Effect of nanoclay type on dyeability of polyethylene terephthalate/clay nanocomposites

Polyethylene terephthalate (PET)-based nanocomposites containing three differently modified clays were prepared by melt compounding. The influence of type of clay on disperseability, thermal, and dyeing properties of the resultant nanocomposite was investigated by various analytic techniques, namely, X-ray diffraction, optical microscopy (OPM), differential scanning calorimetry, thermal gravimetric analysis, dynamical mechanical thermal analysis, contact angle measurement (CAM), reflectance spectroscopy, and light fastness. OPM images illustrated formation of large-sized spherulites in pure PET, while only small-sized crystals appeared in PET/clay nanocomposites. Decreased glass transition temperatures for all PET/clay nanocomposites indicate that the amorphous regions of such composites become mobile at lower temperatures than those in pure PET. CAMs on the resultant PET composites demonstrated that the wettability of such composites depends on hydrophilicity of the nanoclay particles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal and Morphological Properties of Organo Modified Nanoclay/Polyethylene Terephthalate Composites

The purpose of this study is polyethylene terephthalate (PET) and modified organo-nanoclay with different masses and to contribute to the different areas of use and literature by examining these nanocomposites physical, chemical and thermal features. In this study, nanocomposite films, which work in PET that is a type of polymeric material, and work into modified organo-nanoclays with different percentages, obtained with the method called as in situ polymerization. The chemical structures of nanocomposites prepared were investigated by fourier transform infrared spectroscopy. The surface morphologies of this nanocomposites were examined by scanning electron microscope. Their thermal properties were analyzed by differential scanning calorimetry and thermogravimetric analysis. According to the results obtained, the thermal stabilities of modified nanoclay composites got better than PET. Besides, while the percent of clay in the doped PET was rising, its fragility increased. At the same time, high mass of clay formed when the percent of contribution developed. Thus, the surface interaction of polymer–clay decreased, because the composed aggregations prevented the polymer matrix from going into the layer of clay.     

Harmless hydrogels based on PVA/Na+‐MMT nanocomposites for biomedical applications: Fabrication and characterization

A series of nanocomposite hydrogels were prepared by a freeze‐thaw process, using polyvinyl alcohol (PVA) as polymer matrix and 0–10 wt% of hydrophilic natural Na‐montmorillonite (Na⁺‐MMT), free from any modification, as composite aggregates. The effect of nanoclay content and the sonication process on the nanocomposite microstructure and morphology as well as its properties (physical, mechanical, and thermal) were investigated. The microstructure and morphology were investigated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and X‐ray diffraction technique. The thermal stability and mechanical properties of nanocomposite hydrogels were examined using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis; moreover hardness and water vapor transmission rate measurements. It was concluded that the microstructure, morphology, physical (thermal) and mechanical properties of nanocomposite hydrogels have been modified followed by addition of nanoclay aggregates. The results showed that Na⁺‐MMT may act as a co‐crosslinker. Based on the results obtained, the nanocomposite hydrogel PVA/Na⁺‐MMT synthesized by a freeze‐thaw process, appeared to be a good candidate for biomedical applications. POLYM. COMPOS., 38:1135–1143, 2017. © 2015 Society of Plastics Engineers     

Improved thermal properties of jute fiber‐reinforced polyethylene nanocomposites

The thermal behavior of chemically modified jute fiber‐reinforced polyethylene (PE) nanocomposites was investigated. Nanocomposites were prepared by hot press molding technique using different fiber loadings (5, 10, 15, and 20 wt%) for both treated and untreated fibers. Jute fibers were chemically modified with benzene diazonium salt to increase their compatibility with the PE matrix. Surface and thermal properties were subsequently characterized. Fourier transform infrared spectroscopy and scanning electron microscopy analysis were used to study the surface morphology. Thermogravimetric analysis (TGA) and differential scanning calorimetry were carried out for thermal characterization. Fourier transform infrared spectroscopy and scanning electron microscopy study showed interfacial interaction among jute fiber, PE, and nanoclay. It was observed that, at optimum fiber content (15 wt%), treated jute fiber‐reinforced composites showed better thermal properties compared with that of untreated ones and also that nanoclay‐incorporated composites showed enhanced higher thermal properties compared with those without nanoclay. POLYM. COMPOS., 38:1266–1272, 2017. © 2015 Society of Plastics Engineers     

