Melt Intercalation Method Research Articles

Preparation and characterization of poly(ethylene glycol)/organo-vermiculite nanocomposite polymer electrolytes

Vermiculite (VMT) was readily intercalated by hexadecyl trimethyl ammonium bromide to yield organo-vermiculite (OVMT), which was confirmed by X-ray diffraction measurement and Fourier transform infrared spectroscopy. Poly(ethylene glycol)/organo-vermiculite (PEG/OVMT) nanocomposites were prepared by using the direct melt intercalation method, and its intercalation state was confirmed by transmission electron microscope. Thereafter, a lithium salt was dissolved in the PEG/OVMT nanocomposites to prepare composite polymer electrolytes. The highest conductivity was 2.1 × 10−5 S cm−1 at room temperature, which was obtained by AC impedance analysis when the amount of OVMT based on PEG was 1 wt%.

Effects of organo‐clay modifier on physical–mechanical properties of butyl‐based rubber nano‐composites

AbstractBladders are important rubber parts used for shaping and curing of tires. These parts are exposed to high temperature, high pressure, medium‐large extension, and oxidative aging during their service life. Curing bladders are usually made of butyl‐based rubber compounds vulcanized with phenolic resin vulcanization systems. To study the effect of Montmorillonite nano‐clay on properties of these rubber parts and their functionality during service, the most compatible and well dispersed organically modified Montmorillonite (OMMT) nano‐clay has to be selected. To study the effects of organic modifier on properties of these compounds, five types of commercial OMMT were mixed with the compounds using the melt intercalation method. Effect of modifiers on compatibility between clay and rubber, dispersion of clay in the polymer matrix, and thus mechanical properties of the nano‐composite were studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), mechanical tension, and dynamic‐mechnical‐thermal analysis (DMTA). XRD results revealed an intercalated structure for all OMMTs, but with different degrees of rubber intercalation. The largest change in interlayer spacing of silicate layers due to intercalation of rubber was seen for an OMMT modified by dimethyl‐benzyl‐hydrogenated tallow, quaternary ammonium. AFM and SEM micrographs of the latter compound confirmed the intercalated structure with a good distribution of filler. Viscoelastic properties obtained from DMTA confirmed more compatibility between butyl‐based rubber compound and this OMMT. This modified clay was selected as the filler of choice for potential application in actual bladder compound. Uni‐axial tension tests could also differentiate among nano‐composites reinforced with differently modified clays. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

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

Influence of PP‐g‐MA on morphology, mechanical properties and deformation mechanism of copolypropylene/clay nanocomposite

AbstractCopolypropylene/organoclay nanocomposites are prepared by melt intercalation method in this research. Two different routes for addition of compatibilizer are examined, i.e. addition in the twin‐screw extruder along with the polymer and the clay powder simultaneously and premixing the compatibilizer with the reinforcement in a batch mixer before addition to the polypropylene (PP) matrix. Morphology, tensile and impact properties and deformation mechanisms of the samples made via two procedures are studied and compared with those of the noncompatibilized system. To study the structure of nanocomposites, x‐ray diffraction and transmission electron microscopy techniques are utilized. The deformation mechanisms of different samples are examined via reflected and transmitted optical microscopy. The results reveal that introduction of compatibilizer and also the procedure in which the compatibilizer is added to the compound, affect structure and mechanical properties of nanocomposite. The elastic modulus of PP‐clay nanocomposite has increased 11.5% with incorporation of compatibilizer. Also, introduction of organoclay without compatibilizer facilitates crazing at the notch tip of PP in 3PB testing. Incorporation of compatibilizer, however, makes difficulties in initiation and growth of crazes at the notch tip. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Morphology, biodegradability, mechanical, and thermal properties of nanocomposite films based on PLA and plasticized PLA

