Organo-montmorillonite Content Research Articles

The impact of organo‐montmorillonite on rheology and crystalline structure of uncured and cured acrylonitrile‐butadiene rubber/poly(ethylene‐co‐vinyl acetate) nanocomposites

AbstractThe aim of this study was to evaluate the influence of organo‐montmorillonite (OMMT) content on rheology, crystalline structure, and also hardness and tensile properties of uncured and lightly cured acrylonitrile‐butadiene rubber (NBR)/poly(ethylene‐co‐vinyl acetate) (EVA)/OMMT nanocomposites. The nanocomposites containing 0 to 7 wt% OMMT was prepared and then cured with 0.3 wt% dicumyl peroxide. The low‐angle X‐ray diffraction results revealed that curing clearly improved the degree of exfoliation in the materials having high OMMT content. It was found from the hardness and tensile tests that the values of hardness, tensile strength, modulus, and energy at break were higher for the cured nanocomposites than those of the uncured materials in the range of OMMT examined. The results obtained from the Casson plot revealed that the nanofiller played a more effective role in increasing the yield stress of the uncured materials than that of the cured counterparts at a constant OMMT content. The characteristic relaxation time was also progressively increased with OMMT content for the uncured materials; however, the value was higher for the cured materials and it was much less sensitive to the nanofiller content. The I110/I200 peak intensity ratio of EVA calculated from the wide‐angle X‐ray diffraction patterns decreased with increasing in OMMT content for the uncured and cured materials; however, the value was always higher for the cured counterparts.

Preparation of Organo-Montmorillonite Modified Poly(lactic acid) and Properties of Its Blends with Wood Flour.

In this study, poly(lactic acid) (PLA)/wood flour (WF) composites were prepared by first blending PLA with organo-montmorillonite (OMMT) at different contents (0.5, 1, 1.5, and 2 wt %). The physical and mechanical properties of the virgin and OMMT modified PLA and its WF composites were tested. The results showed that: (1) at low OMMT content (<1 wt %), OMMT can uniformly disperse into the PLA matrix with highly exfoliated structures. When the content increased to 1.5 wt %, some aggregations occurred; (2) after a second extruding process, the aggregated OMMT redistributed into PLA and part of OMMT even penetrated into the WF cell wall. However, at the highest OMMT content (2 wt %), aggregates still existed; (3) the highly exfoliated OMMT was beneficial to the physical and mechanical properties of PLA and the WF composites. The optimal group of OMMT-modified PLA was found at an OMMT content of 0.5 wt %, while for the PLA/WF system, the best properties were achieved at an OMMT content of 1.5 wt %.

Preparation of novel organo-montmorillonite and its influence on the acid resistance of hybrid cathodic electrodeposition polyurethane coating

Based on the super-composite effect of clay minerals consisting of silicate layers on the polymer, nano-hybrid organic–inorganic composites have attracted great interest. In this paper, a novel organoclay with reactive hydroxyl group was prepared by incorporation into a hydroxyl-terminated cationic polyurethane oligomer (HTCPU) via interlamination. Sodium montmorillonite was organically modified with HTCPU oligomers in the water medium. The modified organo-montmorillonite was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, and thermogravimetric analysis. After sequential poly-addition reactions, the hydroxyl-terminated polyurethane hybrid resins with nano-silica layers were prepared and then the resin mixed with blocked hexamethylene diisocyanate trimer (crosslinking agent) in advance and then was emulsified with deionized water to produce the nano-hybrid electrophoresis coating. A series of PU films were prepared by the electrophoresis process. The optimized baking temperature was determined by in situ FTIR, and the effect of the organo-montmorillonite content on the acid resistance of film was studied. When the mass fraction of organo-montmorillonite was about 0.35%, the PU film showed the best acid resistance. It was found that the desirable appearance and properties could be obtained by a prebake of a temperature of 80°C to remove water in the wet film to avoid the pinholes in the paint film for 20 min, followed by a baking temperature of 135°C for 60 min.

