The effect of chemical modification on the fracture toughness of montmorillonite clay/epoxy nanocomposites

The change in fracture toughness and its dependence on the content of clay nanoplatelets and adhesion at the interface between clay nanoplatelets and anhydride-cured epoxy matrix are discussed. Three clay nanoplatelets with different chemical modifications were used in this investigation. To fabricate nanocomposites, the clay nanoplatelets were sonicated in acetone for 2 h. The role of the clay nanoplatelets in the mechanical/fracture properties was investigated by transmission electron microscopy (TEM). Bright-field TEM micrographs showed excellent dispersion of clay nanoplatelets in epoxy matrix. Both intercalation and exfoliation of clay nanoplatelets were observed depending on clay modification. Compact tension specimens were used for fracture testing. The fracture toughness increased with increasing clay content. The fracture toughness of clay/epoxy nanocomposites varied with the clay morphology in the epoxy matrix. Different morphologies of the fracture surfaces, highly dependent on the morphology of dispersed clay nanoplatelets, were observed using environmental scanning electron microscopy (ESEM). The fracture toughness was found to be correlated with the fracture surface roughness measured by confocal laser scanning microscopy (CLSM).     

Continuous process for melt intercalation of PP–clay nanocomposites with aid of power ultrasound

A continuous ultrasound‐assisted process using a single screw extruder with an ultrasonic attachment was developed to prepare PP/clay nanocomposites of varying clay concentrations. The feed rate that controlled the residence time of the polymer in the ultrasonic treatment zone was varied. Die pressure and power consumption were measured. Rheological properties, morphology, and mechanical properties of the untreated and ultrasonically treated nanocomposites were studied. An intercalation of polymer molecules into clay galleries and a partial exfoliation, which occur at short residence times (of the order of seconds), were observed as evident from measurements by X‐ray diffraction and transmission electron microscopy. The obtained results indicate a possibility of the rapid intercalation and partial exfoliation of PP/clay nanocomposites without the matrix being chemically modified. J. VINYL. ADDIT. TECHNOL. 12:78–82, 2006. © 2006 Society of Plastics Engineers.     

Effect of ethylene glycidyl methacrylate compatibilizer on the structure and mechanical properties of clay nanocomposites modified with ethylene vinyl acetate copolymer

The structure and mechanical properties of clay modified with ethylene vinyl acetate copolymer in the presence of ethylene glycidyl methacrylate (EGMA) were investigated as a function of compatibilizer and clay contents. The structure and properties were determined by X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). The presence of EGMA caused strong exfoliation of the clay in the polymer matrix, although at higher clay contents, some clay layers still existed. The more effective exfoliation, however, did not seem to substantially influence the tensile properties of the nanocomposites because the EGMA itself had a much stronger influence, which overshadowed any possible influence that the EGMA–clay interaction may have had on these properties. The thermal stability of the nanocomposites (as studied by TGA) improved in the presence of EGMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4095–4101, 2007     

Reinforcing effect of organoclay in rubbery and glassy epoxy resins,part 1: Dispersion and properties

The reinforcing effect of organoclay in two epoxy matrices, one rubbery and one glassy, was studied. The rubbery and glassy epoxy matrices were chosen to have a very similar chemistry to minimize its impact on the comparison of properties. The epoxy resin was EPON? 828, and the two hardeners were amine‐terminated polyoxypropylene diols, having different average molecular weights (MW) of 2000 and 230 g/mol, namely Jeffamine® D‐2000 and Jeffamine® D‐230, respectively. The nanocomposites were prepared with the organoclay Cloisite® 30B from Southern Clay Products. The quality of dispersion and intercalation/exfoliation was analyzed by means of X‐ray diffraction (XRD), field emission gun scanning electron microscopy (FEGSEM), and transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the curing reactivity and the thermal stability of the epoxy resin systems, respectively. Tensile properties and hardness of epoxy resin and epoxy nanocomposites were measured according to ASTM standards D638‐02 and D2240‐00, respectively. Fracture surfaces were also analyzed by FEGSEM. These two epoxy systems as well as their nanocomposites display totally different physical and mechanical behavior. It is found that the quality of clay dispersion and intercalation/exfoliation, and the mechanical behavior of the glassy and rubbery epoxy nanocomposites are distinct. The results also indicate that the presence of the clay does not significantly affect the T_g of either the rubbery or the glassy epoxy; however, the fracture surface and mechanical properties were found to be influenced by the presence of nanoclay. Finally, several different reinforcing mechanisms are proposed and discussed for the rubbery and glassy epoxy nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Thermoplastic elastomeric nanocomposites from poly[styrene–(ethylene‐co‐butylene)–styrene] triblock copolymer and clay: Preparation and characterization

