Organoclay Research Articles

Effect of expanded organoclay by stearic acid to curing, mechanical and swelling properties of natural rubber nanocomposites

The interlayer basal spacing of organoclay (OC) could be increased with stearic acid (SA) added, thus OC changed into expanded organoclay by SA (OCSA). The effect of various loadings of OCSA on the curing, mechanical and swelling properties of natural rubber (NR) nanocomposites were studied. The natural rubber/expanded organoclay (NR/OCSA) nanocomposites were prepared by melt intercalation using a laboratory open mill. The curing characteristics of NR compounds were determined using a Moving Die Rheometer (MDR). The X-ray Diffraction (XRD), Attenuated Total Reflectance Infrared (ATR-IR) Spectroscopy and Field Emission Scanning Electron Microscopy (FESEM) were used to study the dispersion of OCSA in the NR matrix. The mechanical properties of NR/OCSA nanocomposites such as tensile strength, elongation at break and hardness were determined using ISO standard and swelling of NR/OCSA nanocomposites in toluene were determined using ISO 1817. The results showed that the SA intercalated into the gallery of OC and reacted with the hydroxyl groups in OC. It was indicated with the shifting of the negative peak 1,700 to 1,723 cm-1 in the ATR-IR spectrum and increase the d-spacing of OC. The adding of various loadings of OCSA into NR could increase the torque and accelerate the curing of nanocomposites and it also could increase the mechanical and swelling properties of nanocomposites. The change in modulus at 100% elongation significantly increased with increasing the OCSA load until maximum loading at 10 phr. This trend was same with the hardness and modulus at 300% elongation. Meanwhile, the improvement of tensile strength and elongation at break was higher at 4 phr OCSA compared with the other loading. The increase of mechanical and swelling properties of NR/OCSA nanocomposites was due to intercalation/exfoliation of OCSA in NR matrix. It was revealed by appearing of the out-of-plane Si-O-(Al) stretch with peak value 1080 cm-1 in the ATR-IR spectrum and the peaks of OCSA in the XRD pattern was disappeared until the loading of OCSA 8 phr and the thickness of morphology of OCSA below 100 nm.

Effect of dendrimer modified montmorillonite on structure and properties of EPDM nanocomposites

The purpose of this work was to study the effect of dendrimer modified clay minerals on the structure and properties of ethylene-propylene-diene monomer (EPDM) nanocomposites.Flame-retardant and dendrimer modified organic montmorillonite (FR-DOMt) was successfully prepared by Na+-montmorillonite, tetrahydroxymethyl phosphonium chloride (THPC), N, N-dihydroxyl-3-aminomethyl propionate, and boric acid. This dendritic type of organoclay (OC) was used in preparation of EPDM/FR-DOMt nanocomposites. The properties of these nanocomposites were studied. The dispersion status of the layered silicates in EPDM was revealed by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD and TEM results showed that FR-DOMt was exfoliated in the EPDM matrix when 10 phr of FR-DOMt was incorporated. The mechanical behavior, thermal stability, and flame retardance of the samples were examined. The experimental data demonstrated that the EPDM hybrids owned an improved tensile strength and elongation at break. In addition, the nanocomposites exhibited higher thermal stability and flame retardance than that of unfilled EPDM matrix.

PLA/PBAT Bionanocomposites with Antimicrobial Natural Rosin for Green Packaging.

The use of biodegradable polymers is of great importance nowadays in many applications. Some of the most commonly used biopolymers are polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) due to their superior properties and availability. In this manuscript, we use a facile and green modification method of organoclay (OC) by antimicrobial natural rosin which is considered as a toxicity-free reinforcing material, thus keeping the green character of the material. It increases the interlayer spacing between the clay platelets. This was proven by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and found to impart antimicrobial properties to PLA/PBAT blends. The morphology of the resulting blends was conducted using scanning and transmission electron microscopies (SEM and TEM), and evidence of exfoliation and intercalation was observed. The thermal properties of the blends were studied using differential scanning calorimetry (DSC), and a detailed study of the crystallization of both PLA and PBAT was reported showing cold crystallization behavior of PLA. The final effect on mechanical and antimicrobial properties was also investigated. The obtained results reveal excellent possibility of using expanded OC modified PLA/PBAT polymer blends by adding a green material, antimicrobial natural rosin, for food packaging and biomembranes applications.

