Amount Of Organoclay Research Articles

Comparing of melt blending and solution mixing methods on the physical properties of thermoplastic polyurethane/organoclay nanocomposite films

In this study, microstructural features and physical properties of thermoplastic polyurethane (TPU)/organoclay nanocomposites films prepared via melt blending (MB) and solution mixing (SM) methods were investigated in detail. Amount of organoclay into the composition varied in the range of 2 and 8 wt%. Microstructural properties of samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. It was found that the organoclay layers exhibited better dispersion, exfoliated, and semi-exfoliated structure in the MB samples than the SM counterparts. Viscoelastic properties of samples were also studied by measuring the rheological behaviors of bulk samples in an oscillatory rheometer in the melt state and measuring of the time-dependent nonlinear creep behaviors of film samples in a dynamic mechanical analyzer in the solid state. Gas and water vapor permeability (WVP) values of nanocomposite films were measured. Based on the melt rheology measurements, it was found that the MB samples showed characteristic solid-like behavior and higher improvement in storage modulus at low-frequency region. Creep behaviors of samples were also quantified with the four-element Burger model. It was found that the introducing of organoclay into the composition via MB method yielded more improvement in the creep resistance, gas, and WVP values of films than the SM counterparts, possibly due to the better dispersion of organoclay layers into the TPU structure. Based on the improvement in permeability and mechanical properties of the samples and also SEM and TEM observations, the average aspect ratio value ( Af) of organoclay stacks was estimated in the range of 15–20 for the MB samples.

The use of relaxometry to evaluate the aging process in hybrid HIPS nanocomposites

Nuclear magnetic resonance allows measurement of proton spin-lattice relaxation times, which reflect the molecular mobility of the sample according to the changes in its chemical structure caused by different mechanisms that can be induced. Nanomaterials and their derivatives are good systems to investigate through NMR relaxometry due to their particular organization and intermolecular interaction. In this study, NMR relaxometry was employed to evaluate UV aging of HIPS nanomaterials formed by the solution method. The results obtained were quite interesting. Regardless of organoclay amount, the aging effect occurred slowly up to 200 h of UV light exposure. However, at 300 h of UV light exposure, competition between chain degradation and chain recombination occurred, and at 400 h the aging effect increased the chain scission.

PP/EPDM Blends Compatibilized by Organically Modified Clays

In this study, the influence of type and amount of organoclay in the morphology of the polymer blend PP/EPDM is evaluated. Pure and filled mixtures were prepared by melt intercalation in an internal mixer. The morphology of the hybrids was evaluated by X-ray diffraction and scanning electron microscopy. The results showed that the incorporation of the organophyllic clay to the PP/EPDM blend resulted in new interfacial interactions between components, which contributed to a decrease in the size of the dispersed phase and the compatibility of the blends. Therefore, organoclays may be employed to compatibilize polymeric blends, replacing conventional compatibilizers.

Effect of matrix morphology on mechanical and barrier properties of polypropylene nanocomposite films containing preferentially aligned organoclay platelets

The objective of this research was to study and optimize the effect of matrix morphology on the desirable mechanical and barrier properties of polypropylene/organoclay (PP/clay) nanocomposite films. Nanocomposites with different organoclay contents and three different matrix morphologies were compared with neat PP under identical conditions. The degree of organoclay dispersion was controlled through the use of a compatibilizer, maleic anhydride grafted polypropylene (PP-g-MA). The nanocomposite films were first prepared by melt casting and then subjected to annealing and re-crystallization. Organoclay platelets in all films were found to align parallel to the film plane. Crystalline PP in as-prepared films was found to have a preferred orientation with the lamellae normally lying perpendicular to the machine direction. Upon annealing, the stacks of parallel lamellae, aligned perpendicular to the machine direction and the film surface, tend to be more orderly than in as-prepared films (see models). No crystal orientation was found in re-crystallized films. A clear increase in elastic modulus and tensile strength with increasing organoclay content was observed. Relative oxygen permeability (ROP) of nanocomposite films decreased with increasing amount of organoclay. The effect of matrix morphology is as follows: annealed films display the highest elastic modulus, tensile strength and ROP, followed by as-prepared and re-crystallized films.