Thermoplastic elastomer (TPE)–clay nanocomposites based on poly[styrene–(ethylene‐co‐butylene)–styrene] triblock copolymer (SEBS) were prepared. Natural sodium montmorillonite (MMT) clay was organically modified by octadecyl amine to produce an amine‐modified hydrophobic nanoclay (OC). Commercially available Cloisite 20A (CL20) and Cloisite 10A, tallow ammine modified nanoclays, were also used. The intergallery spacing of MMT increased on amine modification as suggested by the shifting of the X‐ray diffraction (XRD) peak from 7.6 to 4.5 and 3.8° in the cases of OC and CL20, respectively. The latter demonstrated no XRD peak when it was used at 2 and 4 parts phr in the SEBS system. Transmission electron microscopy studies showed the intercalation–exfoliation morphology in SEBS containing 4 parts of CL20₄–SEBS, agglomeration in SEBS having 4 parts of MMT, and mixed morphology in SEBS with 4 parts of OC systems. Locations of the clay particles were indicated by the atomic force micrographs. Mechanical and dynamic mechanical thermal analysis studies confirmed the best properties with the CL20₄–SEBS nanocomposites. Significant improvements in mechanical properties such as tensile strength, modulus, work to break, and elongation at break were achieved with the CL20₄–SEBS in polymer‐layered silicate nanocomposites. Dynamic mechanical studies further showed the affinity of the organoclays toward both segments of the TPE and a compatibilization effect with CL20 at a 4‐phr loading. Atomic force microscopy showed distinctly different morphologies in nanocomposites prepared through solution and melt processing. Comparisons of the mechanical, dynamic mechanical, and morphological properties of the nanocomposites prepared by melt and solution intercalation processes were done. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2040–2052, 2006     

Curing kinetics and mechanical properties of epoxy nanocomposites based on different organoclays

The effect of different organoclays and mixing methods on the cure kinetics and properties of epoxy nanocomposites based on Epon828 and Epicure3046 was studied. The two kinds of organoclay used in this study, both based on natural montmorillonite but differing in intercalant chemistry, were I.30E (Nanomer I.30E—treated with a long‐chain primary amine intercalant) and C.30B (Cloisite 30B—treated with a quaternary ammonium intercalant, less reactive with epoxy than the primary amine). The two mixing processes used to prepare the nanocomposites were (i) a room‐temperature process, in which the clay and epoxy are mixed at room temperature, and (ii) a high‐temperature process, in which the clay and epoxy are mixed at 120°C for 1 h by means of mechanical mixing. The nanocomposites were cured at room temperature and at high temperature. The quality of dispersion and intercalation/exfoliation were analyzed by scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction. The heat evolution of the epoxy resin formulation and its nanocomposite systems was measured using differential scanning calorimetry at different heating rates of 2.5, 5, 10, 15, and 20°C min^?1. The cure kinetics of these systems was modeled by means of different approaches. Kissinger and isoconversional models were used to calculate the kinetics parameters while the Avrami model was utilized to compare the cure behavior of the epoxy systems. The cure kinetics and mechanical properties were found to be influenced by the presence of nanoclay, by the type of intercalant, and by the mixing method. POLYM. ENG. SCI., 47:649–661, 2007. © 2007 Society of Plastics Engineers.     

