Hassan Ebadi Dehaghani - Academia.edu (original) (raw)

Papers by Hassan Ebadi Dehaghani

Research paper thumbnail of Selective Co2/Ch4 Separation by Nanocomposite Membranes Based Poly Ether Block Amide / Polyvinyl Alcohol and Nano Mgo: Design of Experiments and Molecular Dynamics Simulation Study

Research paper thumbnail of Caracterizacion y tratamientos termicos de recubrimientos metalicos de niquel electroless

Research paper thumbnail of Controlled Release of Novel Volatile Corrosion Inhibitor (VCI) Nanoparticles Incorporated in Low Density Polyethylene (LDPE) Films for Steel Coverings: Correlation of Experimental Results with Molecular Dynamics Simulation

The compositions of 10 different VCI compounds were optimized. Low density polyethylene (LDPE), E... more The compositions of 10 different VCI compounds were optimized. Low density polyethylene (LDPE), ECA-5 copolymer (poly(ethylene-co-methyl acrylate) as an ethylene based coupling agent) and the prepared VCI compound, so called BFA-200, were processed in a twin screw extruder followed by a film casting method to make films. The 80/20 LDPE/ECA-5 composition was determined as the optimized VCI unfilled blend having the maximum mechanical properties for the film processing; the BFA-200 VCI nanoparticles (5, 10 and 15%) were added to this composition. Measurement of the controlled release of the VCI within the LDPE/ECA-5/BFA-200 80/20/15 sample was carried out using thermo-gravimetric analysis (TGA). The TGA method was also used for determination of the VCI content after periods of 3, 6 and 12 months in polyethylene bags stored at ambient conditions. There was a significant difference in the release of VCI agent for the blends as compared to that of VCI incorporated in only LDPE. The prese...

Research paper thumbnail of Design of Experiments for the Effect of pH, Storage Time and Zinc Oxide Content on the Antibacterial Properties of Low-Density Polyethylene (LDPE)/Zinc Oxide Nanocomposites

Journal of Macromolecular Science, Part B, 2020

Abstract The use of nanotechnology-based, active antibacterial materials in food packaging is of ... more Abstract The use of nanotechnology-based, active antibacterial materials in food packaging is of great importance for users health. Related to such potential use nanocomposite films containing 2.5%, 5%, 7.5% or 10% zinc oxide contents were melt mixed followed by blown film extrusion. Mechanical tests showed the best improvement in tensile strength and modulus for 5% loading. The effects of three factors, zinc oxide (ZnO) content, storage time and pH, on the antibacterial properties were investigated using response surface methodology (RSM). According to the results the analysis of variance by the RSM for the antibacterial properties of the low-density polyethylene ZnO nanocomposites followed a Quadratic model. The results showed that the maximum efficiency could be achieved at pH = 4.48. In addition, RSM showed the maximum antibacterial properties would be obtained for a reaction time of 5.5 days and zinc oxide content of 9.45%, which was near to the experimental value of 10%.

Research paper thumbnail of On Localization of Clay Nanoparticles in Polypropylene/poly(Lactic Acid) Blend Nanocomposites: Correlation with Mechanical Properties

Journal of Macromolecular Science, Part B, 2016

ABSTRACT Two polypropylene (PP)/polylactide (PLA)/clay ternary nanocomposite systems, i.e. PP-ric... more ABSTRACT Two polypropylene (PP)/polylactide (PLA)/clay ternary nanocomposite systems, i.e. PP-rich and PLA-rich ones, each containing various amounts of one of two types of clay, were prepared by one step melt compounding in a twin screw extruder. The microstructures of the developed systems were correlated with tensile and impact properties. A theoretical calculation using wetting coefficients was used for predicting the clay nanoparticles localization in the blends. The nanoparticles were almost completely located within the PLA phase in both the PP-rich and PLA-rich systems, in good agreement with the predictions. Addition of a compatibilizer led to localization of the nanoparticles at the interfaces of the blends. From the wide angle X-ray scattering (WAXS) spectra it was concluded that the incorporation of clay led to intercalated structures in the both systems. The increase in impact toughness of the compatibilized blend nanocomposites, with respect to the uncompatibilized ones, was attributed to the weakened interfacial debonding in the presence of the interfacial-localized nanoparticles.