Polymer Nanocomposite of PVDF/Organoclay-Copper Nanoparticles hybrid: Synthesis and Characterization

Poly(vinylidene fluoride) (PVDF) nanocomposite materials filled with a hybrid of organoclay and/or copper nanoparticles were successfully prepared. The synthesis of copper nanoparticles was achieved without the use of a conventional chemical stabilizer, only the organoclay surface serving as a stabilizing agent for the nanoparticles. The results showed the size of the nanoparticles decrease as the organoclay amount increases and less aggregation of the nanoparticles is observed when the particles are on the organoclay surface. Physical and chemical properties were probed using a host of analytical techniques. X-ray Diffraction (XRD) showed successful formation of copper nanoparticles as shown by peaks at 2θ = 460 of the <111> orientation. The prepared hybrids were then used to produce the PVDF nanocomposites membrane sheets. The morphologies of the fabricated nanocomposites sheets were compared using scanning electron microscope (SEM). Atomic force microscope (AFM) showed the change in surface properties and roughness as the hybrid materials were added.. Addition of the hybrid into the PVDF polymer didn’t affect the chemical structure of the polymer as confirmed by the Fourier Transform Infrared Spectroscopy (FT-IR) even when the organoclay content was increased.

Effect of organo-clay on properties and mechanical behavior of Fluorosilicone rubber

High performance Fluorosilicone rubber (FS)/organoclay (OC) nanocomposites have been prepared by a melt compounding process. The results of mechanical investigation revealed that Young’s modulus and hardness of FS rubber are improved with introduction of OCs while an inverse trend was observed for elongation at break and tensile strength. Eight constitutive models, Yeoh, Arruda-Boyce, Mooney-Rivilen, Neo-Hookean, Marlow, polynomial, Van der Waals, and Odgen were studied to investigate the stress-strain behavior of FS/OC nanocomposites. It was concluded that the ability of these models to predict the true behavior of the FS/OC samples directly depends on the amount of OC. Two modified Halpin-Tsai and inverse rule of mixtures theories were applied to evaluate the dependence of Young modulus of nanocomposites on volume fraction of OCs. The experimental data were employed for determining modified models parameters as well as for validating models. It was shown that, OCs can also play a fundamental role in controlling volume shrinkage of FS after cure. FS was proved that still retain its specific properties as well as the fuel and thermal resistance after introduction of OCs. Combination of these results verifies that incorporation of OCs can provide tailored mechanical properties without sacrificing fuel and thermal resistance of FS elastomers.

Nanoparticle-induced co-continuity in immiscible polymer blends – A comparative study on bio-based PLA-PA11 blends filled with organoclay, sepiolite, and carbon nanotubes

Different amounts of organoclay, sepiolite, and carbon nanotubes are added to an immiscible blend of poly(lactic acid) (PLA) and polyamide 11 (PA11) with drop-matrix morphology aiming at elucidating the mechanisms through which unevenly distributed nanoparticles may induce co-continuity. Morphological and dynamic-mechanical analyses show that the three fillers, preferentially located inside the minor PA11 phase, are all able to convert the drop-matrix morphology of the blend into a stable, highly co-continuous one provided a critical nanoparticle loading is exceeded. The cross-checking of the experimental results reveals that co-continuity occurs when the strength of the particle network encapsulated inside the PA11 is sufficient to balance the inclination of the stretched polymer domains to retract back towards lower aspect ratio shapes driven by interfacial tension. A single dimensionless group that combines the yield stress of the filled PA11, the bending resistance of the nanoparticles, and the PLA-PA11 interfacial tension, seems able to rationalize our data, providing a general criterion for the optimal selection of fillers suitable to induce co-continuity in immiscible polymer blends.

Structural and thermodynamics properties of organo-modified montmorillonite clay

Polymer clay nanocomposites (PCNs) have been seen as the most novel materials in engineering applications since they exhibit significant improvement in mechanical and physical properties. Indeed, with few amount of organoclay, PCNs exhibit enhanced mechanical, optical, thermal and liquid or gas barrier properties compared to pure polymers and to their counterpart microcomposites. Thus, organoclays are extensively used as precursors in the preparation of PCNs. They are the best candidate in reinforcing PCNs because of the lightweight and the high availability of clay minerals in the nature. However, structure and physical phenomena arising at molecular level in organoclays, and subsequently in PCNs, are not completely or difficultly accessible with existing experimental techniques. In this work, molecular dynamics (MD) simulation was conducted using the combination of two force fields (CLAYFF and CHARMM) to evaluate the thermodynamics and structural properties of organoclay such as heat capacities, isothermal bulk modulus, density, basal spacing and chains arrangement in the interlayer spacing. Our results regarding the basal spacing and density are in fairly good agreement with available experimental data. This allows us to validate the use of the two force fields to represent interactions in organoclays. The effect of the cation exchange capacity (CEC) on the basal spacing and the thermodynamics properties is assessed. We found, through our MD simulation, that the calculated isothermal bulk modulus is in good agreement with the density value of organoclays with two different CEC.