The effect of clay type and of clay–masterbatch product in the preparation of polypropylene/clay nanocomposites

Clay containing polypropylene (PP) nanocomposites were prepared by direct melt mixing in a twin screw extruder using different types of organo‐modified montmorillonite (Cloisite 15 and Cloisite 20) and two masterbatch products, one based on pre‐exfoliated clays (Nanofil SE 3000) and another one based on clay–polyolefin resin (Nanomax‐PP). Maleic anhydride‐grafted polypropylene (PP‐g‐MA) was used as a coupling agent to improve the dispersability of organo‐modified clays. The effect of clay type and clay–masterbatch product on the clay exfoliation and nanocomposite properties was investigated. The effect of PP‐g‐MA concentration was also considered. Composite morphologies were characterized by X‐ray diffraction (XRD), field emission gun scanning electron microscopy (FEG‐SEM), and transmission electron microscopy (TEM). The degree of dispersion of organo‐modified clay increased with the PP‐g‐MA content. The thermal and mechanical properties were not affected by organo‐modified clay type, although the masterbatch products did have a significant influence on thermal and mechanical properties of nanocomposites. Intercalation/exfoliation was not achieved in the Nanofil SE 3000 composite. This masterbatch product has intercalants, whose initial decomposition temperature is lower than the processing temperature (T ～ 180°C), indicating that their stability decreased during the process. The Nanomax‐PP composite showed higher thermal and flexural properties than pure PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of melt processing conditions on mechanical properties of polyvinylchloride/organoclay nanocomposites

Abstract

Polyvinylchloride compositions have been prepared by the melt intercalation method using a single screw extruder. Different types of nanofiller based on natural sodium montmorillonite were tested. In particular, intercalating agents containing amine groups combined with co-intercalating agent (low or high molecular weight plasticiser) were examined to determine which is the most suitable not only for producing the largest basal spacing and subsequently the best exfoliation of clay tactoids in polymer matrix, but also for the highest beneficial influence on mechanical properties. In the case of improved exfoliation, the effect of compounding was investigated. Therefore, three values of screw speed were studied and some blends were compounded twice to study the retention time in a single screw extruder and the influence on orientation, dispersion and exfoliation of clay particles in the PVC matrix. Moreover, the effect of different types of plasticiser on mechanical properties was also studied. Bis(2-ethylhexyl) phthalate, Bis(2-ethylhexyl) adipate and Lankroflex epoxy plasticiser were tested. Dynamical thermo-mechanical properties were examined and the tensile properties of thin PVC sheets prepared by calendaring. Using X-ray diffraction and transmission electron microscopy, it was found that partially intercalated and disordered structures arose in polyvinylchloride composites containing sodium montmorillonite, while a fine dispersion of partial exfoliation of individual montmorillonite layers in polyvinylchloride matrix was observed when this clay was organically modified. Finally, the value of the tensile modulus for PVC nanocomposites containing as little as 5 wt-% montmorillonite was increased three times provided that the optimum melt processing conditions were used.     

Fracture behavior of core‐shell rubber–modified clay‐epoxy nanocomposites

Morphology and fracture mechanisms in two nanoclay‐filled epoxy systems were investigated using both microscopy and spectroscopy tools. Clay exfoliation was achieved using a series of sample preparation steps, and confirmed using wide angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Significant improvement in modulus was obtained when clay exfoliation was achieved. Incorporation of core‐shell rubber (CSR) in both caly‐filled epoxy systems leads to greatly enhanced fracture toughness. Optical microscopy and TEM observations of the CSR‐modified nanocomposites suggest that CSR cavitation. shear yielding of the matrix, clay layer delamination. CSR bridging, crack bifurcation. and crack deflection are among the operative toughening mechanisms observed, depending on the nature of the epoxy matrix utilized.     