AbstractIn this study, melt intercalation method is applied to prepare poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG)‐plasticized PLA nanocomposite films including 0, 3, and 5% organoclay (Cloisite 30B) using a laboratory scale compounder, which is connected to a microcast film device. To evaluate the nanomorphology and the dispersion state of the clays, X‐ray diffraction (XRD) and transmission electron microscopy (TEM) are conducted. Tensile tests are performed to characterize the mechanical behavior of the films. Biodegradation rate is determined by degradation tests in composting medium. Differential scanning calorimeter (DSC) is applied to observe the thermal behavior of the films. XRD and TEM show that the exfoliation predominantly occurrs in plasticized PLA nanocomposites, whereas unexfoliated agglomerates together with exfoliated clays are observed in the nonplasticized PLA. Tensile tests indicate that the addition of 3% clay to the neat‐PLA does not affect the strength; however, it enhances the modulus of the nanocomposites in comparison to neat‐PLA. Incorporation of 3% clay to the plasticized PLA improves the modulus with respect to PLA/PEG; on the other hand, the strain at break value is lowered ∼ 40%. The increase in the rate of biodegradation in composting medium is found as in the order of PLA > PLA/PEG > 3% Clay/PLA/PEG > 5% Clay/PLA/PEG > 3% Clay/PLA. DSC analysis shows that the addition of 3% clay to the neat PLA results in an increase in Tg. The addition of 20% PEG as a plasticizer to the neat‐PLA decreases Tg about 30°C, however incorporation of clays increases Tg by 4°C for the plasticized PLA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

An Investigation of the Flammability, Morphology and Torque Rheology of Poly(Vinyl Chloride) with Silanes and Cu2+ Modified Montmorillonites

Silane-modified montmorillonites(MMTs) and Cu2+-silane modified MMTs have been prepared by treating Na+ montmorillonites (Na+-MMTs) with silane coupling agents and copper (II) sulfate, and poly(vinyl chloride)(PVC)/modified MMT composites were prepared by using a twin-screw extruder. The microstructures of the modified MMTs and the composites were characterised by XRD and SEM. The results indicated that the silanes and Cu2+ were intercalated into the interlayers, and that the silane-modified MMTs and Cu2+-silane modified MMTs were exfoliated and dispersed in PVC by the melt-intercalation method. A small amount of Cu2+ was observed to shorten slightly the interlayer spacing of MMTs. The cone calorimetric data demonstrated that Na+-MMTs and modified MMTs changed the flammability behaviour of the composites; they effectively reduced the peak heat release rate (pk-HRR), peak smoke production rate (pk-SPR), total smoke production (TSP) and ignition time (IT). Cu2+-silane modified MMTs presented a better smoke suppressant effect than Na+-MMTs and silane modified MMTs, and the smoke-reducing efficiency of Cu2+-silane modified MMTs reached 44% although the Cu2+-silane modified MMTs contained only a small amount of copper (II) ion, 0.6~0.8%. The torque experiments indicated that silane modified MMTs improved the processability of the composites, while Cu2+-silane modified MMTs obviously increased the plasticising time of the composites. The tensile strength and flexural strength of the composites increased compared with PVC/Na+-MMTs composite.

Isothermal crystallization and melting behavior of polypropylene/layered double hydroxide nanocomposites

The effect of layered double hydroxide (LDH) nanolayers on the crystallization behavior of polypropylene (PP) was studied based on the preparation of nanocomposites by a melt intercalation method. The isothermal crystallization kinetics and subsequent melting behavior of PP/LDH hybrids were studied with differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). Studies revealed that the LDH promoted heterogeneous nucleation, accelerating the crystallization of PP. The Avrami equation successfully describes the isothermal crystallization kinetics of PP/LDH hybrids and signifies heterogeneous nucleation in crystal growth of PP. The varying values of Avrami exponent ( n) and half crystallization time ( t 1/2) of PP and PP/LDH hybrids describes overall crystallization behavior. The crystallite size ( D h k l ) and distribution of different crystallites in PP varied in presence of LDH. A significant increase in melting temperature is observed for PP/LDH hybrids. The POM showed that smaller and less perfect crystals were formed in nanocomposites because of molecular interaction between PP chains and LDH. The value of fold surface free energy ( σ e) of PP chains decreased with increasing LDH content. Finally, the overall results signify that LDH at nanometer level acted as nucleating agent and accelerate the overall crystallization process of PP.