Rheological behavior and morphology of acrylonitrile-butadiene rubber/poly(ethylene-co-vinyl acetate) blends filled by various organoclay contents

The blends of acrylonitrile-butadiene rubber (NBR) and poly(ethylene-co-acetate) (EVA) with different mass ratios (20, 40 and 60 mass% NBR) and organoclay (OC) contents (1,3, 5 and 7 mass% OC) were prepared in an internal mixer. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results revealed that for the nanocomposites containing 7 mass% OC, the majority of OC layers were exfoliated although some intercalated structures could also be observed. The scanning electron micrographs of the nanocomposites containing 40 mass% NBR showed that the rubber average domain size decreased significantly with the increase in the OC content in comparison with that of the corresponding unfilled blend. Atomic force microscopy (AFM) images indicated that the addition of OC improved the mixing efficiency of the two parent polymers by which the two-phase morphology could not be detected to any further extent. The rheological experiments showed that percolation was taken place when the OC content was about 3 mass%. Moreover, the elasticity of the materials containing 3 mass% OC and beyond was much higher than that of NBR and its value increased with the increase in the OC content. These nanocomposites also had a plateau region in the entire range of angular frequency studied.

Functional organoclay with high thermal stability and its synergistic effect on intumescent flame retardant polypropylene

In this work a novel functional modifier for clay with increased thermal stability and synergistic effect on the flame retardancy of intumescent flame retardant polypropylene (IFR PP) composites was developed. First, triphenyl(undec-10-enyl)phosphonium bromide (TPB) was synthesized and characterized by FT-IR and 1H NMR spectroscopy. TPB has a high thermal stability with an initial decomposition temperature of about 270°C. Subsequently, TPB was used to prepare functional organoclay (OC) by cation exchange reaction. OC was characterized by thermogravimetric analysis (TGA) and wide-angle X-ray scattering (WAXS). The interlayer distance of novel OC increased to 1.85nm. OC was used in IFR PP nanocomposites prepared by melt mixing. The morphology, thermal stability and fire behavior of these IFR PP nanocomposites were investigated by SEM, TEM, TGA, limiting oxygen index (LOI), vertical burning test (UL94), and cone calorimeter (CC) test. In comparison to IFR (18wt%) PP composites, IFR (16wt%)+OC (2wt%) PP nanocomposites passed the UL94 V-0 rating and showed no dripping. The LOI value decreased from 30.5 to 28.8 due to the use of low molar mass TBP. It was shown by cone calorimeter tests that the additional used of 1 or 2wt% OC leads to a reduced heat release rate, smoke production rate and total smoke production. All these experimental results showed that this novel OC provided an excellent synergistic effect on the flame retardancy of IFR PP composites. Finally, electron beam treatment was used to enhance the thermal stability of flame retardant nanocomposites.

Hydraulic Performance of Organo Clay Enhanced Sand Bentonite as Secondary Liner

The leakage of petroleum from the storage tanks poses a serious threat to soil and groundwater. Hence an additional layer of impermeable material is usually provided as secondary containment systems in underground and above ground storage systems meant to store petroleum products. However the use of conventional mineral liner material is found to be ineffective for their use in secondary containment system to contain organic fluids. The conventional liner materials such as compacted sand–bentonite (SB) mixtures needs to be amended with materials of high organic sorption capacity. Therefore studies were carried out to assess the hydraulic performance of sand bentonite mixture amended with different percentages of organo clay (SOB) and to evaluate their possible use in secondary containment of petroleum product. The hydraulic conductivity of different SOB mixtures compacted at optimum conditions was evaluated with water and diesel as permeants. The coefficient of permeability was measured for various mixtures under different loads varying from 0 to 300 kPa. The permeability coefficient was evaluated both for loading and unloading cases. A decrease in the coefficient of permeability with diesel by an order of two, was observed on increasing the organo clay content from 0 to 10% in SB mix, where as a reverse trend was noted with water as permeant. The hydraulic performance of SOB mixture was found to be largely influenced by the proportion of organo clay, the nature of pore fluid and the applied pressure suggesting a need for careful proportion of mixture to be used as secondary liner.