The influence of clay and elastomer concentration on the morphology and fracture energy of preformed acrylic rubber dispersed clay filled epoxy nanocomposites

The influence of toughener and clay concentration on the morphology and mechanical properties of three-phase, rubber-modified epoxy nanocomposites was studied. Nanocomposite samples were prepared by adding octadecyl ammonium ion exchanged clay to a dispersion of pre-formed acrylic rubber particles in liquid epoxy, so as to minimize alteration to the rubber morphology in the final cured specimen. The state of clay platelet exfoliation and rubber dispersion in the cured nanocomposites was studied using transmission electron microscopy. The amounts of clay platelet separation and dispersion of clay aggregates in the epoxy matrix were found to be sensitive to clay and toughener concentration, and clay platelets preferentially adsorb to the rubber particles. Tensile modulus and strength increase and ductility decreases with increasing organoclay content, while rubber has the opposite effects on the properties of epoxy resin. When both additives are present in epoxy resin, a favorable combination is produced: ductility is enhanced without compromising modulus and strength. Modulus and strength are improved by nano and micro dispersion of nanoclay in the epoxy matrix, whereas elongation and toughness are improved by clay adsorption to the rubber particle surface, which promotes cavitation. The glass transition temperature of epoxy resin remains relatively unchanged with clay addition.     

Water‐blown polyurethane–clay nanocomposite foams from biopolyol—effect of nanoclay on the properties

The present work deals with the development of polyurethane–clay nanocomposite foams by replacing part of the synthetic polyol with castor oil derivative. Hydroxylated castor oil was converted into diethanol amide by transamidation and the resulting polyol was formulated into water‐blown foams. Modified montmorillonite clay was used as nanofiller in different amounts viz. 0.5%, 1.0%, 2.0%, and 5.0% by total weight of the foam formulation. Rheological measurements on the polyol–clay mixtures indicated that up to 1% clay loading there is no significant change in the viscosity with shear rate and beyond 2%, shear thinning occurred. X‐ray diffraction studies further substantiated these results. The effect of the modified clay on the density, mechanical properties such as compression strength, compression modulus, and microstructure of the foams were investigated. The filler thus added had a reinforcing effect on the foam as observed in the density and compression strength measurements. Differential scanning calorimetric studies on T_g and dynamic mechanical analyses on the modulus clearly indicated that 1% clay loading and above led to exfoliation and plasticizing effect. Exfoliated nanocomposites in compositions containing 1% clay and more yielded a much higher nucleation rate than intercalated ones leading to reduced cell size as observed by optical and scanning electron microscopy. Thus, castor oil, which is readily available, relatively inexpensive, and environmentally benign nonedible oil, has been successfully used to prepare filled semirigid foams which can find application in insulation and packing. POLYM. COMPOS. 34:1306–1312, 2013. © 2013 Society of Plastics Engineers     

Comparative effect of metallocene and Ziegler‐Natta polypropylene on the exfoliation of montmorillonite and hectorite clays to obtain nanocomposites

The present study was carried out on the effect of molecular weight and polydispersity of polypropylene (PP) obtained via Ziegler‐Natta or metallocene catalysis on the formation of nanocomposites with montmorillonite and mineral and synthetic hectorite. The formation of the nanocomposites was achieved by the melt‐mix method. X‐ray diffraction, transmission electron microscopy, and analysis of mechanical properties showed that, using PP obtained via metallocene catalysis (polydispersity ～ 2), it is possible to achieve improved formation of nanocomposites compared with PP obtained via Ziegler‐Natta catalysis (polydispersity ～ 4). It was also found that the molecular weight of the PP affects the tendency toward clay exfoliation and consequently the properties of the nanocomposites. Montmorillonite type clay was evaluated at 1%, 3%, and 5% by weight in the nanocomposite. The nanocomposite with 1 wt % clay was found to have better mechanical properties compared with the nanocomposite containing 3 wt % and 5 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 698–706, 2007     

Epoxy resin/exfoliated clay hybrid materials with high thermal properties

A new type of organophilic clay grafted with the protonated 4, 4′-methylenediamine was prepared. The epoxy was modified using the organophilic clay and was prepared by “acetone-clay slurry” method. The morphology of the clay platelets into epoxy matrix were characterized by wide angle X-ray diffraction and transmission electron microscopy. The results indicated that the epoxy resin/exfoliated clay hybrid materials were successfully prepared and the exfoliation of clay into epoxy matrix occurred in the curing process. The excellent thermal mechanical properties of the hybrid materials with the values of the storage modulus and glass transition temperature (T_g) of the hybrid materials were studied by dynamic mechanical analysis. When 7 wt% of modified clay was added into epoxy, the storage modulus of hybrid materials increased to 1131 MPa at 110°C, and 51 MPa at 220°C in comparison to the pristine cured epoxy (661 MPa at 110°C and 6 MPa at 220°C). The high thermal stabilities of the hybrid materials especially in high temperature were also been researched by thermogravimetric analysis. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Curing behavior and structure of an epoxy/clay nanocomposite system