Synergistic flammability and thermal stability of polypropylene/aluminum trihydroxide/Fe‐montmorillonite nanocomposites

AbstractIn the present study, polypropylene/aluminium trihydroxide/Fe‐montmorillonite (PP/ATH/Fe‐MMT) nanocomposites were prepared by melt‐intercalation method. This was been designed to determine whether the presence of structural iron in the matrix could enhance the thermal stability and flammability of nanocomposites. In order to prove the effect of Fe3+ in the structural silicate layers, samples of PP/ATH and PP/ATH/Na‐MMT (no Fe3+ in structural silicate layers) were prepared under the same conditions. Fe‐MMT and Na‐MMT were modified by cetyltrimethyl ammonium bromide (CTAB). The nanocomposite structures were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) was applied to test the thermal properties of nanocomposites. In addition, the limiting oxygen index (LOI) of PP/ATH/Fe‐MMT nanocomposites was increased, and no dripping phenomenon was found through the UL‐94 vertical burning test. Copyright © 2009 John Wiley & Sons, Ltd.

Comparison Between Structures and Properties of ABS Nanocomposites Derived from Two Different Kinds of OMT

In the present work, the hexadecyl triphenyl phosphonium bromide (P16) and cetyl pyridium chloride (CPC) were used to modify montmorillonite (MMT) based on the structural characteristic of the engineering thermoplastic acrylonitrile-butadiene-styrene copolymer (ABS) and the principle of “like dissolves like”, and then used to prepare the ABS/organic-modified montmorillonite (OMT) nanocomposites by melt-intercalation method. The influences of two different kinds of OMT on the structures and properties of the ABS nanocomposites were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HREM), thermogravimetric analyses (TGA), Cone calorimetry and dynamic mechanical analyses (DMA), respectively. The increased basal spacing showed that ABS intercalated into the gallery of the OMT. The morphology indicated that the OMT dispersed well in the ABS resin and the intercalated structure for ABS/OMT-P16 nanocomposites and intercalated-exfoliated structure for ABS/OMT-CPC nanocomposites were respectively formed. The TGA results revealed that onset temperature of thermal degradation and charred residue at 700 °C of the ABS nanocomposites was remarkably enhanced compared to the pure ABS. It was also found from the Cone calorimetry tests that the peak of heat release rate (PHRR) decreased significantly, contributing to the reduced flammability. The DMA measurements indicated that the loading of silicate clays improved the storage modulus of the ABS resin. The partial exfoliation of the OMT-CPC within ABS nanocomposites was advantageous to increasing thermal stability properties, decreasing flammability properties, and improving mechanical properties.

Flame Retardant and Smoke Suppressant of Fe‐Organophilic Montmorillonite in Polyvinyl Chloride Nanocomposites

AbstractTwo kinds of polyvinyl chloride (PVC)/organophilic montmorillonite (OMT) nanocomposites are prepared by a melt intercalation method. This study has been designed to determine if the presence of iron and zinc ions in the structure of montmorillonite (MMT) lattice can affect thermal, flame retardant and smoke suppressant properties. The information about the morphological structure of PVC/OMT nanocomposites was obtained using X‐ray diffraction and transmission electron microscopy. The thermal and flame retardant properties of the nanocomposites were characterized by thermogravimetric analysis, limiting oxygen index and smoke density. The nanocomposites based on Fe‐OMT exhibit better thermal, flame retardant properties and lower degradation degree than those of pure PVC. The degradation mechanism was studied by pyrolysis, gas chromatography and mass spectrometry (Py‐GC‐MS).

