Iranian Journal of Chemical Engineering (IJChE)

Abstract Polymer nanocomposites reinforced with multi-walled carbon nanotubes (MWCNTs) offer promising mechanical performance; however, predicting their tensile modulus remains challenging due to the complex interplay of multiple factors such as filler content, functionalization, and interphase quality. In this study, a dataset of 229 samples was compiled from the literature, augmented via cubic spline interpolation to 4,933 training points, and analyzed using six machine learning models, including SVR, Random Forest, Gradient Boosting Regressor, XGBoost, KNN, and Artificial Neural Networks (ANNs). The inclusion of the interphase modulus (Ei), calculated via an extended Ji model, proved critical for improving prediction accuracy. Among all models, Gradient Boosting Regressor and XGBoost achieved the best predictive performance (Test R² = 0.9868 and 0.9837, respectively), while ANN demonstrated competitive accuracy (Test R² = 0.9703) but higher sensitivity under cross-validation (Mean CV R² = 0.7486). Feature importance analysis using SHAP further confirmed the significant contribution of Ei to prediction outcomes. Overall, this work demonstrates that incorporating physically-informed features like interphase modulus, combined with robust machine learning pipelines, can substantially enhance the predictive modeling of nanocomposite mechanical properties, providing a valuable tool for material design and optimization.

Abstract Plant fiber composites are currently experiencing strong development, particularly due to the growing interest in them in the automotive industry. These fibers are an excellent alternative to glass fibers from the environmental point of view due to their biodegradability and their much more neutral combustibility in terms of the release of harmful gases or solid residues. However, the incorporation of cellulosic materials into the thermoplastic matrix affects a large number of properties. Many factors, such as the nature and rate of the incorporated filler, can influence the properties of the composites. The present work involves studying the effect of the particle size of a natural fiber on the properties of a polymer matrix. The plant fibers used are DISS fibers ground into a powder with a particle size of less than 63µm. Different formulations based on HDPE/Diss were prepared with different amounts of the filler (10%, 20% and 30%). The HDPE/Diss composites were first processed using a calender, then molded into samples of various shapes with a thickness of 3 mm by compression at 190 °C. These were characterized by various techniques: physical tests, mechanical tests, rheological and morphological tests.

Abstract The goal of this study was to examine the morphology and characteristics of a blend of polylactic acid (PLA) with thermoplastic corn starch (TPS) and polyethylene glycol (PEG-400) using the extrusion process. The blends were evaluated through the tensile and impact strength tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The experimental design method was selected to quantitatively analyze the influence of the content of TPS and concentration of the plasticizer on mechanical properties. Results from the tensile test showed that the addition of PEG-400 decreased tensile strength and elastic modulus, but increased elongation at break and impact strength, significantly. The blend with 20% TPS and 20 phr PEG-400 had the best overall performance in terms of tensile strength, elastic modulus, elongation at break, and impact strength. The SEM analysis indicated increased incompatibility and phase separation in samples with 40% TPS. Additionally, at high concentrations of PEG-400, the excessive plasticizer caused polymer saturation, resulting in unabsorbed plasticizer and phase separation. The findings suggest that the blend with 20% TPS and 20 phr PEG-400 could be suitable for use in eco-friendly applications.

Abstract Polymer chains- tethered membranes exhibited a technic to improve membrane surface, and can be commonly used to change the inherent surface physico-chemical properties of materials. So, the grafting of poly(methyl methacrylate) (PMMA) chains onto poly(vinylidene fluoride) (PVDF) substrate was carried out via surface initiated atom transfer radical polymerization (SI-ATRP) at room temperature. Surface coverage and grafting density were controlled by adjusting the  concentration of the initiator. The attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA) results indicated that the PMMA brush was successfully synthesized on the substrates. The study examined the alterations in the physical characteristics of a the PVDF membrane modified with polymer brushes using the scanning electron microscopy. The results showed that PMMA brushes were attached not only to the outer surface of the membrane but also to the surfaces of its pores. Results from the atomic force microscopy and water contact angle measurements confirmed the homogeneous grafting of PMMA chains onto the substrate.

