Enhancement of corrosion protection effect of poly(styrene‐co‐acrylonitrile) by the incorporation of nanolayers of montmorillonite clay into copolymer matrix

A series of polymer–clay nanocomposite (PCN) materials that consisted of poly(styrene‐co‐acrylonitrile) (PSAN) and layered montmorillonite (MMT) clay were successfully prepared by effectively dispersing the inorganic nanolayers of MMT clay into the organic PSAN matrix by a conventional in situ thermal polymerization. First of all, organic styrene and AN monomers at a specific feeding ratio were simultaneously intercalated into the interlayer regions of organophilic clay hosts and followed by a typical free‐radical polymerization with benzyl peroxide as initiator. The as‐synthesized PCN materials were subsequently characterized by FTIR spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The as‐prepared PCN materials, in the form of coatings, incorporated with low clay loading (e.g., 1 wt %) on cold‐rolled steel, were found to be much superior in corrosion protection over those of bulk PSAN based on a series of standard electrochemical measurements of corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Molecular weights of PSAN extracted from PCN materials and bulk PSAN were determined by gel permeation chromatography with THF as eluant. Effects of the material composition on the molecular barrier and thermal stability of PSAN along with PCN materials, in the form of both membrane and fine powder, were also studied by molecular permeability analysis, differential scanning calorimetry, and thermogravimetric analysis, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2269–2277, 2004     

Polyacrylamide–clay nanocomposite materials prepared by photopolymerization with acrylamide as an intercalating agent

A series of nanocomposite materials consisting of water‐soluble polyacrylamide (PAA) and layered montmorillonite (MMT) clay platelets were prepared by the effective dispersion of the inorganic nanolayers of the MMT clay in the organic PAA matrix via in situ ultraviolet‐radiation polymerization. The acrylamide monomers functioned as both the intercalating agent and the reacting monomers. As a representative procedure for the preparation of the nanocomposites, organic acrylamide monomers were first intercalated into the interlayer regions of acrylamide‐treated organophilic clay hosts, and this was followed by one‐step ultraviolet‐radiation free‐radical polymerization with benzil as a photoinitiator. The as‐prepared polyacrylamide–clay nanocomposite (PCN) materials were subsequently characterized by Fourier transform infrared spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The effects of the material composition on the thermal stability, optical clarity, and gas‐barrier properties of pristine PAA and PCN materials, in the forms of fine powders and membranes, were also studied by differential scanning calorimetry, thermogravimetric analysis, ultraviolet–visible transmission spectroscopy, and gas permeability analysis. The molecular weights of PAA extracted from PCN materials and pristine PAA were determined by gel permeation chromatography with tetrahydrofuran as an eluant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3489–3496, 2004     

Effective enhancement of anticorrosive properties of polystyrene by polystyrene–clay nanocomposite materials

A series of polymer–clay nanocomposite (PCN) materials consisting of polystyrene (PS) and layered montmorillonite (MMT) clay was prepared by effectively dispersing the inorganic nanolayers of MMT clay in the organic PS matrix via in situ thermal polymerization. Organic styrene monomers were first intercalated into the interlayer regions of organophilic clay hosts, followed by a typical free radical polymerization with BPO as the initiator. The as‐synthesized PCN materials were characterized by infrared spectroscopy (IR), wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in anticorrosion to those of bulk PS, based on a series of electrochemical measurements of corrosion potential, polarization resistance and corrosion current in a 5 wt % aqueous NaCl electrolyte. The molecular weights of PS extracted from PCN materials and bulk PS were determined by gel permeation chromatography (GPC) with tetrahydrofuran (THF) as the eluent. The effects of material composition on molecular barrier and thermal stability of PS and PCN materials, in the form of both free‐standing films and fine powders, were also studied by molecular permeability analysis, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1970–1976, 2004     

Enhanced corrosion protection coatings prepared from soluble electronically conductive polypyrrole‐clay nanocomposite materials