Research paper thumbnail of Biodegradation and hydrolysis studies on polypropylene/polylactide/organo-clay nanocomposites

Polymer Bulletin, 2016

Polypropylene/Poly(lactic acid) (PP/PLA) nanocomposites based on organically modified montmorillo... more Polypropylene/Poly(lactic acid) (PP/PLA) nanocomposites based on organically modified montmorillonites at 5 wt% loading were prepared by melt blending using a co-rotating twin-screw extruder. Degradation of compression-molded thin films of the nanocomposites was investigated in compost by infrared spectroscopy (IR), optical microscopy (OM) and weight loss measurements. The differential scanning calorimetry (DSC) was found to be a suitable method for study of the effect of hydrolysis of the samples in acidic or basic solutions. The IR and OM studies of the samples buried under compost for 12 months confirmed the biodegradation phenomena. Moreover, a good correlation was established between the degrees of crystallinity and hydrolysis extent. These studies showed that the addition of nanoclays can increase the PLA degradation. Microbial degradation by Aspergillus niger fungi incubated using a nutrient media in an incubator for 1 month showed a weight reduction of 0.3–0.5 % during such a short period of microbial degradation.

Research paper thumbnail of The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

Journal of Macromolecular Science, Part B, 2014

Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe2O3 (ferr... more Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe2O3 (ferrite) nanoparticles (IO) was investigated. Three nanocomposites, filled with 2.5, 5, and 10 wt.% of IO nanoparticles, were processed in the melt state at 260°C. A nanocomposite containing 5 wt% of nano-silica was also prepared similarly as the blank sample. Dynamic mechanical thermal properties of the nanocomposites showed that, while the introduction of SiO2 nanoparticles increased the glass transition temperature (Tg) of PET, incorporation of IO nanoparticles led to a decrease in Tg. There was an increase in rheological storage modulus (G′) of PET with incorporation of SiO2 nanoparticles in the low-frequency region. Conversely, the incorporation of IO nanoparticles led to a decrease in G′ in this frequency region. The decrease of G′ was attributed to hydrolysis of PET due to the presence of impurities in the IO. The zero-shear rate viscosity (η0) increased with incorporation of SiO2 nanoparticles. Conversely, this value decreased with incorporation of IO nanoparticles. While rheological studies showed a significant decrease in molecular weight of the PET due to hydrolysis, the IR spectroscopy did not have sufficient ability for assessment of the hydrolysis phenomenon. However, the viscosity-average molecular weight () measurements showed that the molecular weight decrease found via rheological studies was in good accordance with the values.

Research paper thumbnail of Preparation and Characterization of Functional Poly(ethylene glycol) Surfaces for the Use of Antibody Microarrays

Analytical Chemistry, 2007

ABSTRACT

Research paper thumbnail of Microstructure and Properties of Polypropylene/Clay Nanocomposites

Journal of Macromolecular Science, Part B, 2016

ABSTRACT Nanocomposites of polypropylene (PP) containing various contents of Cloisite 15A nanocla... more ABSTRACT Nanocomposites of polypropylene (PP) containing various contents of Cloisite 15A nanoclay particles were prepared by one-step melt compounding in a twin screw extruder. Tensile and impact properties of the nanocomposite systems were investigated and correlated with their microstructures. The tensile modulus increased with an increase in Cloisite 15A content but the tensile strength, elongation at break, and impact strength were decreased. WAXS and TEM studies showed almost exfoliated structures. There was a decrease in permeability values with an increase in nanoclay content up to 5 wt. %. Exceeding this content of nanoclay had no significant effect on permeation due to the aggregation phenomenon at high concentrations of the nanoparticles. Most of the examined micromechanical models for prediction of the tensile modulus of the nanocomposite were successful despite being based on fiber-shaped fillers. An exfoliated structure of clay within the nanocomposite was assumed for the modeling using a molecular dynamics simulations approach, employing Dreiding, Forcite, and COMPASS force fields, in order to investigate the best one for a successful estimation of elastic modulus. Relative to the experimental modulus values of the nanocomposites, which were around 1100–1200 MPa, the COMPASS force field had the best correlation with the values with a slight departure of about 10%.