Abstract The synthesized polystyrene has weaknesses in terms of mechanical, physical and thermal properties which limit the use of this polymer. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of the polymer being prepared from the mixture of several polymers. In this study, different percentages of nanocomposites in different stirring speeds have been added to polystyrene. Different tests have been performed on the prepared polymer and investigating the tests shows that in different stirring speeds the values of the tensile strength and impact resistance of the prepared polymer can be increased while the values of the Vicat Softening Temperature (vicat) and Melt Flow Index (MFI) test numbers remain constant. The obtained results from the laboratory data have been simulated by Artificial Neural Networks (ANNs) in order to predict the results for the points which have not been tested and the simulated results show that the laboratory data covered the simulated data perfectly. The results of tests show that by increasing nanoparticles, the resistance of the polymer against impacts will be increased and in addition, increasing the rate of the stirrer causes all other values of tests to increase.

Abstract In this study, the main purpose has been to investigate the behavior of the nanoparticles with different structures and similar based materials in polymer nanocomposites. To this end, different samples, containing PS as the matrix, and layered graphene oxide (GO) and/or hollow graphene oxide nanoparticles (HGO), were prepared via the melt mixing process and were subjected to heat conduction and tensile tests. To evaluate all features of the interaction between the polymer phase and the nanoparticles, a thermal/mechanical analytical model was proposed and the results were used to simulate the behavior of specific geometrical structures, corresponding to the real samples, under different thermal/mechanical conditions. The results showed good agreement between the obtained experimental data and simulation/analytical model interpretations. In addition, it was found that the HGO nanoparticle had such a good performance in enhancing the thermal and mechanical properties of the nanocomposite, due to its unique structure.

Abstract General Purpose Polystyrene (GPPS) has weak properties and this weakness made the applications of this polymer be limited. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of preparing polymer from the mixture of several polymers. In this research, the polymer blend of GPPS and Acrylonitrile-Butadiene Styrene (ABS) has been investigated. In order to prepare this polymer mixture, GPPS has been considered as the main phase (base polymer) and ABS has been considered as the scattered phase (additive). Firstly, the blended polymers with different weight percentages (0, 0.04, 0.08 and 0.12) of ABS/GPPS in different mixing speeds (30, 40, 50 and 60 rpm) have been prepared and for each mixture, the Melt Flow Index (C), Vicat Softening Temperature, Tensile at Break and impact test have been measured. The laboratory data collected from different tests, has been simulated by the Multi-Layer Perceptron (MLP) method of Artificial Neural Networks (ANN) and the results of the simulated data covered the laboratory data perfectly. The results declare that the presence of ABS in the mixed polymer improved the Tensile strength and thermal properties. In order to reach the highest quality in carried out tests, it is considered to use ABS in a high percentage (0.12) and the maximum possible mixing speed (60 rpm).

Abstract Due to the importance of nanoparticles stability in industrial applications, in this research, stability of laponite nanoparticles dispersions containing different concentrations of sodium sulfonated polyacrylamide (SPA) was investigated in electrolyte media for oil reservoirs applications. In this regard, effect of parameters such as polymer concentration, temperature, and ionic strength were studied via different methods such as Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and zeta potential. In FT-IR spectra of SPA-laponite dispersion, in addition to typical peaks of laponite, there was a weak peak at 1040cm-1 characterizing SPA polymer. The z-average particle sizes of laponite particles increased after 168 h of aging in presence of SPA polymer. Zeta potential measurements showed that, adsorption of anionic groups of polymer on particle surface during the aging process has led to a decrease in zeta potential value (toward more negative values). It was seen that dispersion stability depended on polymer concentration, ionic strength of aqueous media, and temperature. Visual observations showed that the stability of laponite nanoparticles in electrolyte media was improved by increasing the SPA polymer concentration. The rheological studies showed that the viscosity curves of SPA-laponite dispersions were located below those of the corresponding pure SPA polymer solutions. Consequently, particle settling was hindered by increasing the polymeric matrix viscosity. Furthermore, using a power-law equation fitted to the polymer solution viscosity-shear rate data, it was shown that laponite nanoparticles stability in electrolyte media could be improved by decreasing the power-law coefficient.