The curing behavior of an epoxy/clay nanocomposite system composed of a bifunctional epoxy resin with an aromatic amine curing agent and an organically modified clay was investigated. Differential scanning calorimetry (DSC) was used to investigate the curing behavior of the epoxy/clay nanocomposite system. The curing rate of the nanocomposite system increased with increasing clay content. A kinetic equation, considering an autocatalytic reaction mechanism, could describe fairly well the curing behavior of the epoxy/clay nanocomposite system. The reaction kinetic parameters of the kinetic equation were determined by fitting DSC conversion data to the kinetic equation, using a nonlinear numerical method. Dynamic mechanical analysis was used to investigate the thermomechanical properties of the epoxy/clay nanocomposite system. The glass transition temperature of the epoxy/clay nanocomposite system increased slightly with increasing clay content. The structure of the nanocomposite system was characterized by X‐ray diffraction analysis and transmission electron microscope imaging. The formation of intercalated structures was observed dominantly in the epoxy/clay nanocomposites, together with some exfoliated structures. POLYM. ENG. SCI., 46:1318–1325, 2006. © 2006 Society of Plastics Engineers     

Chitosan/clay nanocomposite film preparation and characterization

Nanocomposites of chitosan and nanoclays (MMT‐Na⁺ and Cloisite 30B) were prepared by solvent casting. The structural properties, thermal behaviors, and mechanical properties were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy, differential scanning calorimetry, thermogravimetry analyses, and an Instron universal testing machine. XRD and TEM results indicated that an exfoliated structure was formed with addition of small amounts of MMT‐Na⁺ to the chitosan matrix. Intercalation along with some exfoliation occurred with up to 5 wt % MMT‐Na⁺. Micro‐scale composite (tactoids) formed when Cloisite 30B was added to the chitosan matrix. Surface roughness increased with addition of a small amount of clay. Tensile strength of a chitosan film was enhanced and elongation‐at‐break decreased with addition of clay into the chitosan matrix. Melt behavior and thermal stability did not change significantly with addition of clays. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1684–1691, 2006     

New method for the synthesis of clay/epoxy nanocomposites

A new liquid–liquid method for the synthesis of epoxy nanocomposites was developed. This new method improved the dispersion and exfoliation of the organoclay in the polymer matrix, thus improving the end‐use properties. The microstructure and physical properties of the clay/epoxy nanocomposite synthesized by the new method were studied. Rheological tests of the uncured epoxy–organoclay system demonstrated that this method resulted in a great increase in viscosity, much more than the most commonly used direct‐mixing method. The Krieger–Dougherty model successfully described the dispersion of the clay layers in the uncured epoxy. In the 5 wt % organoclay nanocomposite, compressive tests on the cured samples showed that there was a 45% increase in the maximum strength, a 10% increase in the yield strength, and a 26% increase in the modulus over the pure epoxy–amine cured system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4286–4296, 2006     

Preparation and properties of epoxy nanocomposites. Part 2: The effect of dispersion and intercalation/exfoliation of organoclay on mechanical properties

The effect of the dispersion and intercalation/exfoliation of organoclay on the mechanical properties of epoxy nanocomposites was studied. The epoxy resin was EPON828 and the hardener was Jeffamine D‐230. The organoclay Cloisite 30B was used. Nanocomposites were prepared by different mixing devices that can generate different shear forces, such as a mechanical stirrer, a microfluidizer, and a homogenizer. The results indicate that the modulus increases almost linearly with the clay loading and also is improved with the quality of microdispersion, although the latter plays a less important role. On the other hand, only good dispersion can improve the strength, while poor dispersion results in loss of strength. The strength levels off above 4 wt% organoclay loading. It can be concluded that finer and more uniform dispersion increases the clay surface area available for interaction with the matrix and reduces stress concentration in the large aggregates that initiate the failure under stress. It is also observed that the presence of C30B does not significantly affect the glass transition (T_g) of the epoxy systems regardless of the level of clay dispersion and clay loading. Dynamic mechanic analysis (DMA) shows the positive effect of dispersion and intercalation/exfoliation on the storage modulus of epoxy nanocomposites (ENCs). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Modeling the delamination process during shear premixing of nanoclay/thermoset polymer nanocomposites