Research paper thumbnail of Chemical Modification of Polypropylene by Maleic Anhydride: Melt Grafting, Characterization and Mechanism

International Journal of Chemical Engineering and Applications, 2014

Polypropylene (PP) was functionalized with maleic anhydride (MAH) in the presence of dicumyl pero... more Polypropylene (PP) was functionalized with maleic anhydride (MAH) in the presence of dicumyl peroxide (DCP) via melt grafting in a batch mixer, where the maleic anhydride and peroxide concentrations were varied. The effect of concentration of monomer and initiator on the degree of functionalization and properties of the products was investigated by FT-IR spectroscopy, contact angle measurement, thermal analysis and titration. It was found that the degree of functionalization depends on the initial concentration of monomer and initiator that used in reaction. Finally a mechanism of melt grafting MAH onto PP proposed on the basis of our experimental results and other experimental finding published in the literature.

Research paper thumbnail of 23 Thermal Conductivity of Nanoparticles Filled Polymers

Thermal conductivity of polymers is an important thermal property for both polymer applications a... more Thermal conductivity of polymers is an important thermal property for both polymer applications and processing. Polymers typically have intrinsic thermal conductivity much lower than those for metals or ceramic materials, and therefore are good thermal insulators. Further enhancement of this thermal insulating quality can be achieved by foaming polymers. In other applications which require higher thermal conductivity, such as in electronic packaging and encapsulations, satellite devices, and in areas where good heat dissipation, low thermal expansion and light weight are needed, polymers reinforced with fillers, organic or inorganic, are becoming more and more common in producing advanced polymer composites for these applications (Hodgin & Estes, 1999; Tavman, 2004; Lee & Eun, 2004; Liu & Mather, 2004; Ishida & Heights, 1999; Frank & Phillip, 2002; Hermansen, 2001; Ishida, 2000). Most polymeric materials are processed and fabricated at elevated temperatures, often above their meltin...

Research paper thumbnail of Assessment of Compatibility in Polypropylene/Poly(lactic acid)/Ethylene Vinyl Alcohol Ternary Blends: Relating Experiments and Molecular Dynamics Simulation Results

Journal of Macromolecular Science, Part B

ABSTRACT Two systems of polypropylene (PP), poly(lactic acid) (PLA) and ethylene vinyl alcohol co... more ABSTRACT Two systems of polypropylene (PP), poly(lactic acid) (PLA) and ethylene vinyl alcohol copolymer (EVOH) ternary blends having different compositions were extruded in a co-rotating twin screw extruder. The first system was PP/PLA (75/25) with various EVOH contents, the second one was PP/EVOH (75/25) having various PLA contents. The effects of composition on the morphology and the tensile and impact properties of the blends were investigated. There were increases in the tensile modulus and tensile strength with an increase in the EVOH and PLA contents in the first and second systems, respectively. A molecular dynamics (MD) simulation was used to investigate the compatibility between the components. Prediction of the miscibility of the blends was carried out by determining the interaction parameters (χ), mixing energies (ΔHmix), phase diagrams and Gibbs free energies. The MD simulation showed a UCST behavior for the components. Moreover, the simulation results showed a compatibilizer effect for the EVOH component. The experimental values of the dynamic mechanical thermal analysis (DMTA) and mechanical properties were correlated to the MD results. There was a good correlation between the MD and DMTA results. The modulus values using the parallel and Davis models were near to the experimental ones. A good fitting to the mixture law with addition of EVOH confirmed a good compatibilzing effect of it between the PP and PLA components.