Effect of organoclay reinforcement on the curing characteristics and technological properties of styrene-butadiene rubber

Rubber nanocomposites based on styrene–butadiene rubber (SBR) and organophilic layered silicate were prepared. Clay structures based on dodecyl benzene sulfonic acid (DBSA), nonyl phenol ethoxylate (NPE), and DBSA/NPE (50/50%) were prepared and characterized. The results indicate the intercalation of the used surfactants within the clay layers. Varying amount of organoclay, 2, 4, 6, 8, and 10 (phr), was added to the SBR matrix. X-ray diffraction revealed exfoliated structure for the modified clay–SBR composites. No new component in the rubber was found by fourier transform infrared measurements (FTIR). Scanning electron microscopy showed a uniform distribution of the modified clay with mixed DBSA/NPE (6 phr) in the matrix. The rheometric characteristics and physicomechanical properties of the SBR compounds were analyzed. The effect of DBSA/NPE clay loading on aging resistance of SBR nanocomposites at 90 ± 1°C for 4 and 7 days was also investigated. Rubber nanocomposites displayed an increase in the minimum and maximum torques, acceleration of the vulcanization process, and improved mechanical properties, with organoclay content up to 6 phr. This effect was more noticeable in the presence of the treated clay with DBSA/NPE. Also incorporation of DBSA/NPE-clay (6 phr) resulted in significant improvement of the degradation profile of the nanocomposites at 90 ± 1°C for 4 days. POLYM. COMPOS., 36:1293–1302, 2015. © 2014 Society of Plastics Engineers

Removal of Basic Dye from Aqueous Solutions Using a Novel Nanocomposite Hydrogel: N-Vinyl 2-Pyrrolidone/Itaconic Acid/Organo Clay

In this work, N-vinyl-2-pyrrolidone/itaconic acid/organo clay nanocomposite hydrogels were synthesized by free radical polymerization technique using different amounts of organo clay. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy techniques were used for characterization of nanocomposite hydrogels and swelling, and mechanical properties of these hydrogels were investigated. Safranine-T adsorption capacities of nanocomposite hydrogels were investigated at different conditions such as pH, contact time, adsorbent dose and initial concentration of dye. The optimum pH value was found to be pH 6. According to the organo clay content, there are no significant differences in dye adsorption capacities of nanocomposite hydrogels until the clay content reaches 5 % wt. While the organo clay amount of nanocomposite hydrogels increases up to 10 % wt, dye adsorption capacities of these hydrogels significantly decrease. Adsorption processes of dye onto the nanocomposite hydrogels follow pseudo-second-order type adsorption kinetic. The equilibrium adsorption data have been evaluated using Freundlich and Langmuir Isotherm models. The results illustrated that the adsorption follows Langmuir isotherm.

Heat-Resistant Fully Bio-Based Nanocomposite Blends Based on Poly(lactic acid)

Poly(lactic acid) (PLA) is melt mixed with polyamide 11 (PA11) to obtain a heat-resistant fully bio-based blend with PLA as the dominant component. The goal is achieved by adding small amounts of organoclay (OMMT), which is used to manipulate the blend microstructure. The selective positioning of the OMMT inside the PA11 and at the PLA/PA11 interface turns the blend morphology from drop/matrix into co-continuous at high PLA content (70 wt%). The OMMT-rich PA11 framework that interpenetrates the major PLA phase effectively contributes to bear stresses, and the nanocomposite blend keeps its structural integrity up to ≈160 °C, i.e., about 100 °C above the PLA glass transition.