Effects of Organomontmorillonite Content on Morphology and Mechanical and Thermal Properties of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide-66 Nanocomposites

The nanocomposites consisting of polymer matrix and nanofiller have attracted great attention because of the improved physical properties. In this paper, organomontmorillonite (OMMT) was introduced into poly(2,6-dimethyl-1,4-phenylene oxide) grafted maleic anhydride (PPO-g-MA) compatibilized poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide-66 (PPO/PA66) blends by melt extrusion. The morphology of PPO/PA66 nanocomposites with different amounts of OMMT was investigated using transmission electron microscopy (TEM), wide-angle X-ray diffraction (WAXD), and scanning electron microscopy (SEM). The OMMT platelets exhibited an exfoliated structure in the PA66 matrix and an intercalated structure on the surface of PPO domains at low OMMT loading (2 phr). However, the exfoliated platelets in matrix were found to transform into intercalated stacks by adding 6 phr of OMMT. The mechanical properties and thermal stability were significantly improved with the coexistence of exfoliated and intercalated OMMT at low OMMT loading (2–4 phr). The exfoliated OMMT platelets imposed a confinement effect on the macromolecular chains and thereby increased the storage modulus and complex viscosity of nanocomposites.

Effect of organic modifier type of montmorillonite on the poly (butyl acrylate-co-methyl methacrylate)/montmorillonite nanocomposite

Nanocomposites based on poly(BA-co-MMA) and organo-montmorillonite (OMt) were synthesized by semi batch emulsion polymerization. OMt was used directly after the organic modification of sodium montmorillonite (Mt). By this way, dispersion of OMt in emulsion polymerization was improved. OMts were prepared by organic modification of Resadiye Mt (bentonite) with five different quaternary ammonium salts (QAS) to observe the effect of structural difference on the poly(butyl acrylate-co-methyl methacrylate) nanocomposites. The affinity of OMts towards organic liquids was observed via swelling test in toluene and butyl acrylate (BA)-methyl methacrylate (MMA) mixture. OMt content in the nanocomposite as well as the effect of QAS structure and dosage was investigated. Good dispersion of OMt in copolymer films was obtained as demonstrated by X-ray diffraction and partially exfoliated OMt structure was determined through transmission electron microscope. Final nanocomposites had 47 wt% solids contents. Nanocomposite containing 2.3 wt% OMt modified with two 18 carbons alkyl chain at excess QAS amount resulted in higher increments of thermal, mechanical, barrier properties and glossiness for coating applications.

HIGH-IMPACT PP NANOCOMPOSITES: INFLUENCE OF CLAY CONTENT ON MECHANICAL AND THERMAL PROPERTIES

The preparation of high-impact polypropylene nanocomposites with different organo-montmorillonite (O-MMT) contents by means of meltprocessing was investigated. The nanocomposite properties were evaluated by transmission electron microscopy (TEM), flexural modulus, izod impact strength, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was noticed that the PP/O-MMT nanocomposites properties were affected by clay content. Exceptional improvements in impact strength were obtained (maximum of 185%) by the use of low O-MMT content. The results showed that higher enhancement on mechanical/thermal properties was obtained by 3 wt.% of O-MMT instead of higher quantities.

Preparation, morphology and properties of poly(trimethylene terephthalate)/maleinized poly(octene–ethylene)/organomontmorillonite nanocomposites

In order to improve the mechanical properties, crystallization behavior and processing viscosity of the poly(trimethylene terephthalate) (PTT), maleinized poly(octene–ethylene) (POE) and organomontmorillonite (OMMT) were used to prepare nanocomposites of PTT/POE/OMMT by melt blending method, and their morphology and properties were investigated in detail. The results suggest that some of the OMMTs are peeled off and the nanosheets are dispersed evenly in the polymer matrix. The nanocomposites have higher melt viscosity with increasing OMMT content due to the interaction between OMMTs and polymers, which is favorable for improving the processing property of the material. The nanocomposite with 2 wt% OMMT has the largest tensile and impact strength. The elastic modulus of the glassy nanocomposite increases, and the glass transition temperature first slightly decreases and then increases with increasing OMMT content. The nanocomposites form smaller or imperfect microcrystallites with lower melting point and the nanocomposites have increased crystallization rate because of the effective nucleation agent of OMMT. However, the crystallinity decreases because of the thickening effect of OMMT and POE in the composites. OMMT and POE have small influence on the thermal stability of the nanocomposite.