Characterization and electrical conductivity of poly(ethylene glycol)/polyacrylonitrile/multiwalled carbon nanotube composites

Poly(Lactic acid) (PLA)‐layered silicate nanocomposite films were prepared by solvent casting method. The films were irradiated with Co⁶⁰ radiation facility at dose of 30 kGy. The effect of γ irradiation on mechanical properties of the neat PLA and nanocomposites was evaluated by data obtained from tensile testing measurements. The tensile strength of the irradiated PLA films increased with addition of 1 wt % triallyl cyanurate indicating crosslink formation. Significant ductile behavior was observed in the PLA nanocomposites containing 4 pph of nanoclay. Incorporation of nanoclay particles in the PLA matrix stimulated crystal growth as it was studied by differential scanning calorimetry. The morphology of the nanocomposites characterized by transmission electron microscopy and X‐ray diffraction revealed an exfoliated morphology in the PLA nanocomposite films containing 4 pph of nanoclay. Only very small changes were observed in the chemical structure of the irradiated samples as it was investigated by Fourier transform infrared spectroscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Antimicrobial resistance of clay polymer nanocomposites

Antimicrobial-resistant polymeric Na⁺–bentonite nanocomposites were prepared by treating Na⁺–bentonite (Na⁺–Bent) with polymeric ultra-thin films of poly(diallyldimethyl ammonium chloride) (PDADMAC), poly(methylmethacrylate) (PMMA) and poly(vinylidene chloride) (PVDC) by admicellar polymerization technique. The clay polymer nanocomposites (CPNs) were characterized by several techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), BET surface analysis, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). In additional, the antimicrobial resistance was studied by measuring the diameter of inhibition zone of growths of Escherichia coli and Salmonella typhimurium. The results showed an inhibitory effect of these CPN against microbial growth in inoculated samples. The CPN exhibited efficacy in the inhibition of bacterial growth.     

Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites in comparison to the polyurethane‐free films have been proven. POLYM. COMPOS., 38:1167–1174, 2017. © 2015 Society of Plastics Engineers     

Bottle‐to‐bottle recycling of PET via nanostructure formation by melt intercalation in twin screw compounder: Improved thermal,barrier, and microbiological properties

Attempts have been made to modify the properties of the injection processing‐scraped PET (denoted as RPET) via intercalation with different levels of organically modified nanoclay (montmorillonite) by melt blending in a corotating twin screw compounder. The clay platelets dispersion state has been qualitatively correlated with the melt linear viscoelastic as well as tensile and barrier properties of the prepared nanocomposites. Oxygen permeation of the nanocomposite PET films showed significant reduction compared with the pristine PET polymer. All the PET/nanoclay composites exhibited no bacterial growth, with no potentiality to generate acetaldehyde, as measured by GC/Mass analyzer. X‐ray diffractometry and transmission electron microscopy performed on the scraped PET/organoclay nanocomposite samples showed increase in d₀₀₁ spacing of the clay layers and their dispersion throughout the PET matrix. Differential scanning calorimetry analysis showed higher crystallization temperature as well as crystallization enthalpy (ΔH_c) for the nanocomposite samples, compared with the unprocessed virgin PET. The RPET nanocomposite samples composed of 3 and 5% of nanoclay exhibited enhanced melt elastic modulus and pseudosolid‐like behavior at low shear frequencies measured by rheomechanical spectroscopy than the unfilled pristine‐scraped PET, indicating the formation of nanoscopic network structure by the clay platelets, which leads to the development of nanostructured resin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of hydrogen bonding on the rheology of polycarbonate/organoclay nanocomposites