Graft copolymerization of thiophene onto polystyrene synthesized via nitroxide-mediated polymerization and its polymer − clay nanocomposite

A new strategy for graft copolymerization of thiophene onto a polystyrene (PSt) backbone by a multi-step process is suggested and the effects of an organoclay on the final properties of the graft copolymer sample are described. For this purpose, first poly(styrene-co-4-chloromethyl styrene) [P(St-co-CMSt)] was synthesized via nitroxide-mediated polymerization. Afterwards, the chlorine groups of P(St-co-CMSt) were converted to thiophene groups using the Kumada cross-coupling reaction and thiophene-functionalized PSt multicenter macromonomer (ThPStM) was synthesized. The graft copolymerization of thiophene monomers onto PSt was initiated by oxidized thiophene groups in the PSt chains after addition of ferric chloride (FeCl3), an oxidative catalyst for polythiophene synthesis, and FeCl3-doped polythiophene was chemically grafted onto PSt chains via oxidation polymerization. The graft copolymer obtained was characterized by 1H NMR and Fourier transform infrared spectroscopy, and its electroactivity behavior was verified under cyclic voltammetric conditions. Finally, PSt-g-PTh/montmorillonite nanocomposite was prepared by a solution intercalation method. The level of dispersion of organoclay and the microstructure of the resulting nanocomposite were probed by means of XRD and transmission electron microscopy. It was found that the addition of only a small amount of organoclay (5 wt%) was enough to improve the thermal stabilities of the nanocomposite.© 2013 Society of Chemical Industry

Novel nanocomposites based on reactive organoclay of l-tyrosine and amine end-capped poly(amide–imide): Synthesis and characterization

In the present study, a series of nanocomposite materials were successfully prepared using a poly(amide–imide) (PAI) matrix and novel reactive organoclay as a reinforcing agent. The organoclay was synthesized from Cloisite Na+ and protonated form of l-tyrosine amino acid via ion-exchange reaction. It was confirmed by Fourier transform infrared spectroscopy, X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy and thermogravimetry analysis techniques. An optically active PAI was synthesized via solution polycondensation reaction of N,N′-(pyromellitoyl)-bis-phenylalanine diacid chloride and 4,4′-diaminodiphenylether. Then it was end-capped with amine end groups near the completion of the reaction to interact chemically with organoclay. Organoclay/PAI nanocomposite films containing different amounts of organoclay were prepared via solution intercalation method through blending of organoclay with the PAI solution. The nanostructures and properties of the organoclay/PAI hybrids were investigated using different techniques. Thermogravimetry analysis results indicated that the addition of organoclay into the PAI matrix increased the thermal decomposition temperatures of the resulting hybrid materials. The presence of amino acids as a biodegradable segment in both novel organoclay and optically active PAI, made the resulting nanostructure materials susceptible for biodegradation.

Synthesis and characterization of saturated polyester and nanocomposites derived from glycolyzed PET waste with varied compositions

Saturated polyester resin, derived from the glycolysis of polyethyleneterephthalate (PET) was examined as an effective way for PET recycling. The glycolyzed PET (GPET) was reacted with the mixture of phthalic anhydride and ethylene glycol (EG) with varied compositions and their reaction kinetic were studied. During polyesterification of GPET, acid and EG, the parameters like degree of polymerization (DP n ), extent of reaction (p) acid value and hydroxyl values were measured. The thermomechanical properties and the morphologies of the saturated polyester nanocomposites were examined by using a differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), wide angle X-ray diffraction (WAXRD) and transmission electron spectroscopy (TEM). There were significant differences observed in \({T}_{\textrm{g}}\), \({T}_{\textrm{m}}\) and \({T}_{\textrm{c}}\) before and after addition of GPET and clay content. Nanocomposites with lower content of organoclay showed intercalated morphology while by increasing the amount of organoclay, the exfoliated morphology was more prevalent. Water vapour transmission (WVT) was determined for saturated polyester nanocomposite sheets according to ASTM E96-80.

A Novel Type of Organo Clay Containing Alkyd-Melamine Formaldehyde Resins

In this study, organo clay-modified alkyd resins were synthesized and these modified alkyd resins were cured with different ratios of melamine formaldehyde resin for the first time. Alkyd resins were blended with 30% and 40% of a commercial melamine-formaldehyde resin. Alkyd-melamine formaldehyde resin films were cured at 140°C for 2 h in an oven. The effect of organo clay addition on the physical and chemical film properties was investigated. These surface coating properties of the resins enhanced with amount of organo clay up to 2–3%. These resins are suitable for manufacturing of high-performance industrial baking enamels.