Morphology and Mechanical Properties of Acrylonitrile-Butadiene-Styrene (ABS)/Polyamide 6 (PA6) Nanocomposites Prepared via Melt Mixing

Acrylonitrile-butadiene-styrene (ABS)/polyamide 6 (PA6) blends containing various amounts of organomontmorillonite (OMMT) were prepared using a twin-screw extruder followed by injection molding. The effect of OMMT on the microstructure and properties of the ternary nanocomposites is investigated by wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and mechanical properties testing. The results showed the OMMT platelets were preferentially located and exfoliated in the PA6 phase, but some were located at the interface of the ABS and PA6 phase. The effect of the addition of the OMMT on the morphology and mechanical properties was also evaluated. SEM revealed that the dimensions of the dispersed PA6 droplets were greatly reduced when the concentration of the OMMT was less than 4 phr. The domain size was less than the neat ABS/PA6 blends with the increasing of the OMMT content. It was suggested that the OMMT can compatibilize the ABS/PA6 blend. In addition, the flexural strength and modulus increased with increasing OMMT content, but the tensile strength became maximal at 3 phr OMMT. The OMMT had a negligible effect on the impact strength of the ABS/PA6 blend nanocomposite.

Study on Mechanical and Ablative Properties of EPDM/OMMT Thermal Insulating Nanocomposites

In order to enhance the elongation at break, the ablation resistant properties as well as the tensile strength of the thermal insulating materials, organo-montmorillonite (OMMT) was introduced into the short aramid fibers reinforced Ethylene-Propylene-Diene Monomer (EPDM) based nanocomposites. The effects of OMMT content on the mechanical and ablative properties of the nanocomposites were investigated systematically. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm that EPDM-matrix has been intercalated into OMMT interlayers after a mixing process on a two-roll mill. The brittle fracture of nanocomposites also indicates that OMMT can lubricate aramid fiber to weaken the interfacial adhesive strength between the fibers and the matrix. As a result, the tensile strength and elongation at break are both improved sharply with OMMT content increasing from 1 phr to 7 phr. However, thanks to the inevitable agglomeration of OMMT with high loading inside the nanocomposites, the tensile strength and elongation at break reduce gently once OMMT is over 7 phr. Furthermore, the ablation resistant properties are improved greatly by increasing OMMT from 1 phr to 11 phr. Therefore, the optimal content of OMMT is 7-11 phr for the thermal insulating nanocomposites with big elongation and excellent ablation resistant properties.

Structure and Properties of Hydrogenated Nitrile Rubber/Organo-Montmorillonite Nanocomposites

AbstractThe aim of the work was to study the effect of organo-montmorillonite (OMt) on the properties of hydrogenated nitrile rubber (HNBR)/OMt nanocomposites. The nanocomposites were prepared by a melt intercalation method. The structure of the composites was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The behavior of stress-strain, aging resistance, solvent resistance, and the dynamic mechanical properties of HNBR/OMt nanocomposites were investigated. The TEM and XRD results showed that the OMt layers were dispersed homogeneously in the HNBR matrix. The HNBR/OMt nanocomposites showed excellent mechanical properties which were attributed to the nanometer scale dispersion and strong interaction between the HNBR and OMt. The composites possessed excellent aging resistance and oil resistance, which improved with OMt content. Dynamic mechanical analysis showed that the glass-transition temperature, Tg, of the HNBR/OMt nanocomposites was increased and the nanocomposites had a good rolling resistance in comparison to pure HNBR. The composites displayed better dynamic mechanical properties.

Structure and Mechanical Properties of Melt Intercalated Po1lypropylene–Organomontmorillonite Nanocomposites

The preparation and properties of polymer nanocomposites, obtained by melt-compounding of polypropylene (PP) and organomontmorillonite (OMMT) modified by different alkyl ammonium salts, are described. A copolymer of maleic anhydride and PP was used as a compatibilizing additive. Nanocomposites with OMMT content of 1, 5 and 10 wt% were prepared and tested. The influence of OMMT content on the tensile stress–strain curves, elastic modulus, yield and tensile strength, and ultimate elongation of the nanocomposites is determined. The results of measuring the microhardness and impact strength of polymer nanocomposites are presented. Long-term creep tests were performed to predict the long-term deformation behavior of nanocomposites. The crystallinity of nanocomposites was analyzed by means of differential scanning calorimetry and optical microscopy, while the structural features were studied by X-ray diffraction and scanning electron microscopy methods.