Thermal stability, mechanical and adsorption resistant properties of HDPE/PEG/Clay nanocomposites on exposure to electron beam

AbstractThe Influence of electron beam on behaviors of high density polyethylene/poly(ethylene glycol)/organoclay nanocomposites has been studied. Nanocomposite compounds were prepared by melt intercalation method. X-ray diffraction (XRD) and transition electron microscopy (TEM) revealed the combination of nanocomposite morphology. Thermal and mechanical properties of nanocomposites were studied by using Thermogravimetric analysis (TGA), Young's modulus, tensile strength and hardness tests. The results show that at 500 KGy dose of irradiation the Young’s modulus and tensile strength values have been enhanced in comparison with pure blend by cross-linking and the surface hardness of samples raises by increasing the clay content The samples with the clay content of 5 wt% in the matrix with 500KGy dose of irradiation have shown satisfactory thermal resistance.The irradiation at high levels has degraded the nanocomposites and an optimum dose must be employed to enhance their properties. The presence of poly(ethylene glycol) as a compatibilizer has improved the dispersion of clay layers into the matrix and has enhanced the mechanical properties and thermal resistance of nanocomposites. The presence of the clay in the matrix has increased the adsorption amount of xylene and toluene into the bulk of nanocomposites and the irradiation has decreased this capacity by the dose level.

Bentonite-Based Organoclays as Innovative Flame Retardants Agents for SBS Copolymer

Two organophilic bentonites, based on nitrogen-containing compounds, have been synthesised via ion exchange starting from pristine bentonite with octadecyltrimethylammonium bromide (OTAB) and with synthetic melamine-derived N2,N4-dihexadecyl-1,3,5-triazine-2,4,6-triamine (DEDMEL). The chemical and morphological characterization of the organoclays was based on XRD, TEM, Laser Granulometry, X-Ray Fluorescence and CEC capacity. Copoly(styrene-butadiene-styrene)-nanocomposites (SBS-nanocomposites) were obtained by intercalation of the SBS-copolymer into these new organoclays by melt intercalation method. XRD and TEM analysis of the organoclays and of the micro/nano-composites obtained are presented. The effect of the organoclays on the SBS-nanocomposite's flammability properties was investigated using cone calorimeter. An encouraging decrease of 20% in the peak heat released rate (PHRR) has been obtained confirming the important role of melamine's based skeleton and its derived organoclays to act as effective fire retardants and for the improvement of this important functional property in SBS copolymers.

The preparation of PVDF/clay nanocomposites and the investigation of their tribological properties

Poly(vinylidene fluoride) (PVDF) nanocomposites with different content of nanoclay were prepared by melt-intercalation method. The tribological behaviors of the PVDF/clay nanocomposites against 45 # carbon steel ring were evaluated on a block-on-ring type (M-2000) wear tester. Transmission electron microscopy (TEM) observation showed the dispersion of nanoclay in PVDF matrix. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis found that nanoclay incorporation induced the PVDF crystal form to transform from α- to β-phase, and hence increased the materials polarity. Differential scanning calorimetry (DSC) analysis verified that the crystallinity of the nanocomposites decreased with the increasing nanoclay content. Nanoclay at 1–2 wt.% was effective for improving the tribological properties of neat PVDF, because the nanoclay at the low content may act as the reinforcing element to bore load and thus decrease the plastic deformation. The nanocomposite containing 5 wt.% nanoclay exhibited relatively high wear, weak compatibility between nanoclay and PVDF and also the decreased crystallinity may be responsible for the result.