Novel chiral poly(amide-imide) nanocomposites reinforced with silicate layers and TiO2 nanoparticles based on N-trimellitylimido-l-isoleucine

In the present investigation, the goal was the preparation, characterization, and surface morphology of poly(amide-imide)/TiO2/oganoclay nanocomposites. At first, an optically active poly(amide-imide) was synthesized from the polymerization reaction of N-trimellitylimido-l-isoleucine diacid with 4,4′-methylenebis(3-chloro-2,6-diethylaniline). The obtained polymer and TiO2 nanoparticles were used to prepare poly(amide-imide)/TiO2 nanocomposites through ultrasonic irradiation. Then, different amounts of organoclay were added to the poly(amide-imide)/TiO2 nanocomposite system to obtain poly(amide-imide)/TiO2/oganoclay nanocomposite. The resulting hybrids materials were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis techniques.

Organoclay/thermotropic liquid crystalline polymer nanocomposites. Part I: Effects of concentration on morphology, liquid crystallinity and thermal properties

AbstractThermotropic liquid crystalline polymer (TLCP) nanocomposites with different organoclay contents were prepared by a method combining ultrasonication, centrifugation and solution casting methods. The effects of organoclay concentration on morphology, liquid crystallinity and thermal properties of nanocomposites were characterized. Molecular level interactions existed in nanocomposites. With a small amount of organoclay (nominal 3.0 wt %), it was enough to change TLCP properties with enhanced thermal stability though with a small negative effect on liquid crystallinity. When high concentration organoclay was added, thermal stability decreased and liquid crystallinity lost with shearinduced phase separation occurrence.

Effects of the location of the nanoclay at the interface on the mechanical properties of a maleic anhydride grafted polypropylene/polyamide 6/organoclay co‐continuous blend

The effects of the location at the interface of an organoclay on the morphology and mechanical properties of a maleated‐polypropylene/polyamide 6 based co‐continuous blend have been studied. The organoclay is located at the interface because the level of interaction with each of the two polymers was similar. The dispersed particle size remained unchanged with organoclay content because the effect of viscosity and coalescence inhibition was offset by the surfactant compatibilization hindering. The Young's modulus remained constant; this behavior is mainly attributed to the inefficient orientation of the nanoclay. The ductility behavior suggests that there is a maximum amount of organoclay that can be located at the interface while retaining its ductile nature. Once this amount has been exceeded, the interface becomes saturated, and the dispersed particles become encapsulated. Encapsulation means that both an inorganic barrier and discontinuity appear, hindering the stress transmission through the interface and leading to fragility. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Physical and dyeing properties of poly(ethylene terephthalate)/montmorillonite nanocomposite filament yarns

AbstractThis research paper describes the generation of poly(ethylene terephthalate) (PET)/organoclay nanocomposite filaments by melt‐spinning method and investigation of their physical and dyeing properties. Two montmorillonite types of clay were modified using an intercalating agent synthesized and PET/organoclay (85/15 wt/wt) master batches were prepared using a corotating intermeshing twin screw extruder. Afterward, nanocomposite filaments containing different amounts of organoclay (0.5–5 wt%) were produced and dyed with two disperse dyes at atmospheric and high temperature dyeing conditions. Increased clay concentration led to reduced mechanical properties. Nonetheless, PET/organoclay nanocomposite filaments showed enhanced dyeability. POLYM. ENG. SCI., 2013. © Society of Plastics Engineers

Nanoclay modified with nonionic surfactants as reinforcement for styrene–butadiene rubber

In this study, the preparation of organobentonite using nonionic surfactants has been investigated. The organophilic clay has been characterized using Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction. The X-ray results suggest that the inter-gallery spacing of pristine clay increases with the incorporation of the surfactant where the nonionic surfactants intercalate into the interlamellar space of bentonite. The nanocomposites of SBR with various amounts of organoclay were prepared through the two roll mill. The X-ray diffraction peak observed for the modified clay also disappears in the rubber nanocomposites at low loading indicating exfoliation. Excellent improvement in mechanical properties, such as tensile strength, elongation at break and hardness, are observed on incorporation of the nanoclay. The results could be explained with the help of morphology, dispersion of the nanofiller and its interaction with the rubber. The formation of the intercalated nanocomposites was also indicated by scanning electron microscopy, used to study the surface morphology, which showed that the distribution of the organoclay in the polymer matrix was homogeneous. Thermal gravimetric analysis is also examined and the outcome of these results is discussed in this paper.