Preparation and properties of chlorosulfonated polyethylene/organomontmorillonite nanocomposites

Chlorosulfonated polyethylene (CSPE)/organomontmorillonite (OMMT) nanocomposites were prepared by a melt intercalation method. The microstructure of the nanocomposites was characterized by transmission electron microscopy and X-ray diffraction. The effects of the OMMT content on the mechanical properties and swelling behavior of the nanocomposites were investigated. The improvement in the thermal stability of the nanocomposites was determined by thermogravimetric analysis. Transmission electron microscopy and X-ray diffraction showed that CSPE was intercalated into OMMT. When the OMMT content was lower than 12 wt %, the nanocomposites showed excellent tensile properties, which was attributed to nanometer-scale dispersion. The introduction of a small amount of OMMT also improved the thermal stability and swelling behavior, which was attributed to the gas barrier action of the OMMT layers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis, electrorheology, and creep behaviors of in situ intercalated polyindole/organo‐montmorillonite conducting nanocomposite

AbstractIn this study, first polyindole (PIN) was synthesized using FeCl3 as an oxidizing agent. Then, an organo‐montmorillonite (O‐MMT) was prepared from virgin montmorillonite (MMT) by cetyltrimethylammonium bromide (CTAB) quaternary ammonium salt. Further, PIN/O‐MMT conducting nanocomposite was prepared with 18% O‐MMT content. The samples of PIN, MMT, O‐MMT, and PIN/O‐MMT nanocomposite were characterized by FTIR spectroscopy, thermogravimetric analysis (TGA), X‐ray diffraction (XRD), elemental analysis, conductivity, magnetic susceptibility, density, particle size measurements, and scanning electron microscopy (SEM) method. Characterization results showed a successfully prepared PIN/O‐MMT nanocomposite having both intercalated and exfoliated structures. A series of concentrations (5–25%, m/m) were prepared from those above‐mentioned materials in silicone oil (SO) and their sedimentation stabilities were determined. The suspensions were subjected to an external electric field strength and electrorheological (ER) activity was observed. The effects of dispersed particle concentration, shear rate, external electric field strength, frequency, and temperature onto ER activities of these suspensions were investigated. Creep tests were applied to all the four suspensions and recoverable viscoelastic deformations observed. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

Synthesis and antifungal activities of polymer/montmorillonite–terbinafine hydrochloride nanocomposite films

The poly(dimethylsiloxane) (PDMS)/montmorillonite–terbinafine hydrochloride (PDMS/OMMT) nanocomposite films were obtained by solution intercalation. Organo-montmorillonite (OMMT) with antifungal activity was prepared from Na +-montmorillonite (Na +-MMT) and terbinafine hydrochloride (Ter-HCl) by ion exchange. The microstructure of these nanocomposite films were characterized by TEM and XRD. The effect of OMMT on the mechanical properties and thermal stability of the nanocomposites was investigated. When the OMMT content was < 1 mass %, the nanocomposites showed excellent mechanical properties. The polymers were tested for antifungal activity against Candida albicans. The PDMS/OMMT nanocomposite films strongly inhibited the C. albicans.

Preparation and properties of organo-montmorillonite/cis-1,4-polybutadiene rubber nanocomposites by solution intercalation

Organo-montmorillonite (OMMT)/cis-1,4-polybutadiene rubber (BR) nanocomposites were prepared by solution intercalation. The microstructure of these composites was characterized by TEM and XRD. The effect of OMMT on mechanical properties, thermal stability and swelling behavior of the nanocomposites was investigated. TEM and XRD confirmed the intercalated structure of OMMT/BR nanocomposites. When the OMMT content was < 12 mass%, the nanocomposites showed excellent tensile properties, which was attributed to the nanometer scale dispersion and stronger interactions between OMMT and BR chains. The introduction of a small amount of OMMT greatly improved the thermal stability and swelling behavior, which was attributed to the good barrier properties of OMMT layers.

Synthesis and antimicrobial activities of polymer/montmorillonite–chlorhexidine acetate nanocomposite films

The PDMS/montmorillonite–chlorhexidine acetate (PDMS/OMMT) nanocomposite films were successfully obtained by intercalation from solution. Organo-montmorillonite (OMMT) with antibacterial activity was prepared from Na +-montmorillonite (Na +-MMT) and chlorhexidine acetate (CA) by ion exchange. The microstructure of these nanocomposite films were characterized by TEM and XRD. The effect of OMMT on mechanical properties and thermal stability of the nanocomposites was investigated. When the OMMT content was lower than 0.5 mass %, the nanocomposites showed excellent mechanical properties. The polymers were tested for antimicrobial activity against Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli). The PDMS/OMMT nanocomposite films strongly inhibited the growth of a wide variety of microorganisms, including Gram-positive bacteria, Gram-negative bacteria.