Preparation and characteristics of polypropylene/nylon/montmorillonite flame retardant nanocomposites

In this paper, nylon was used as carbonisation agent instead of pentaerythritol (PT), and the melt intercalation method was used to synthesise polypropylene (PP)/nylon (PA6)/montmorillonite (MMT) flame retardant nanocomposites. The structure and flammability property of products were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis (TGA), cone calorimeter test, limiting oxygen index and vertical burning test. The results showed that the polymer chain was intercalated into the MMT's interlayer and the MMT dispersed into PP/PA6 matrix in the form of intercalation to get flaky texture. The appropriate content of MMT in composition is 4–6 mass%. The use of intercalated MMT increased the tensile strength of materials by 15·0% and the impact strength by 69·5%, and improved the flame retardant properties. The TGA showed that the char residue rate reached 12·3%. The cone calorimeter experiments indicated that the peak of heat release rate reduced by about 87% in comparison with the pure PP and the residue weight increased. The vertical burning test (UL 94) results indicated that the materials achieved V-0 grade.

Linear and nonlinear melt‐state viscoelastic properties of polypropylene/organoclay nanocomposites

AbstractRheological behavior of polypropylene (PP)/organoclay nanocomposites varying in compatibilizer (PP‐g‐MA) and organoclay concentration was investigated. The samples were prepared by melt intercalation method in an internal mixer. The wide angle X‐ray diffraction patterns and results of rheological measurements showed that the compatibilizer had strong influence in increasing the interlayer spacing. The observed low frequency liquid‐like to solid‐like transition and apparent yield stress in simple shear flows, along with convergence of transient shear stress to nonzero values in stress relaxation after the cessation of flow experiments, were found to be consistent with formation of a physical network in quiescent conditions which could be easily ruptured with applying low shear rates. The values of stress overshoot strain in flow reversal experiments were independent of shear rate, organoclay, and compatibilizer content. From the results of frequency sweep experiments in different nonlinear strain amplitudes it was shown that extended Cox‐Merz analogy was valid in nonlinear dynamic deformations while the shear viscosity showed positive deviation from this analogy with higher deviations at lower shear rates. Results of storage modulus recovery and flow reversal experiments at different shear rates suggested that network structure is reformed with a much slower rate compared to the rotational relaxation of organoclay platelets. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Effect of EPM-g-MAH on the Flexural and Morphological Properties of Poly(lactic acid)/Organo-montmorillonite Nanocomposites

Poly(lactic acid) (PLA)/organo-montmorillonite (OMMT) nanocomposites were prepared by using both solution intercalation and melt intercalation methods. Maleic anhydride grafted ethylene propylene rubber (EPM-g-MAH) was used as a toughening agent for the PLA/OMMT nanocomposites. The flexural properties of PLA/OMMT nanocomposites were studied by using three-point bending test (ASTM D790). The structure of PLA/OMMT nanocomposites has been investigated by using a wide-angle X-ray Diffraction (XRD) analysis. The microstructures of the PLA/OMMT nanocomposites were assessed by Field Emission Scanning Electron Microscopy (FESEM). The flexural yield displacement of PLA/OMMT prepared by melt intercalation method was increased by the addition of EPM-g-MAH. FESEM micrographs show that more fibrillated structure could be observed from the fractured surface of PLA/OMMT/EPM-g-MAH nanocomposites prepared by melt intercalation method. XRD results revealed the formation of PLA nanocomposites as the OMMT was intercalated and exfoliated.

Flexural, Morphological and Thermal Properties of Poly(Lactic Acid)/ Organo-Montmorillonite Nanocomposites

Poly(lactic acid) (PLA)/organo-montmorillonite (OMMT) nanocomposites were prepared by using solution intercalation and melt intercalation methods. For solution intercalation method, toluene was used as solvent. For melt intercalation method, PLA/OMMT composites were prepared by using single-screw extruder. The flexural properties of PLA/OMMT composites have been studied by using three point bending tests. Comparisons between the flexural properties of PLA/OMMT nanocomposites prepared by both methods have been carried out. The microstructures of the PLA/OMMT nanocomposites were assessed by Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis. The thermal properties of PLA/OMMT nanocomposites have been characterized by using Differential Scanning Calorimeter (DSC). The flexural modulus of PLA/OMMT nanocomposites prepared by both solution intercalation and melt intercalation methods increased significantly by the addition of OMMT. For both methods, it was found that the optimum flexural properties of the PLA nanocomposites was achieved at 1 wt.% OMMT loading. The dispersion of OMMT in the PLA prepared by solution intercalation is better than that of melt intercalation method. This is attributed to the ease of intercalation of PLA chain into the OMMT layered silicate during the solution intercalation process. XRD results revealed that intercalation of OMMT layered silicate occurred in the PLA matrix.