A series of electronically conductive nanocomposite materials that consisted of soluble polypyrrole (PPY) and layered montmorillonite (MMT) clay platelets were prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PPY matrix via an in situ oxidative polymerization with dodecylbenzene sulfonic acid (DBSA) as dopant. Organic pyrrole monomers were first intercalated into the interlayer regions of organophilic clay hosts and followed by a one‐step oxidative polymerization. The as‐synthesized electronically conductive polypyrrole–clay nanocomposite (PCN) materials were then characterized by Fourier transformation infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD), and transmission electron microscopy (TEM). PCNs in the form of coatings with low clay loading (e.g., 1.0 wt %) on cold‐rolled steel (CRS) were found to exhibit much better in corrosion protection over those of pristine PPY based on a series of electrochemical measurements including corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Effects of the material composition on the thermal stability, optical properties, and electrical conductivity of pristine PPY along with PCN materials, in the form of fine powder, powder‐pressed pellet, and solution, were also studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), UV‐visible absorption spectra, and four‐point probe technique, respectively. The viscosity of PPY existed in PCN materials and pristine PPY were determined by viscometric analysis with m‐cresol as solvent. The heterogeneous nucleating effect of MMT clay platelets in PPY matrix was studied by wide‐angle powder XRD. The corresponding morphological images of the nucleating behavior of clay platelets in PPY matrix were investigated by scanning electron microscopy (SEM). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3264–3272, 2003     

Poly(N‐vinylcarbazole)–clay nanocomposite materials prepared by photoinitiated polymerization with triarylsulfonium salt initiator

A series of polymer–clay nanocomposite (PCN) materials that consist of poly(N‐vinylcarbazole) (PNVC) and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT in an organic PNVC matrix via in situ photoinitiated polymerization with triarylsulfonium salt as the initiator. Organic NVC monomers are first intercalated into the interlayer regions of the organophilic clay hosts, followed by one‐step UV‐radiation polymerization. The as‐synthesized PCN materials are typically characterized by Fourier transform IR spectroscopy, wide‐angle X‐ray diffraction, and transmission electron microscopy. The molecular weights of PNVCs extracted from the PCN materials and the bulk PNVC are determined by gel permeation chromatography analysis with tetrahydrofuran as the eluant. The morphological image of the synthesized materials is observed by an optical polarizing microscope. The effects of the material composition on the optical properties and thermal stability of PNVCs and a series of PCN materials (solution and fine powder) are also studied by UV–visible absorption spectra measurements, thermogravimetric analysis, and differential scanning calorimetry, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1904–1912, 2004     

Enhanced corrosion prevention effect of polysulfone–clay nanocomposite materials prepared by solution dispersion

A series of polymer–clay nanocomposite (PCN) materials containing polysulfone (PSF) and layered MMT clay were successfully prepared by effectively dispersing inorganic nanolayers of MMT clay in an organic PSF matrix via a solution dispersion technique. The synthesized PCN materials were subsequently investigated with a series of characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The prepared PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in corrosion prevention to those of bulk PSF, based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current and electrochemical impedance spectroscopy (EIS) in a 5 wt % aqueous NaCl electrolyte. The effects of material composition on the molecular barrier, mechanical strength and optical clarity of PSF and PCN materials, in the form of membranes, was also studied by molecular permeability analysis (GPA), dynamic mechanical analysis (DMA) and UV‐Visible transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 631–637, 2004     

Preparation and properties of heterocyclically conjugated poly(3‐hexylthiophene)–clay nanocomposite materials

A series of heterocyclically conjugated polymer–clay nanocomposite (PCN) materials that consisted of organic poly(3‐hexylthiophene) (P3HT) and inorganic montmorillonite (MMT) clay platelets were prepared by in situ oxidative polymerization with FeCl₃ as an oxidant. The as‐synthesized PCN materials were characterized by Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (WAXRD), and transmission electron microscopy (TEM). The effects of the material composition on the anticorrosion, gas barrier, thermal stability, flammability, mechanical strength, and electrical conductivity properties of the P3HT and PCN materials were studied by electrochemical corrosion measurements, gas‐permeability analysis (GPA), thermogrametric analysis (TGA), limiting oxygen index (LOI) measurements, dynamic mechanical analysis (DMA), and a four‐point probe technique, respectively. The molecular weights of extracted and bulk P3HT were determined by gel permeation chromatography (GPC) with THF as an eluant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3438–3446, 2004     