Abstract The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC plastisol with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength of the joints was determined by single-lap shear test. Moreover, mechanical properties and microstructure of coating were investigated. The addition of 1wt% nano-silica to plastisol dramatically increased the lap shear strength up to 4-fold, which was an outcome of compatibilizing effect of silica. Young's modulus and tensile strength of plasticized PVC were slightly increased by adding nanoparticles, as well. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibited higher inclusion size in the coating having higher silica volume which was attributed to the agglomeration of nanoparticles. In the following, the effect of plasticizer composition on the adhesion strength by replacing some part of dioctyl phthalate (DOP) plasticizer with more polar oil, epoxidized soybean oil (ESO), was examined. Although adding ESO improved the lap shear strength of the neat coating, its effect on the properties of the coatings containing silica was negligible.

Abstract Silver sulfadiazine is used to prevent and treat infections of second- and third-degree burns. It kills a wide variety of bacteria. In this study silver sulfadiazine was used in gelatin based electro-spun nano-fibers with various drug to polymer ratios (0, 5, 10, 15 and 20 %). SEM, EDX and FTIR analysis showed that the continuous, bead-free, fine fibers containing silver sulfadiazine as an antibiotic drug were successfully produced. The release profiles of the loaded drug from the produced nano-fibrous dressings were evaluated by an in vitro elution method. It was observed that the sample with 10wt% of gelatin has had the optimum trend of release. Moreover, antibacterial activity of the dressings was evaluated against the pathogenic micro-organisms S.aureus and E.coli in the nutrient agar solid medium. It was obvious that all the samples had antibacterial activity against these two bacteria. The produced silver sulfadiazine loaded gelatin based electro-spun nano-fibrous dressings have the potential for being used in the wound healing applications.

Abstract This study presents the synthesis of polyvinyl acetate (PVAc) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (PVA) using alkaline alcoholysis. The influence of the molar ratio of hydrolysis catalyst (NaOH) to PVAc and the time and temperature of the saponification reaction on the degree of hydrolysis and molecular weight of the PVA were investigated using response surface methodology. Statistical analysis of the results revealed that the degree of hydrolysis and molecular weight of PVA were strongly dependent on the molar ratio of NaOH/PVAc. It was also found that the second-order interactions between the investigated parameters were not statistically significant. The optimal conditions for synthesizing PVA as a primary suspending agent were obtained as T = 45°C, t = 33 min and NaOH/PVAc (molar ratio) = 0.05. The chemical structures of the PVAc and the optimum PVA were studied by Fourier transform infrared spectroscopy. The distribution of acetate groups in the optimum PVA was determined using 13C nuclear magnetic resonance spectroscopy. It was found that addition of benzene as well as one-step addition of NaOH (when compared with drop-wise addition) result in more blockiness in the acetate group distribution of PVA. The performance of the optimum PVA was also investigated for a typical suspension polymerization of vinyl chloride and the particle morphology of the product was studied using scanning electron microscopy.

Abstract In this study, in-situ bulk polymerization was investigated for obtaining flame retardant polystyrene (PS). The halogenated and phosphoric compounds were used as flame retardant additives and Perkadox 30 was used as a synergist. The flammability of the PS was evaluated by thermogravimetric analyzer (TGA), limiting oxygen index (LOI) and UL-94 tests. The results show that polymerization process for production of flame retardant polystyrene needs lower amount of flame retardant additives compare with the process for production of flame retardant composites. Furthermore, using Perkadox 30 as a synergist lowers the loading of flame retardant additives. LOI tests show that flame retardant polystyrene synthesized by adding at least 0.35 % (w/w) hexabromocyclododecane (HBCD) during polymerization. TGA analysis confirms that with addition of HBCD the degradation temperature decreases and weight loss occurs quickly. The degradation tempresure of the sample consist of 0.8 % (w/w) HBCD was lower than the sample consist of 0.35 % (w/w) HBCD and 0.45 % (w/w) triphenylphosphate (TPP). The pure polystyrene didn’t pass the UL-94 test because of inflammability and greater dripping. For samples with HBCD, shorter time needed to quench the flame and these samples passed the UL-94 test. On the other hand, greater dripping of polymer melt led to transmission of UL-94 rate from V0 to V2. It is also observed that flaming rate for samples with TPP was very low and dripping didn’t occur.