Preparation of Recycled Polypropylene/ Organophilic Modified Layered Silicates Nanocomposites Part I: The Recycling Process of Polypropylene and the Mechanical Properties of Recycled Polypropylene/Organoclay Nanocomposites

The recycling process of polypropylene (PP) and the elaboration of recycled polypropylene/modified clay nanocomposite by melt intercalation method have been investigated. The purpose of this work is to characterize the influence of the recycle processing of an homopolypropylene on the mechanical, thermal, and rheological properties of the polymer, and then to obtain a predictive mechanism of polypropylene degradation in a twin-screw extruder in order to be able to reinforce its behavior for a new application. We can see that the mechanical properties decrease according to the recycling times at two chosen different temperature profiles. At the high temperature profile (195—230°C), the rheological behavior of homopolypropylene is more influenced than at the low temperature profile (175—190°C), the viscoelastic properties are highly modified, the viscosity increases, and the mechanical properties decrease as much as the polypropylene matrix appears to be less accurate. The thermal properties of the recycled polypropylene are investigated by differential scanning calorimetry (DSC) analysis: the crystallization temperature and crystallization time decrease as a function of the number of extrusion cycles. The incorporation of the organophilic layered silicates and maleic anhydride grafted polypropylene (MAPP) compatibilizer improves significantly the mechanical properties of the recycled polypropylene.

Role of primary amine in polyoxymethylene (POM)/bentonite nanocomposite formation

Polyoxymethylene (POM)/organo-modified bentonite nanocomposites are successfully prepared by melt intercalation method of which a primary ammonium salt is an effective surfactant, as evidenced from improvement in mechanical and gas barrier properties. Nanocomposite structures analyzed by XRD and TEM show mixed nanostructure of flocculation and exfoliation (flocculated/exfoliated nanocomposite) when primary ammonium-treated bentonite is used, whereas the quaternary ammonium-treated bentonites induce the mixture of intercalation and flocculation (intercalated/flocculated nanocomposite). The incorporation of organo-modified bentonite gives an effect on crystallization by generating numerous nucleating sites, especially in the case of bentonite with primary ammonium surfactant. The nanocomposites obtained exhibit improvement in flexural strength, flexural modulus, and elongation at break. The thermal degradation temperature is decreased by 40°C, whereas the oxygen barrier is increased by 50%, as compared to neat POM.

Preparation and Chracterization of Nanocomposites of Polyamide 6/Brazilian Clay with Different Organic Modifiers

Nanocomposites of PA6 / organoclay at different concentration were prepared via melt intercalation method using a corotating twin screw extruder. The composites were prepared with Brazilian clay that was treated with different modifiers based on quaternary ammonium salts to obtain three types of organoclays. After extrusion the mixtures were injection molded into specimens that were tested to obtain the properties of tensile strength, notched izod impact and heat deflection temperature. The structure and morphology of the nanocomposites were characterized by x-rays diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the modifier “dodigen” which promoted the intermediate expansion of the bentonite clay within the three salts used for the modification of the clay affects more significantly the mechanical properties, HDT and morphology of the polyamide 6 due to the higher level of exfoliation observed in these systems compared to the others modifiers. The improvement of the properties was correlated to the level of exfoliation/intercalation obtained which depends on the process technique used, surface treatment of the Brazilian clays with organic salts and interaction between polymer and clay.