Preparation and properties of (BATB–ODPA) polyimide–clay nanocomposite materials

A series of polymer–clay nanocomposite (PCN) materials consisting of 1,4‐bis(4‐aminophenoxy)‐2‐tert‐butylbenzene–4,4′‐oxydiphthalic anhydride (BATB–ODPA) polyimide (PI) and layered montmorillonite (MMT) clay were successfully prepared by an in situ polymerization reaction through thermal imidization up to 300°C. The synthesized PCN materials were subsequently characterized by Fourier‐Transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of material composition on thermal stability, mechanical strength, molecular permeability and optical clarity of bulk PI and PCN materials in the form of membranes were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), molecular permeability analysis (GPA) and ultraviolet‐visible (UV/VIS) transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1072–1079, 2004     

Studies on heterogeneous nucleation effect of dispersing intercalated montmorillonite clay platelets in polyaniline matrix

In this article, a series of nanocomposite materials that consisted of emeraldine base (EB) of polyaniline (PANI) and montmorillonite (MMT) clay were prepared by effectively dispersing the inorganic MMT clay platelets into organic PANI matrix via in situ chemically oxidative polymerization. Organic aniline monomers were first intercalated into the interlayer regions of organophilic clay hosts and followed by an one‐step oxidative polymerization with ammonium persulfate as oxidant. The as‐synthesized PANI‐clay nanocomposite (PCN) materials were characterized by Fourier‐Transformation infrared spectroscopy and transmission electron microscopy. It should be noted that the EB of PANI in the presence of dispersed intercalated MMT clay platelets was found to display an observable enhancement in polymer crystallinity as compared with that of neat PANI based on series of investigations of wide‐angle powder X‐ray diffraction patterns and differential scanning calorimetric studies. This remarkable increase of polymer crystallinity might be resulted from the effective heterogeneous nucleation effect of dispersed clay platelets existed in PCN materials. The surface morphology study of PCN materials was further evaluated by polarizing optical microscopy, scanning electron microscopy, and atomic force microscopy. POLYM. COMPOS., 31:2049–2056, 2010. © 2010 Society of Plastics Engineers     

High‐performance polyimide–clay nanocomposite materials based on a dual intercalating agent system

BACKGROUND: Polymer–clay nanocomposites (PCNs) have attracted considerable interest in recent years owing to their unique physical and chemical properties that lead to a wide range of applications. A series of PCN materials consisting of polyimide and layered montmorillonite (MMT) clay were successfully prepared by in situ polymerization. RESULTS: Silicate layers are better dispersed in polymer matrices when dual intercalating agents (hexadecyltrimethylammonium bromide–4,4′‐oxydianiline) are applied for MMT modification according to wide‐angle X‐ray diffraction and transmission electron microscopy studies. Effects of single and dual intercalating agents on thermal stability, mechanical strength and the molecular barrier of PCN materials consisting of organo‐modified MMT were studied by means of thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analyses, gas permeability analysis and vapor permeability analysis. CONCLUSION: Improved thermal and mechanical stabilities, as well as barrier properties were observed for the PCN materials containing dual intercalating agent‐modified MMT. Copyright © 2008 Society of Chemical Industry     

Synthesis and dielectric properties of poly(methyl methacrylate)–clay nanocomposite materials

Poly(methyl methacrylate) (PMMA)–clay nanocomposite (PCN) materials were synthesized through in situ intercalative polymerization. A cationic surfactant, [2(dimethylamino)ethyl]triphenylphosphonium bromide, was used as an intercalating agent with pristine Na⁺‐montmorillonite (MMT). The synthesized PCN materials were subsequently investigated by a series of characterization techniques, including wide‐angle powder X‐ray diffraction, Fourier transform IR spectroscopy, transmission electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Compared to pure PMMA, the PCN materials exhibit higher thermal degradation temperatures and glass‐transition temperatures. The dielectric properties of PCN blending with a commercial PMMA material in film form with clay loading from 0.5 to 5.0 wt % were measured under frequencies of 100 Hz–1 MHz at 35–100°C. Significantly depressed dielectric constants and losses were observed for these PCN‐blending materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2175–2181, 2005     

Synthesis and characterization of some polyacrylate/montmorillonite nanocomposites by in situ emulsion polymerization using redox initiation system