Abstract In this study, the relation between the permeation properties and structural characteristics of thermoplastic polyurethane based on polycaprolactone diol, TPU(PCL), and polycaprolactone (PCL) blends is investigated. for the purpsoes of this study, PU, PCL, and TPU/PCL blends containing 20 wt.% and 40 wt.% PCL were prepared via a solution blending method. The miscibility and good distribution of PCL in the soft segment of PU were represented by the reduced intensity of the band attributed to the NH band at 3400 cm-1 in the Fourier transform infrared (FTIR) spectra. X-ray diffratcion (XRD) results indicated that the amorphous structure of TPU changed to a crystalline one when PCL was added. These results were further confirmed by FTIR and differential scanning calorimetry (DSC) analyses. The permeability of CO2, O2, N2, and CH4 gases at different feed pressures ranging from 12 to 16 bar were determined. A reduction in gas permeability due to the increase in PCL content was observed in the blends. However, gas selectivity did not change with addition of PCL.

Abstract Suspension polymerization process is commonly used to produce expandable polystyrene. In the conventional method for producing this polymer, two different initiators are added to the process at two different temperature levels. In the industrial scale, this process is time consuming and difficult to control. A new method (Multi-Stage Initiator Dosing, MID) is proposed, in which, the initiator is dosed into the reactor. In the laboratory and bench scale tests of this new method results in better control of the process, shorter reaction times and better quality of the product. Optimum temperature and dosing intervals are determined. The properties of the prepared samples by MID and conventional methods are compared with each other. According to the results obtained with the implementation of new methods for the production of expandable polystyrene reduce time process and consuming amount of initiator and because the initiator dosing in several stages, the suspension control would be easier. Also absorption rate was higher pentane and grain size better than the conventional.

Abstract Poly (vinyl alcohol) (PVA) nanofibers were prepared via electrospinning of concentrated PVA solutions. The nanofibers were crosslinked to enhance their resistance against the moisture. The chemical crosslinking of the nanofibers was carried out using glutaraldehyde as crosslinking agent in the presence of hydrochloride acid. The chemical structure, water solubility, and morphology of the electrospun PVA nanofibers were characterized by Fourier transform infrared (FTIR)
spectrometer,water durability test, and scanning electron microscope (SEM), respectively. In addition, the crosslinked nanofibers were coated by copper nanoparticles (CNPs) using electrospraying technique. For this purpose, colloidal CNPs were synthesized through the chemical reduction of copper ions in the presence of different stabilizers, i.e. poly (vinyl alcohol) and ethylene glycol (EG), in an aqueous media. The effect of the stabilizer concentration (0.001 and 0.005 M) and reduction temperature (25 and 70°C) were investigated on the CNP dispersion in the media using UV-visible spectroscopy. Furthermore, the dispersion of the CNPs on the PVA nanofibers was studied by means of SEM. The SEM micrographs showed that the nanofiber scould properly imprison the CNPs. Successful the proposed approach would be exploited to prepare polymer nanofibers incorporating metal nanoparticles which might have interesting properties such as antibacterial activity.

Abstract In this study, polysulfone (PSF) flat membrane prepared via non-solvent phase inversion method was employed in gas-liquid membrane contactor module to absorb CO2. Two polymer concentrations of 16 wt% and 18 wt% were used in the dope solution of fabricated membranes. The membranes were characterized in terms of morphological structure and contact angle. Scanning electron microscopy (SEM) analysis demonstrated that PSF membrane with polymer concentration of 16 wt% in the dope solution has a porous layer with a combination of finger-like, sponge-like and macrovoid structures, but the other membrane has a sponge-like structure. Also, characterization results through atomic force microscopy (AFM) and contact angle measurement demonstrated that the porosity, surface roughness and hydrophobicity of the PSF membranes decreased with an increase in polymer concentration. Evaluationof mass transfer resistance displayed that the resistance of the PSF membrane with polymer concentration of 18wt% in the dope solution is higher than that of the other membrane. In addition, decreasing the polymer concentration significantly improved CO2 absorption flux. At the absorbent flow rate of 9.7 ml/min, the CO 2 absorption flux of PSF membrane with 16 wt% polymer concentration was 2.17 times higher than the absorption flux of the PSF with 18 wt% polymer concentration.