Research paper thumbnail of Comparing the Effect of Micro- and Nano-Scale Silica on the Rheological, Dynamic Mechanical Properties and Flame Resistance of Nylon 6,6

Journal of Macromolecular Science, Part B, 2014

Nylon 6,6 micro- and nano-silica composites were prepared by melt processing using a twin-screw e... more Nylon 6,6 micro- and nano-silica composites were prepared by melt processing using a twin-screw extruder. Three nanocomposites containing 4, 8, and 12 wt.% of nanosilica were prepared. In order to compare the effect of size, a microcomposite containing 4 wt.% of micron-size silica was also prepared. The effects of particle type (micro- and nano-size) on the dynamic thermomechanical and rheological properties, morphology, and flame resistance of the composites were examined. The dynamic thermomechanical properties (DMTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic rheometry, thermogravimetry analysis (TGA), and limiting oxygen index (LOI) data are reported. The particles were observed to be dispersed uniformly, but with a different level of coalescence, by means of SEM and TEM. The DMTA results showed that the damping factor peak positions of the nanocomposites at low content of nanofiller shifted more to higher temperature compared to those of nanocomposites containing high concentrations of nanofiller. Dynamic rheometry, using a parallel plate rheometer, showed that the rheological moduli of the nanocomposites increased with increase in nanofiller concentration; however, this increase was greater in the high-frequency region. These results showed that increasing the concentration of nanofiller, and the consequent coalescence effect within the nanocomposites, led to rheological moduli values similar to those of the microcomposite. The TGA and LOI results of the microcomposite and nanocomposite containing 4wt.% of nanosilica showed that nanosilica had a more significant effect to enhance the heat and flame resistance of nylon 6,6 compared to that of micron-sized silica.

Research paper thumbnail of Preparation and characterization of sodium alginate–PVA polymeric scaffolds by electrospinning method for skin tissue engineering applications

RSC Advances

The main aim of this study was to improve the spinnability of SA by adding PVA. The main paramete... more The main aim of this study was to improve the spinnability of SA by adding PVA. The main parameters in producing nanofiber from the optimized SA:PVA ratio, including voltage, flow rate, and working space, were also optimized.

Research paper thumbnail of Temperature dependency of gas barrier properties of biodegradable PP/PLA/nanoclay films: Experimental analyses with a molecular dynamics simulation approach

Journal of Applied Polymer Science

Research paper thumbnail of Non-isothermal crystallization and oxygen permeability of PP/PLA/EVOH ternary blends

Journal of Thermal Analysis and Calorimetry

Research paper thumbnail of A combined experimental and theoretical approach to quantitative assessment of microstructure in PLA/PP/Organo-Clay nanocomposites; wide-angle x-ray scattering and rheological analysis

Composites Part B: Engineering

Research paper thumbnail of Diffusion of 1,2,3-Benzotriazole as a Volatile Corrosion Inhibitor through Common Polymer Films Using the Molecular Dynamics Simulation Method

Journal of Macromolecular Science, Part B

Research paper thumbnail of Evaluation of mixing efficiency in elaborating of chitosan/cellulose nanocomposite via statistical analyses

International Journal of Biological Macromolecules, 2016

Research paper thumbnail of On O2 gas permeability of PP/PLA/clay nanocomposites: A molecular dynamic simulation approach

Polymer Testing, 2015

ABSTRACT Polypropylene/poly(lactic acid) (PP/PLA) blends were prepared by reactive blending in a ... more ABSTRACT Polypropylene/poly(lactic acid) (PP/PLA) blends were prepared by reactive blending in a co-rotating twin-screw extruder. Effect of blend composition on oxygen permeability through compression molded films was investigated and correlated to the microstructure. Two blends, PP-rich (75/25) and PLA-rich (25/75), were selected in order to consider the effect of incorporation of clay and compatibilization on the permeability. The PP-rich blends had greater oxygen barrier properties compared to those of PLA-rich blends. Several proposed models of permeability for blends and nanocomposites were examined. These models failed to predict the permeability values, especially for PLA-rich blends. The failure was attributed to the immiscibility issue leading to appearance of microvoids at the interface. Molecular dynamics simulations were performed by employing the COMPASS force field to estimate the diffusivity of oxygen gas through pure components, PP-rich and PLA-rich systems. The simulated results were in good agreement with the available experimental data.

