersed on montmorillonite surface. The determinations of chlorophyll a levels, total soluble protein content, and malondialdehyde concentration demonstrated that ZnO–montmorillonite had stronger flocculation effect on M. aeruginosa compared with natural montmorillonite and ZnO under visible light and had a better photocatalytic degradation effect on M. aeruginosa than ZnO under UV irradiation after 1 h. Under UV, 95 % removal efficiency was achieved for M. aeruginosa in 1 h using 50 mg L−1 ZnO–montmorillonite, and the proliferation of M. aeruginosa was totally inhibited due to the high photocatalytic activity and absorption flocculation ability of ZnO–montmorillonite. Furthermore, the cell structure was irreversibly damaged and the cell lysed. The synergy of absorption flocculation and photocatalysis of ZnO–montmorillonite promoted the removal of M. aeruginosa.