Abstract Due to wide application of styrene for production of different materials, it is considered as an important product in industry. Therefore, optimizing styrene production conditions is of great importance in petrochemical industry. In this paper, styrene production reactors of Tabriz Petrochemical Complex are modeled using Artificial Neural Network (ANN) model and Adaptive Neuro Fuzzy Inference System (ANFIS). Comparison of two models revealed that the neural networks are more reliable. The process of design and evaluation of models are carried out using industrial data which show credibility of designed models. The neural networks are designed to predict the styrene output from reactors as a function of effective input parameters on the styrene production. Predictions of designed neural networks were used to study the effect of each variable, such as oxygen flow rate and steam oil ratio, on the amount of styrene produced. Also, the optimal values of effective variables for maximum production of styrene were obtained. Furthermore, in order to obtain accurate results, catalyst deactivation of styrene reactors has been modeled using Fuzzy Inference System. As a result, catalyst activity as a function of time is obtained.

Abstract The ultra-high molecular weight polyethylene (UHMWPE) was prepared using titanium tetrachloride (TiCl4) supported by MgCl2 (ethoxide type), accompanied by triisobutylaluminium (TIBA) as co-catalyst. These all constituted the Ziegler–Natta
catalytic system. MgCl2 is one of the best supports for Ziegler-Natta catalyst in order to increase its yield.In the present study, the process variables were investigated through response surface methodology (RSM) to optimize the productivity of the catalyst and also the molecular weight of the polymer. Taking this into consideration a three-level Box-Behnken design for three factors with temperature (X1), monomer pressure (X 2), and [Al]/[Ti] molar ratio (X 3) as the independent variables were selected. Different molar ratio of [Al]/[Ti] is achieved by changing the amount of the co-catalyst.The dependent variables were productivity and molecular weights of the prepared polymers. Specifically, using these three parameters at three levels including 50, 60, and 70°C for temperature; 4, 6, and 8 bar for pressure; and 150, 250, and 350 for [Al]/[Ti] molar ratio. The RSM yielded optimum reaction conditions equal to: temperature of 55°C, pressure of 8 bar, and [Al]/[Ti] molar ratio of 230. Under these optimum conditions, the productivity and molecular weight were 2628 g PE/mmolTi.h and 5.09×10 6 g/mol, respectively.

Abstract This research work focuses on the performance optimization of composites containing both micron and nano size TiO 2 particles separately in various concentrations and to understand the role of each on the thermal stability and moduli of the composites. Thermal stability of the particle-reinforced composites increased on increasing the concentration of TiO 2, both in nano and micron filled cases, except for the 2.5 wt% nano-filled composite. Storage modulus (E') increased on adding micron-TiO2 to the epoxy hardener resin system from 1 - 2.5 - 5 wt% respectively and decreased dramatically on further increasing the micron TiO 2 content to 7.5 and 10 wt% respectively. Nano TiO 2 particle-reinforced composites showed an increasing trend of storage modulus for 2.5 - 5 - 7.5 wt% TiO 2 filled composites with respect to the neat
resin system. Presence of both micron and nano TiO2 particles increased the T g of the composites. Also, the effect of sonication on the modulus and Tg is discussed. As a whole, composites in which the TiO 2 particles were dispersed through the resin matrix by glass rod revealed better results (higher storage moduli and T g) than those mixed by sonication, due to high viscosity of the epoxy resin used.

Abstract Turbulent flow field in a 200 m3 industrial suspension polymerization reactor, which is a baffled agitated vessel, was simulated using CFD. Multi-reference frame (MRF) methods and k-Â turbulence model were used to solve turbulent flow equations. It was found that turbulent flow field in reactor is non-homogenous. This non-homogeneity is especially common among three compartments of a reactor based on turbulent kinetic energy (TKE) dissipation rate. A compartment around the impeller with very high rate of TKE dissipation (impeller zone), a compartment around the baffles with a relatively high rate of TKE dissipation (baffle zone) and a relatively big compartment in bulk of flow with low TKE dissipation rate (circulation flow). Therefore a three-compartment model was used to explain the non-homogeneity of turbulent flow field. The parameters of this model are compartment volume ratios (Ïi and Ïb), compartment energy
dissipation ratios (Îb and Îi) and exchange flow rates (Qi and Qb), which were obtained from simulations for different agitation rates.