Research paper thumbnail of Selective Co2/Ch4 Separation by Nanocomposite Membranes Based Poly Ether Block Amide / Polyvinyl Alcohol and Nano Mgo: Design of Experiments and Molecular Dynamics Simulation Study

Research paper thumbnail of Caracterizacion y tratamientos termicos de recubrimientos metalicos de niquel electroless

Research paper thumbnail of Controlled Release of Novel Volatile Corrosion Inhibitor (VCI) Nanoparticles Incorporated in Low Density Polyethylene (LDPE) Films for Steel Coverings: Correlation of Experimental Results with Molecular Dynamics Simulation

The compositions of 10 different VCI compounds were optimized. Low density polyethylene (LDPE), E... more The compositions of 10 different VCI compounds were optimized. Low density polyethylene (LDPE), ECA-5 copolymer (poly(ethylene-co-methyl acrylate) as an ethylene based coupling agent) and the prepared VCI compound, so called BFA-200, were processed in a twin screw extruder followed by a film casting method to make films. The 80/20 LDPE/ECA-5 composition was determined as the optimized VCI unfilled blend having the maximum mechanical properties for the film processing; the BFA-200 VCI nanoparticles (5, 10 and 15%) were added to this composition. Measurement of the controlled release of the VCI within the LDPE/ECA-5/BFA-200 80/20/15 sample was carried out using thermo-gravimetric analysis (TGA). The TGA method was also used for determination of the VCI content after periods of 3, 6 and 12 months in polyethylene bags stored at ambient conditions. There was a significant difference in the release of VCI agent for the blends as compared to that of VCI incorporated in only LDPE. The prese...

Research paper thumbnail of Design of Experiments for the Effect of pH, Storage Time and Zinc Oxide Content on the Antibacterial Properties of Low-Density Polyethylene (LDPE)/Zinc Oxide Nanocomposites

Journal of Macromolecular Science, Part B, 2020

Abstract The use of nanotechnology-based, active antibacterial materials in food packaging is of ... more Abstract The use of nanotechnology-based, active antibacterial materials in food packaging is of great importance for users health. Related to such potential use nanocomposite films containing 2.5%, 5%, 7.5% or 10% zinc oxide contents were melt mixed followed by blown film extrusion. Mechanical tests showed the best improvement in tensile strength and modulus for 5% loading. The effects of three factors, zinc oxide (ZnO) content, storage time and pH, on the antibacterial properties were investigated using response surface methodology (RSM). According to the results the analysis of variance by the RSM for the antibacterial properties of the low-density polyethylene ZnO nanocomposites followed a Quadratic model. The results showed that the maximum efficiency could be achieved at pH = 4.48. In addition, RSM showed the maximum antibacterial properties would be obtained for a reaction time of 5.5 days and zinc oxide content of 9.45%, which was near to the experimental value of 10%.

Research paper thumbnail of On Localization of Clay Nanoparticles in Polypropylene/poly(Lactic Acid) Blend Nanocomposites: Correlation with Mechanical Properties

Journal of Macromolecular Science, Part B, 2016

ABSTRACT Two polypropylene (PP)/polylactide (PLA)/clay ternary nanocomposite systems, i.e. PP-ric... more ABSTRACT Two polypropylene (PP)/polylactide (PLA)/clay ternary nanocomposite systems, i.e. PP-rich and PLA-rich ones, each containing various amounts of one of two types of clay, were prepared by one step melt compounding in a twin screw extruder. The microstructures of the developed systems were correlated with tensile and impact properties. A theoretical calculation using wetting coefficients was used for predicting the clay nanoparticles localization in the blends. The nanoparticles were almost completely located within the PLA phase in both the PP-rich and PLA-rich systems, in good agreement with the predictions. Addition of a compatibilizer led to localization of the nanoparticles at the interfaces of the blends. From the wide angle X-ray scattering (WAXS) spectra it was concluded that the incorporation of clay led to intercalated structures in the both systems. The increase in impact toughness of the compatibilized blend nanocomposites, with respect to the uncompatibilized ones, was attributed to the weakened interfacial debonding in the presence of the interfacial-localized nanoparticles.