The linear dynamic viscoelastic properties and non-linear transient rheology of polycarbonate (PC)/clay nanocomposites were investigated at temperatures ranging from 240 to 280 °C. For the study, nanocomposites of PC and natural montmorillonite (Cloisite Na⁺) or chemically modified clay (Cloisite 30B) were prepared by melt blending in a twin-screw extruder. Cloisite 30B is a natural montmorillonite modified with methyl, tallow, bis-2-hydroxyethyl, quaternary ammonium chloride (MT2EtOH). In both PC/Cloisite Na⁺ and PC/Cloisite 30B nanocomposites the concentration of clay was varied from 2.3 to 4.3 wt%. In situ Fourier transform infrared (FTIR) spectroscopy results show that at temperatures ranging from 30 to 280 °C the carbonyl groups in PC and the hydroxyl groups in MT2EtOH of Cloisite 30B in PC/Cloisite 30B nanocomposites formed hydrogen bonds, while no evidence of hydrogen bonding was observed in the PC/Cloisite Na⁺ nanocomposites. There are no discernible sharp reflections in the X-ray diffraction (XRD) patterns of PC/Cloisite 30B nanocomposites, after Cloisite 30B having the d₀₀₁ spacing of 1.85 nm was mixed with PC, whereas the d₀₀₁ spacing changes little (1.17 nm) before and after the mixing of Cloisite Na⁺ to PC. Transmission electron microcopy (TEM) images show that organoclay platelets are well dispersed in PC/Cloisite 30B nanocomposites, while the untreated clay platelets are poorly dispersed in PC/Cloisite Na⁺ nanocomposites. The observed differences in XRD patterns and TEM images between the two nanocomposite systems are explained by in situ FTIR spectroscopy. The results of rheological measurements (linear dynamic viscoelasticity, non-linear transient shear flow, and steady-state shear flow) support the conclusions drawn from the results of XRD, TEM, and FTIR spectroscopy.     

Facile synthesis and light scattering characteristics of polystyrene/poly(3,4-ethylenedioxythiophene) nanocomposite particles

Polystyrene/poly(3,4-ethylenedioxythiophene) (PS/PEDOT) nanocomposite particles with uniform size and well-defined morphology have been synthesized using the proposed strategy, which involves swelling of 3,4-ethylenedioxythiophene (EDOT) into PS seed particles, followed by its diffusion and polymerization on the PS surface. This process affords much more effective control over the structure and morphology of the resultant nanocomposites by changing the EDOT/PS weight ratio, reaction temperature, and the rate of addition of the doping acid. The PS/PEDOT nanocomposite particles have been extensively characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), elemental microanalyses and X-ray photoelectron spectroscopy (XPS). Furthermore, the correlation between nanostructure of the resultant nanocomposite particle and its electromagnetic response performance (e.g., mass extinction effect in infrared region) was investigated.     

Preparation and characterization of thermoplastic starch–kaolinite nanocomposite films

In this work, the thermoplastic starch–kaolinite (KAO) nanocomposite films were first prepared via solution‐casting method using chitosan‐modified KAO (CKAO) and Na⁺–KAO (NKAO). The structure was investigated by X‐ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy techniques. The results showed that the well‐dispersed KAO layers were delaminated in the starch matrix attesting to anexfoliated nanocomposite and formed strong interaction with starch molecules. According to thermogravimetric analysis, differential scanning calorimetric study, and water absorption testing, the starch–CKAO–urea nanocomposites have the greatest enhancements compared with those of starch–urea film and starch–NKAO–urea nanocomposites. These results provide the important information with using CKAO to obtain the exfoliated starch nanocomposites with high performance. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Investigation of corrosion protection performance of epoxy coatings modified by polyaniline/clay nanocomposites on steel surfaces

In this study, polyaniline (PANI) and polyaniline/clay nanocomposites were prepared via in situ oxidative polymerization. The morphology of nanocomposites structures was investigated by X-ray diffraction (XRD). The chemical structures of PANI and PANI/clay nanocomposites were examined via Fourier transform infrared (FT-IR) spectroscopy. Polyaniline-based pigments were introduced into epoxy paint and applied on steel substrates. The effect of clay addition and the type of clay cation, including Na⁺ in natural clay (MMT) and alkyl ammonium ions in organo-modified montmorillonite (OMMT), on the anticorrosion performance of epoxy-based coatings was investigated through electrochemical Tafel test, electrochemical impedance spectroscopy and immersion measurements in NaCl solution. The stability of the adhesion of the neat and modified epoxy coatings to the steel surface was also examined. The results indicated that introduction of PANI/OMMT nanocomposite into epoxy paint results in improved anticorrosion properties in comparison with PANI/MMT and neat PANI.     