Preparation and properties of organo-montmorillonite/fluoroelastomer nanocomposites

Organo-montmorillonite (OMMT)/fluoroelastomer (FKM) nanocomposites were prepared by melt intercalation. The microstructure of these composites was characterized by TEM and XRD. The effect of OMMT on mechanical properties, thermal stability and solvent resistance of the nanocomposites were investigated. TEM and XRD showed that the FKM was intercalated into OMMT. When the OMMT content was lower than 12 wt.%, the nanocomposites showed excellent tensile properties, which was attributed to the nanometer scale dispersion and the higher aspect ratio of the clay mineral layers. The introduction of a small amount of OMMT also improved the thermal stability and solvent resistance, which was attributed to the gas barrier action of the OMMT layers. Compared to pure FKM, the nanocomposites exhibited a higher glass transition temperature and lower tan δ peak value.

Study on superabsorbent composites. XVIII. Preparation, characterization, and property evaluation of poly(acrylic acid‐co‐acrylamide)/organomontmorillonite/sodium humate superabsorbent composites

AbstractA series of novel multifunctional poly (acrylic acid‐co‐acrylamide) (PAA‐AM)/organomontmorillonite (O‐MMT)/sodium humate (SH) superabsorbent composites were synthesized by the graft copolymerization reaction of partially neutralized acrylic acid and acrylamide on O‐MMT micropowder and SH with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator in an aqueous solution. The superabsorbent composites were characterized by means of Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The effect of the relative weight ratio of SH to O‐MMT on the water absorbency was studied, and the results indicated that the best water absorbency of 591 g/g in distilled water was obtained when an O‐MMT content of 20 wt % and an SH content of 30 wt % were incorporated. The superabsorbent composite possessed a good capacity for water retention; even after 30 days, 24.4 wt % of water could still be saved by the sand soil containing 1.0 wt % superabsorbent composite. The results from this study show that the water absorbency of a superabsorbent composite is improved by the simultaneous introduction of O‐MMT and SH into a PAA‐AM network in comparison with the incorporation of only O‐MMT or SH. Also, in comparison with PAA‐AM/MMT/SH, an appropriate amount of O‐MMT can benefit the developed composites with respect to their water absorbency, salt resistance, and capacity for water retention in sand soil. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Preparation and mechanical properties of intercalated PP/OMMT nanocomposites

The preparation of polymer nanocomposites by melt compounding polypropylene (PP) with organically modified montmorillonite using maleic anhydride modified PP as compatibilizer is described. Compositions with organomontmorillonite content 0, 5, 10 wt.% were prepared and tested. Data on the influence of organomontmorillonite content on the tensile stress–strain curves, elastic modulus, strength, and ultimate elongation of the nanocomposites are obtained. The concentration dependences of elastic properties of materials with differently oriented plate like nanoparticles analyses taking into account hierarchical structure features of nanocomposites is considered. Theoretical analysis results are compared with experimental data. The presence of unexfoliated particles in the form of multilayer packages must be taken into account. The results of an investigation of hardness, impact strength, and thermal properties of polymer nanocomposites are presented. Tension creep tests were performed to predict nanocomposites long term deformation behaviour.

A nanocomposite based on a styrene-acrylate copolymer and organically modified montmorillonite 2. Barrier and thermal properties

The results of an investigation into the barrier and thermal properties of polymer nanocomposites prepared by blending a styrene-acrylate copolymer solution with a suspension of organically modified montmorillonite are presented. The influence of organomontmorillonite content on the barrier properties of the nanocomposite is investigated with the example of water vapor permeability. The experimental values of the permeability coefficient are compared with those calculated by using a model taking into account the increased path of diffusing water molecules caused by the shielding effect of plate like particles. The thermograms of differential scanning calorimetry in the temperature range from −40 to 130°C are presented. The results of a thermogravimetric analysis for specimens heated in air to 800°C are also reported.