Intercalated modification of Montmorillonite clay (MMT) with three different amino acids—Alanine, Leucine, and Phenylalanine—in the presence of hydrochloric acid followed by surface modification by methyl triethoxy silane coupling agent to produce double modified Montmorillonite clay which is characterized by X‐ray diffraction (XRD) and Thermogravimetric analysis (TGA). The data shows an increase in d‐spacing of modified clay as a result of cationic exchange. Double modified MMT clay was used in the preparation of Polyacrylate/clay nanocomposites by using an in situ redox emulsion polymerization of polyglycidylmethacrylate (PGMA) and polymethylmethacrylate (PMMA). The structure and properties of the prepared nanocomposites were achieved by XRD, TGA, and SEM. The results show that all weight loses temperatures for the nanocomposite samples are higher than that of pure polymer in both PGMA and PMMA. It is also obvious that the increasing in the clay content plays an effective role in the increasing of thermal stability of these materials. SEM shows that the clay is more homogenously dispersed in PMMA than in PGMA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of polyimide–clay nanocomposite materials for anticorrosion application

A series of polymer–clay nanocomposite (PCN) materials that consist of organosoluble polyimide and layered montmorillonite clay were prepared by the solution dispersion technique. The organosoluble polyimide containing non‐coplanar moiety in diamine monomer and flexible bridging linkages in dianhydride monomer was synthesized by chemical imidization. The as‐synthesized PCN materials were characterized by infrared spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The organosoluble polyimide showed better corrosion resistance compared to polyaniline, poly(o‐ethoxyaniline) and poly(methyl methacrylate) by using a series of standard electrochemical corrosion measurements of corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Polyimide–clay nanocomposite materials incorporated with low loading of clay were found to further improve corrosion inhibition over pure polyimide. Effects of the material composition on the O₂/H₂O molecular permeability, optical clarity, and thermal properties of polyimide–clay nanocomposite materials were studied by molecular permeability analysis, UV–visible transmission spectra, thermogravimetric analysis, and differential scanning calorimetry, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3573–3582, 2004     

Structure and properties of poly(o‐methoxyaniline)–clay nanocomposite materials

In this study, we prepared a series of polymer–clay nanocomposite (PCN) materials that consisted of an emeraldine base of poly(o‐methoxyaniline) and layered montmorillonite. Organic o‐methoxyaniline monomers were first intercalated into the interlayer regions of organophilic clay hosts followed by a one‐step in situ oxidative polymerization. The as‐synthesized PCN materials were subsequently characterized by FTIR spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The molecular weights of PMA extracted from PCN materials and bulk PMA were determined by GPC with THF as eluant. Effects of the material composition on the thermal stability, flame resistance, electrical conductivity, and corrosion inhibition performance of PMA, along with a series of PCN materials in the form of fine powder and coating, were also studied by TGA, limiting oxygen index measurements, four‐point probe technique, and electrochemical corrosion measurements, respectively. Morphological images of as‐synthesized materials were also investigated by SEM. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1072–1080, 2003     

Poly(methyl methacrylate)/clay nanocomposites by photoinitiated free radical polymerization using intercalated monomer

A series of poly(methyl methacrylate)/montmorillonite (PMMA/MMT) nanocomposite were prepared by successfully dispersing the inorganic nanolayers of MMT clay in an organic PMMA matrix via in situ photoinitiated free radical polymerization. Methyl methacrylate monomer was first intercalated into the interlayer regions of organophilic clay hosts by “click” chemistry followed by a typical photoinitiated free radical polymerization. The intercalated monomer was characterized by FT-IR spectroscopy, elemental analysis and thermogravimetric analysis methods. The intercalation ability of the modified monomer and exfoliated nanocomposite structure were confirmed by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Thermal stability of PMMA/MMT nanocomposites was also studied by both differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).     

An in situ intercalative polymerization method for preparing UV curable clay–polymer nanocomposites

A novel in situ intercalative polymerization technique was used to disperse clay mineral in a precursor resin for use in UV curing by performing an in situ ion exchange reaction during polyesterification. Unmodified montmorillonite (MMT) was added to a reaction mixture composed of monomers and methyl, tallow, bis‐2‐hydroxyethyl ammonium (MTEtOH) during the synthesis of unsaturated polyesters to create resins containing highly dispersed, organically modified MMT. UV‐curable clay–polymer nanocomposite (CPN) films were then prepared utilizing donor–acceptor chemistry through reactions of the unsaturated polyester resin with triethylene glycol divinyl ether. Functional group conversion improved up to 15% by the incorporation of clay mineral into the polymer matrix through the in situ polymerization method. The CPNs also had improved barrier, mechanical, and thermal properties over a control film containing no clay mineral. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42601.     