As shear premixing is an important process for the dispersion of nanoclays in polymeric resins, this article studies the effect of temperature, duration, speed of premixing, and also the interlamellar spacing of clay platelets on the dispersion of organoclay in epoxy by using a high speed premixing technique which can generate high shear. The quality of dispersion and intercalation/exfoliation of organoclay in epoxy after premixing (before adding hardener) was analyzed by means of X‐ray diffraction (XRD) and rheological measurement. The dispersion and intercalation/exfoliation of organoclay in the epoxy nanocomposites (ENCs) after curing were characterized by TEM. The results illustrate that the intercalation/exfoliation of organoclay in epoxy at the premixing step is very much depending on the premixing parameters. This article also presents a model which takes into account the parameters such as the interlamellar spacing of clay platelets, the viscosity of the epoxy‐clay mixtures, and the velocity of the mixer to explain their effect on the dispersion of clay in epoxy resin. The study focuses on the flow of epoxy clay in the high shear mixer to describe a model for predicting the processing conditions necessary for achieving delamination of the clay layers. Experimental results on the dispersion of clay are also provided to validate the model. The model provides a guide for the premixing parameters necessary to separate the clay layers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Properties of poly(vinyl alcohol)—Bentonite clay nanocomposite films in relation to polymer–clay interactions

This study describes an effective way for the preparation of well‐dispersed, high‐loaded PVA/bentonite nanocomposites with improved properties, based on nanoscale interactions. To this end, a series of Poly(vinyl alcohol)—bentonite clay nanocomposites have been prepared via solvent casting technique and their properties were thoroughly investigated by atomic force microscopy, transmission electron microscopy, X‐Ray diffraction, oxygen and water permeability, water sorption along with mechanical and thermal studies. Microscopic and XRD techniques revealed highly organized regions. Clay content up to 10% led to nanocomposites with high degree of exfoliation. In addition samples with increased filler content (20%) demonstrated also, apart from the delaminated, well‐organized intercalated regions. The nanocomposites exhibited increased mechanical, thermal and gas barrier properties, though they retained their optical clarity. Thus, the Young's modulus of the sample containing 20% clay was increased by 193 times, while the oxygen permeability was decreased about seven times, in regard to the corresponding values of the neat polymer. The obtained results were explored on the basis of nanoscale phenomena and it was concluded that the organized structures and intercalated regions observed on highly loaded samples are attributed to the competitive effect between weaker polymer–polymer interactions in relation to stronger polymer–clay ones. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Self-healing and anticorrosive properties of Ce(III)/Ce(IV) in nanoclay–epoxy coatings

The self-healing and anticorrosion effects of cerium nitrate in epoxy–clay nanocomposite coatings systems were studied. Different amounts of cerium (III) were added to epoxy–montmorillonite clay composites and the nanocomposite coatings were prepared and applied on cold rolled steel panels. Ultrasonication was applied to disperse the nanoclay into the epoxy cerium nitrate composition. Electrochemical impedance spectroscopy (EIS) was used to study the self-healing and anticorrosion behaviors of the coatings. The structure of the dry coating and the protective mechanism of the pigments in the coating were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) analysis and field emission electron microscopy (FESEM). Transmission electron microscopy (TEM) illustrated the separation of clay layers which interacted with the epoxy resin. Electrochemical impedance data indicated that the epoxy cerium (III)–montmorillonite nanocomposite coatings were superior to the epoxy coatings in corrosion protection properties. The self-healing behavior of such coatings was due to the presence of cerium nitrate that could be released at the defects within the coating and hindered the corrosion reactions at the defective sites. It was shown that the best corrosion protection was achieved with nanocomposite coatings containing 4 wt% clay and 2 wt% cerium nitrate.