Abstract Creep and stress relaxation of a polypropylene (PP)-based copolymer, a metallocene-prepared linear low density polyethylene (m-LLDPE) and their m-LLDPE/PP blends have been investigated. Struik and Nutting relationships were used for fitting the data obtained from the creep experiments. A relatively good agreement was found between the Struik model and the experimental data obtained from PP and the 50/50 blend, however, the results showed that the validity of the model is less for the m-LLDPE itself. A good correlation was also found for the Nutting relationship and the experimental data. Maxwell and Kohlrausch-Williams-Watts (KWW) equations were used to fit the data obtained from stress relaxation experiments. The results indicated that while the Maxwell model was not good enough to predict the stress relaxation time, KWW model could fit the data much better. Analysis of the data with KWW equation revealed that the relaxation time increased with m-LLDPE content, but not significantly. However, the factor that describes the width of relaxation time distribution reduced with m-LLDPE, showing that m-LLDPE had the broadest relaxation time distribution compared to that of PP and the blends.

Abstract Polyurea microcapsules containing an active agent, i.e. ethion as pesticide, have been prepared by interfacial polymerization between 2, 4-toluene diisocyanate (TDI) and diethylenetriamine (DETA) in an oil-in-water (O/W) emulsion system. The effects of the nature of the emulsifier, the monomer weight ratio, and a novel promoter, i.e. potassium phthalimide-N-oxyl (PPINO), on the morphology, microstructure, and thermal stability of the microcapsules have been investigated. PPINO was used as a water-soluble promoter capable of dimerizing and trimerizing the isocyanate reactant
in the interfacial polymerization. The transmission electron microscopy (TEM) micrographs showed that the addition of the promoter had no significant effect on the microcapsule shell thickness. Increasing the amount of PPINO caused the degree of crystallinity of the polymer shell to decrease considerably. In addition, increasing the amount of promoter up to 2 wt% caused the thermal stability of the microcapsules to decrease, while using promoter beyond this level resulted in higher thermal stability.

Abstract The effect of cobalt naphthenate and 2-benzoylbenzoic acid on UV-photooxidative degradation of low density polyethylene have been studied. Sheets of these samples were prepared from polyethylene and different concentrations of cobalt naphthenate and 2-benzoylbenzoic acid then these samples were UV-irradiated. Changes in the carbonyl index, tensile strength, elongation at break, crystallinity and density were measured to monitor the degradation. The measurements were done before and after UV-irradiation at every 30-day interval for 90 days. The results show that the UV-irradiation affects the rate of degradation of LDPE with increasing the concentration of the cobalt naphthenate and 2-benzoylbenzoic acid. The increasing rate of degradation is more obvious for the increased concentration of cobalt naphthenate and also the time of irradiation, but the rate of degradation is decreased by incorporation of 2-benzoylbenzoic acid.

Abstract In the present work, a population balance model is used to predict dynamic evolution of droplet/particle size distribution in non-reactive liquid-liquid dispersions and reactive liquid (solid)-liquid suspension polymerization systems. The effect of dispersed phase hold-up and agitation rate on droplet/particle size and droplet/particle size distribution are investigated. The cell average technique is applied for solving the population balance equation. Predictive capability of the presented model is demonstrated by comparison of model predictions with experimental data regarding the average mean diameter for non-reactive liquid-liquid dispersions and the free-radical suspension polymerization of styrene.

Abstract Composites of polyaniline with calcium carbonate particles (PANI/CaCO3) with different CaCO3 content (0-40 %w/w) were prepared. Two different methods of in situ polymerization and solution mixing were used for PANI/CaCO3 composite preparation. The composite was characterized using FT-IR, SEM, electrical conductivity measurement and cyclic voltammetry techniques. The incorporation of CaCO3 particles in polyaniline matrix in both methods of composite preparation was confirmed by FTIR results. Electrical conductivity measurements showed that the conductivity of the composite decreases by increasing the CaCO3 loading in polyaniline. Also, the anticorrosive property of the PANI/CaCO3 composite coating on iron samples was investigated in various corrosive environments. According to the results, the corrosion rate or corrosion current of PANI/CaCO3 composite coated iron coupons was much lower (96.75%) than polyaniline coated samples. Also, results showed that the corrosion current of composite coated samples varies with the variation of the CaCO3 content in composite coating, and the optimum CaCO3 content of composite coating to achieve the best anticorrosive performance on iron is 10 %w/w.