Research paper thumbnail of Biodegradation and hydrolysis studies on polypropylene/polylactide/organo-clay nanocomposites

Polymer Bulletin, 2016

Polypropylene/Poly(lactic acid) (PP/PLA) nanocomposites based on organically modified montmorillo... more Polypropylene/Poly(lactic acid) (PP/PLA) nanocomposites based on organically modified montmorillonites at 5 wt% loading were prepared by melt blending using a co-rotating twin-screw extruder. Degradation of compression-molded thin films of the nanocomposites was investigated in compost by infrared spectroscopy (IR), optical microscopy (OM) and weight loss measurements. The differential scanning calorimetry (DSC) was found to be a suitable method for study of the effect of hydrolysis of the samples in acidic or basic solutions. The IR and OM studies of the samples buried under compost for 12 months confirmed the biodegradation phenomena. Moreover, a good correlation was established between the degrees of crystallinity and hydrolysis extent. These studies showed that the addition of nanoclays can increase the PLA degradation. Microbial degradation by Aspergillus niger fungi incubated using a nutrient media in an incubator for 1 month showed a weight reduction of 0.3–0.5 % during such a short period of microbial degradation.

Research paper thumbnail of The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

Journal of Macromolecular Science, Part B, 2014

Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe2O3 (ferr... more Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe2O3 (ferrite) nanoparticles (IO) was investigated. Three nanocomposites, filled with 2.5, 5, and 10 wt.% of IO nanoparticles, were processed in the melt state at 260°C. A nanocomposite containing 5 wt% of nano-silica was also prepared similarly as the blank sample. Dynamic mechanical thermal properties of the nanocomposites showed that, while the introduction of SiO2 nanoparticles increased the glass transition temperature (Tg) of PET, incorporation of IO nanoparticles led to a decrease in Tg. There was an increase in rheological storage modulus (G′) of PET with incorporation of SiO2 nanoparticles in the low-frequency region. Conversely, the incorporation of IO nanoparticles led to a decrease in G′ in this frequency region. The decrease of G′ was attributed to hydrolysis of PET due to the presence of impurities in the IO. The zero-shear rate viscosity (η0) increased with incorporation of SiO2 nanoparticles. Conversely, this value decreased with incorporation of IO nanoparticles. While rheological studies showed a significant decrease in molecular weight of the PET due to hydrolysis, the IR spectroscopy did not have sufficient ability for assessment of the hydrolysis phenomenon. However, the viscosity-average molecular weight () measurements showed that the molecular weight decrease found via rheological studies was in good accordance with the values.

Research paper thumbnail of Preparation and Characterization of Functional Poly(ethylene glycol) Surfaces for the Use of Antibody Microarrays

Analytical Chemistry, 2007

ABSTRACT

Research paper thumbnail of Microstructure and Properties of Polypropylene/Clay Nanocomposites

Journal of Macromolecular Science, Part B, 2016

ABSTRACT Nanocomposites of polypropylene (PP) containing various contents of Cloisite 15A nanocla... more ABSTRACT Nanocomposites of polypropylene (PP) containing various contents of Cloisite 15A nanoclay particles were prepared by one-step melt compounding in a twin screw extruder. Tensile and impact properties of the nanocomposite systems were investigated and correlated with their microstructures. The tensile modulus increased with an increase in Cloisite 15A content but the tensile strength, elongation at break, and impact strength were decreased. WAXS and TEM studies showed almost exfoliated structures. There was a decrease in permeability values with an increase in nanoclay content up to 5 wt. %. Exceeding this content of nanoclay had no significant effect on permeation due to the aggregation phenomenon at high concentrations of the nanoparticles. Most of the examined micromechanical models for prediction of the tensile modulus of the nanocomposite were successful despite being based on fiber-shaped fillers. An exfoliated structure of clay within the nanocomposite was assumed for the modeling using a molecular dynamics simulations approach, employing Dreiding, Forcite, and COMPASS force fields, in order to investigate the best one for a successful estimation of elastic modulus. Relative to the experimental modulus values of the nanocomposites, which were around 1100–1200 MPa, the COMPASS force field had the best correlation with the values with a slight departure of about 10%.