Synthesis and characterization of poly(methyl methacrylate)/montmorillonite nanocomposites by in situ bulk polymerization

Poly(methyl methacrylate)/montmorillonite (MMT) nanocomposites were prepared by in situ bulk polymerization. The results showed that the silicone coupling agent affected the structure and properties of hybrid materials. XRD analysis showed that the dispersion of clay in nanocomposites with silicone‐modified organophilic MMT was more ordered than that in nanocomposites with unmodified organophilic MMT. The glass transition temperature (T_g) of the nanocomposites was 6–15°C higher and the thermal decomposition temperature (T_d) was 100–120°C higher than those of pure PMMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2256–2260, 2003     

Preparation of polystyrene–clay nanocomposites via dispersion polymerization using oligomeric styrene‐montmorillonite as stabilizer

This study describes the preparation of polystyrene–clay nanocomposite (PS‐nanocomposite) colloidal particles via free‐radical polymerization in dispersion. Montmorillonite clay (MMT) was pre‐modified using different concentrations of cationic styrene oligomeric (‘PS‐cationic’), and the subsequent modified PS‐MMT was used as stabilizer in the dispersion polymerization of styrene. The main objective of this study was to use the clay platelets as fillers to improve the thermal and mechanical properties of the final PS‐nanocomposites and as steric stabilizers in dispersion polymerization after modification with PS‐cationic. The correlation between the degree of clay modification and the morphology of the colloidal PS particles was investigated. The clay platelets were found to be encapsulated inside PS latex only when the clay surface was rendered highly hydrophobic, and stable polymer latex was obtained. The morphology of PS‐nanocomposite material (after film formation) was found to range from partially exfoliated to intercalated structure depending on the percentage of PS‐MMT loading. The impact of the modified clay loading on the monomer conversion, the polymer molecular weight, the thermal stability and the thermomechanical properties of the final PS‐nanocomposites was determined. Copyright © 2012 Society of Chemical Industry     

Improving the physical properties of PEA/PMMA blends by the uniform dispersion of clay platelets

Poly(ethyl acrylate) (PEA)/poly(methyl methacrylate) (PMMA) emulsion blends that were combined with unmodified montmorillionite (MMT) to improve the physical properties via nanocomposite formation. We prepared a cationic PEA/PMMA latex and used a heterocoagulation process to create a homogeneous dispersion of the clay platelets in the matrix. The cationic PEA/PMMA emulsion blends were prepared using a cationic initiator in the presence of free surfactant, cetyl trimethylammonium bromide (CTABr), followed by mixing with an aqueous slurry of MMT. The PEA/PMMA-MMT nanocomposites could be processed at low temperatures. Low temperature processing prevented the commonly observed discoloration associated with many thermoplastic nanocomposites. DSC, SAXS, TEM and AFM were used to study the dispersion of MMT and morphology of PEA/PMMA-MMT nanocomposites. Tensile stress, elongation at break and Young's modulus demonstrated a significant reinforcing effect of clay.     

A one‐pot method to prepare transparent poly(methyl methacrylate)/montmorillonite nanocomposites using imidazolium‐based ionic liquids

Poly(methyl methacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by a new one‐pot technique, where the hydrophilic Na‐MMT layers were decorated with hydrophobic 1‐dodecyl‐3‐methylimidazolium hexafluorophosphate (C₁₂mimPF₆) ionic liquid in situ during melt blending with PMMA and intercalation of polymer chains took place subsequently. The in situ modification and intercalation of Na‐MMT were confirmed using X‐ray diffraction and transmission electron microscopy. The combination of the compatible C₁₂mimPF₆ with PMMA and the good dispersion of MMT layers at the nanoscale rendered the resultant PMMA/MMT nanocomposites with improved optical transparency, thermal stability and mechanical properties. Copyright © 2012 Society of Chemical Industry