The electrorheological properties of polyaniline nanofiber/kaolinite hybrid nanocomposite

A novel polyaniline nanofiber/kaolinite nanoplatelet hybrid nanocomposite was synthesized by means of rapidly mixed in situ polymerization. The resultant polyaniline/kaolinite hybrid nanocomposite was characterized via different techniques, such as X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results show that 2D clay nanoplatelets are coated by the 1D polyaniline nanofibers. The nanoclay platelets can improve the thermal stability of polyaniline nanofibers. An electrorheological effect is found with the suspension of polyaniline nanofiber/kaolinite nanoplatelet hybrid nanocomposite dispersed in silicone oil. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1104‐1113, 2013     

Synthesis and characterization of new nanocomposites based on epoxy resins and organophilic clays

Epoxy–clay nanocomposites were synthesized using different types of modified montmorillonite, either with a classic quaternary ammonium salt or with protonated adducts synthesized by reacting resorcinol diglycidyl ether with monoamines (benzylamine or cyclohexylamine). The chemical structure was investigated using Fourier transform infrared and ¹H NMR spectrometry. The nanocomposite structures were confirmed using X‐ray diffraction analysis and transmission electron microscopy. The influence of the montmorillonite modifier on the glass transition temperature of the cured composites was studied using dynamic mechanical analysis. Copyright © 2007 Society of Chemical Industry     

Thermomechanical and barrier properties of UV‐cured epoxy/O‐montmorillonite nanocomposites

Mixtures of an epoxy resin and organophilic montmorillonites were subjected to ultraviolet (UV)‐induced photopolymerization. Two types of commercially available nanoclays, namely Cloisite 30B and Cloisite Na⁺, were modified through interaction with organic compatibilizers (dodecylsuccinic anhydride, octadecylamine, octadecyl alcohol, and octadecanoic acid). The modified nanoclays, dispersed in the liquid epoxy resin at 5 wt%, were photopolymerized to get nanocomposite films. The kinetics of the photopolymerization was evaluated by means of real‐time Fourier transform infrared spectroscopy. The modified nanoclays and their nanocomposites were characterized through X‐ray diffractometry; transmission electron microscopy showed the presence of intercalated and partially exfoliated morphologies in the nanocomposites. Thermogravimetric and dynamic‐mechanical analyses showed an increase of the thermal properties and an increase of the glass transition temperatures of the nanocomposites compared with that of the neat UV‐cured resin. Finally, the oxygen barrier properties of nanocomposite films, coated on a polyethyleneterephtalate substrate, were evaluated; the decrease of permeability was correlated with the degree of exfoliation of the nanocomposites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Ethylene–octene copolymer (engage)–clay nanocomposites: Preparation and characterization

In this work, preparation and properties of nanoclay modified by organic amine (octadecyl amine, a primary amine) and Engage (ethylene–octene copolymer)–clay nanocomposites are reported. The clay and rubber nanocomposites have been characterized with the help of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). The X‐ray results suggest that the intergallery spacing of pristine clay increases with the incorporation of the amine. The XRD peak observed in the range of 3–10° for the modified clay also disappears in the rubber nanocomposites at low loading. TEM photographs show exfoliation of the clays in the range of 10–30 nm in Engage. In the FTIR spectra of the nanocomposite, there are common peaks for the virgin rubber as well as those for the clay. Excellent improvement in mechanical properties, like tensile strength, elongation at break, and modulus, is observed on incorporation of the nanoclay in Engage. The storage modulus increases, tan δ peak decreases, and the glass transition temperature is shifted to higher temperature. The results could be explained with the help of morphology, dispersion of the nanofiller, and its interaction with the rubber. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 603–610, 2006     

New Role of Layered Silicates as Phase Transfer Catalyst for In Situ Polymerization of Poly(ethylenetetrasulfide) Nanocomposite

In this study, polyethylenetetrasulfide/montmorillonite nanocomposite (PETS/nanoclay) is synthesized from ethylene dichloride and sodium tetrasulfide monomers by in situ polymerization method. The effect of phase-transfer catalyst (PTC) on polymerization kinetics in addition to the structure of resulting PETS containing nanoclay is investigated. The results show that surface-modified montmorillonites by methyl tallow bis-2-hydroxyethyl quaternary ammonium chloride could properly act as PTC. Therefore, it is demonstrated that the addition of nanoclay as PTC reduces the reaction time and increases the polymerization rate during the production of final nanocomposite. The samples were characterized using Fourier transform infrared and Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nuclear magnetic resonance spectroscopy besides energy-dispersive X-ray spectroscopy (EDS) combined with SEM (SEM–EDX). In addition, thermal behavior of nanocomposite was perused by differential scanning calorimetry and thermogravimetric analysis. XRD and AFM results show proper dispersion of clay in PETS matrix and SEM–EDX results demonstrate suitable distribution of clay in polymer matrix. PETS/nanoclay nanocomposite show a better thermal stability, and also higher glass transition and melt temperature compared to pure polysulfide polymer. The solubility of nanocomposite is also studied and results show that the solubility depends on solvent concentration in addition to reinforcement (nanoclay) deals.     