Research paper thumbnail of Chemical Modification of Polypropylene by Maleic Anhydride: Melt Grafting, Characterization and Mechanism

International Journal of Chemical Engineering and Applications, 2014

Polypropylene (PP) was functionalized with maleic anhydride (MAH) in the presence of dicumyl pero... more Polypropylene (PP) was functionalized with maleic anhydride (MAH) in the presence of dicumyl peroxide (DCP) via melt grafting in a batch mixer, where the maleic anhydride and peroxide concentrations were varied. The effect of concentration of monomer and initiator on the degree of functionalization and properties of the products was investigated by FT-IR spectroscopy, contact angle measurement, thermal analysis and titration. It was found that the degree of functionalization depends on the initial concentration of monomer and initiator that used in reaction. Finally a mechanism of melt grafting MAH onto PP proposed on the basis of our experimental results and other experimental finding published in the literature.

Research paper thumbnail of 23 Thermal Conductivity of Nanoparticles Filled Polymers

Thermal conductivity of polymers is an important thermal property for both polymer applications a... more Thermal conductivity of polymers is an important thermal property for both polymer applications and processing. Polymers typically have intrinsic thermal conductivity much lower than those for metals or ceramic materials, and therefore are good thermal insulators. Further enhancement of this thermal insulating quality can be achieved by foaming polymers. In other applications which require higher thermal conductivity, such as in electronic packaging and encapsulations, satellite devices, and in areas where good heat dissipation, low thermal expansion and light weight are needed, polymers reinforced with fillers, organic or inorganic, are becoming more and more common in producing advanced polymer composites for these applications (Hodgin & Estes, 1999; Tavman, 2004; Lee & Eun, 2004; Liu & Mather, 2004; Ishida & Heights, 1999; Frank & Phillip, 2002; Hermansen, 2001; Ishida, 2000). Most polymeric materials are processed and fabricated at elevated temperatures, often above their meltin...

Research paper thumbnail of Assessment of Compatibility in Polypropylene/Poly(lactic acid)/Ethylene Vinyl Alcohol Ternary Blends: Relating Experiments and Molecular Dynamics Simulation Results

Journal of Macromolecular Science, Part B

ABSTRACT Two systems of polypropylene (PP), poly(lactic acid) (PLA) and ethylene vinyl alcohol co... more ABSTRACT Two systems of polypropylene (PP), poly(lactic acid) (PLA) and ethylene vinyl alcohol copolymer (EVOH) ternary blends having different compositions were extruded in a co-rotating twin screw extruder. The first system was PP/PLA (75/25) with various EVOH contents, the second one was PP/EVOH (75/25) having various PLA contents. The effects of composition on the morphology and the tensile and impact properties of the blends were investigated. There were increases in the tensile modulus and tensile strength with an increase in the EVOH and PLA contents in the first and second systems, respectively. A molecular dynamics (MD) simulation was used to investigate the compatibility between the components. Prediction of the miscibility of the blends was carried out by determining the interaction parameters (χ), mixing energies (ΔHmix), phase diagrams and Gibbs free energies. The MD simulation showed a UCST behavior for the components. Moreover, the simulation results showed a compatibilizer effect for the EVOH component. The experimental values of the dynamic mechanical thermal analysis (DMTA) and mechanical properties were correlated to the MD results. There was a good correlation between the MD and DMTA results. The modulus values using the parallel and Davis models were near to the experimental ones. A good fitting to the mixture law with addition of EVOH confirmed a good compatibilzing effect of it between the PP and PLA components.

Research paper thumbnail of Comparing the Effect of Micro- and Nano-Scale Silica on the Rheological, Dynamic Mechanical Properties and Flame Resistance of Nylon 6,6

Journal of Macromolecular Science, Part B, 2014

Nylon 6,6 micro- and nano-silica composites were prepared by melt processing using a twin-screw e... more Nylon 6,6 micro- and nano-silica composites were prepared by melt processing using a twin-screw extruder. Three nanocomposites containing 4, 8, and 12 wt.% of nanosilica were prepared. In order to compare the effect of size, a microcomposite containing 4 wt.% of micron-size silica was also prepared. The effects of particle type (micro- and nano-size) on the dynamic thermomechanical and rheological properties, morphology, and flame resistance of the composites were examined. The dynamic thermomechanical properties (DMTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic rheometry, thermogravimetry analysis (TGA), and limiting oxygen index (LOI) data are reported. The particles were observed to be dispersed uniformly, but with a different level of coalescence, by means of SEM and TEM. The DMTA results showed that the damping factor peak positions of the nanocomposites at low content of nanofiller shifted more to higher temperature compared to those of nanocomposites containing high concentrations of nanofiller. Dynamic rheometry, using a parallel plate rheometer, showed that the rheological moduli of the nanocomposites increased with increase in nanofiller concentration; however, this increase was greater in the high-frequency region. These results showed that increasing the concentration of nanofiller, and the consequent coalescence effect within the nanocomposites, led to rheological moduli values similar to those of the microcomposite. The TGA and LOI results of the microcomposite and nanocomposite containing 4wt.% of nanosilica showed that nanosilica had a more significant effect to enhance the heat and flame resistance of nylon 6,6 compared to that of micron-sized silica.

Research paper thumbnail of Preparation and characterization of sodium alginate–PVA polymeric scaffolds by electrospinning method for skin tissue engineering applications

RSC Advances

The main aim of this study was to improve the spinnability of SA by adding PVA. The main paramete... more The main aim of this study was to improve the spinnability of SA by adding PVA. The main parameters in producing nanofiber from the optimized SA:PVA ratio, including voltage, flow rate, and working space, were also optimized.

Research paper thumbnail of Temperature dependency of gas barrier properties of biodegradable PP/PLA/nanoclay films: Experimental analyses with a molecular dynamics simulation approach

Journal of Applied Polymer Science

Research paper thumbnail of Non-isothermal crystallization and oxygen permeability of PP/PLA/EVOH ternary blends

Journal of Thermal Analysis and Calorimetry

Research paper thumbnail of A combined experimental and theoretical approach to quantitative assessment of microstructure in PLA/PP/Organo-Clay nanocomposites; wide-angle x-ray scattering and rheological analysis

Composites Part B: Engineering

Research paper thumbnail of Diffusion of 1,2,3-Benzotriazole as a Volatile Corrosion Inhibitor through Common Polymer Films Using the Molecular Dynamics Simulation Method

Journal of Macromolecular Science, Part B

Research paper thumbnail of Evaluation of mixing efficiency in elaborating of chitosan/cellulose nanocomposite via statistical analyses

International Journal of Biological Macromolecules, 2016

Research paper thumbnail of On O2 gas permeability of PP/PLA/clay nanocomposites: A molecular dynamic simulation approach

Polymer Testing, 2015

ABSTRACT Polypropylene/poly(lactic acid) (PP/PLA) blends were prepared by reactive blending in a ... more ABSTRACT Polypropylene/poly(lactic acid) (PP/PLA) blends were prepared by reactive blending in a co-rotating twin-screw extruder. Effect of blend composition on oxygen permeability through compression molded films was investigated and correlated to the microstructure. Two blends, PP-rich (75/25) and PLA-rich (25/75), were selected in order to consider the effect of incorporation of clay and compatibilization on the permeability. The PP-rich blends had greater oxygen barrier properties compared to those of PLA-rich blends. Several proposed models of permeability for blends and nanocomposites were examined. These models failed to predict the permeability values, especially for PLA-rich blends. The failure was attributed to the immiscibility issue leading to appearance of microvoids at the interface. Molecular dynamics simulations were performed by employing the COMPASS force field to estimate the diffusivity of oxygen gas through pure components, PP-rich and PLA-rich systems. The simulated results were in good agreement with the available experimental data.