Rigid PVC/(layered silicate) nanocomposites produced through a novel melt‐blending approach

On the basis of the fusion behavior of poly(vinyl chloride) (PVC), the influence of compounding route on the properties of PVC/(layered silicate) nanocomposites was studied. Four different compounding addition sequences were examined during the melt compounding of PVC with montmorillonite (MMT) clay, including (a) a direct dry mixing of PVC and nanoclay, (b) an addition of nanoclay at compaction, (c) an addition of nanoclay at the onset of fusion, and (d) an addition of nanoclay at equilibrium torque. Both unmodified sodium montmorillonite (Na⁺‐MMT) and organically modified montmorillonite (Org.‐MMT) clays were used, and the effect of the addition sequence of the clay during compounding on its dispersion in the matrix was evaluated by X‐ray diffraction and transmission electron miscroscopy. The surface color change, dynamic mechanical analysis, and flexural and tensile properties of PVC/clay nanocomposites were also studied. The experimental results indicated that both the extent of property improvement and the dispersion of nanoparticles in PVC/(layered silicate) nanocomposites are strongly influenced by the degree of gelation achieved in PVC compounds during processing. The addition of nanoclay to PVC must be accomplished at the onset of fusion, when PVC particles are reduced in size, in order to produce nanocomposites with better nanodispersion and enhanced mechanical properties. Overall, rigid PVC nanocomposites with unmodified clay (Na⁺‐MMT) were more thermally stable and exhibited better mechanical properties than their counterparts with organically modified clay (Org.‐MMT). J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Functional Copolymer/Organo-MMT Nanoarchitectures: XXVI. Fabrication and Characterization of Electrospun Nanofibers from PCL/ODA-MMT and Copolymer-g-PLA/ Ag-MMT Blends

We synthesized poly(?-caprolactone)/octadecyl amine-montmorillonite clay nanocomposite as a matrix polymer by solution intercalative method and new amphiphilic poly(maleic anhydrde-alt-1-octadecene)-g-poly(L-lactic acid)/Ag⁺-montmorillonite clay nanocomposite as a partner polymer by interlamellar graft copolymerization of lactic acid onto anhydride copolymer in the presence of silver salt of montmorillonite clay as catalyst-nanofiller. Novel polymer nanofibers were fabricated by electrospinning of matrix/partner blends with different volume ratios. The nanocomposites and nanofibers were investigated by Fourier transform infrared spectroscopy, thermal gravimetric analysis–differential scanning calorimetry, and scanning electron microscope–transmission electron microscope methods. The diameters, morphologies, and thermal behavior of fibers were strongly depended on the partner-polymer nanocomposites loadings. The fabricated biocompatible and biodegradable nanofibers can be utilized for biomedical and filtration applications.     

Characterization of latex-based isotactic polypropylene/clay nanocomposites

Polypropylene/clay nanocomposite (PCN) containing 1 wt% organo-modified clay was prepared by latex technology, previously successfully applied for preparation of carbon nanotubes (CNTs)/polymer composites. The level of dispersion of organoclay and the microstructure of the resulting PCNs were characterized by means of X-ray diffraction analysis, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The obtained results have demonstrated that the latex technique represents a promising method for preparation of PP/clay nanocomposites with good dispersion of exfoliated nanoclay particles. The influence of clay nanoparticles on nonisothermal crystallization of PCN was investigated by DSC. The crystallization onset temperature of the matrix rises for about 5 °C when crystallizing from the quiescent melt. Improved thermal stability of PP/nanoclay was observed as evaluated by TGA. The dynamic mechanical analysis reveals an increase in storage modulus of PP matrix in the nanocomposites for 30% over a temperature range, indicating an increase in the stiffness of the material with the addition of organically modified clay.