Dissimilar Tendencies of Innovative Green Clay Organo-Modifier on the Final Properties of Poly(ε-caprolactone) Based Nanocomposites

Fil: Merino, Danila. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales; Argentina

Polymer/clay nanocomposites based on aliphatic–aromatic polyamide containing thiazole ring and new organomodified nanosilicate layers: Synthesis, characterization, and thermal properties study

New polyamide/clay nanocomposites (PACN) were produced using semicrystalline polyamide (PA) containing thiazole ring and new organoclay (OC) through solution intercalation technique. For further study, PA/Cloisite‐15A nanocomposites (PAAN) were also prepared using PA and Cloisite‐15A. X‐ray diffraction (XRD), field emission‐scanning electron microscopy (FE‐SEM), and transmission electron microscopy (TEM) results showed a good dispersion for OC in the PA matrix. A meaningful decrease in intensity of absorption from ultraviolet–visible spectra as well as from fluorescence emissions of resulted PACN were observed. As thermogravimetric analysis (TGA) in nitrogen atmospheres showed, the T5 and T10 increased by about 57% and 36%, respectively for PACN containing 5 mass% of OC, as the char yield enhanced greatly, which was about 16.3% higher than the neat PA. Also the TGA results showed that PACN had higher thermal stability than PAAN. Differential scanning calorimetry (DSC) analysis exhibited higher glass‐transition temperature values (Tg) for PACN as compared to the neat PA. POLYM. COMPOS., 39:E1407–E1420, 2018. © 2017 Society of Plastics Engineers

Preparation and characterization of an organo-palygorskite-Fe3O4 nanomaterial for removal of anionic dyes from wastewater

The organophilization of clays to increase interfacial interactions is a typical practice when the objective is its encapsulation with a polymer. This work intend to synthesize and characterize an organo-palygorskite-Fe3O4, to change the hydrophilicity of the material and investigate its efficiency in the removal of two anionic dyes from aqueous solution with the aim to use this material to treat wastewater contaminated with dyes. The organophilization of modified palygorskite–Fe3O4 was done with a cationic surfactant (cetyl trimethylammonium bromide, CTAB) and the material obtained was characterized by XRF, SEM, XRD, FTIR, Nano Zetasizer, density, BET surface area, TGA/DTA and contact angle measurements. XRF and FTIR confirmed the presence of carbon in the modified palygorskite–Fe3O4 nanoparticles while XRD showed new crystalline phases from CTAB. Furthermore, a positive zeta potential value appeared and an inversion in the nanoparticles' hydrophobicity happened due to the increase of organic carbon content in the organo-palygorskite-Fe3O4. The adsorbed anionic dye on organo-palygorskite-Fe3O4 may be completely recovered by the action of a magnet, showing an excellent adsorptive property and economical alternative adsorbents to treat dye wastewater. The negative values calculated for the free energies of adsorption indicate that the adsorption of methyl orange and indigo carmine on the active sites of organo-palygorskite-Fe3O4 surface was spontaneous and that the indigo carmine had the best interaction with the magnetic organo clay.

Evaluation of Chitosan /Organoclay Composite as Bone Tissue Engineering Scaffold

In this study, a scaffold composed of chitosan (C) and organoclay (OC) was prepared by utilizing freeze-drying method. The composition of resulting composite scaffold was evaluated using FTIR and SEM. The in vivo cytocompatibility of the composite was evaluated in vivo, by seeding MC3T3-E1 cells on composite scaffolds. In-vitro cell viability and proliferation were investigated using the MTT assay, while cell-scaffold constructs were evaluated using scanning electron microscopy. Preliminary in vivo experiments were also performed to evaluate tissue compatibility and ectopic bone-forming potential of C/OC composite scaffolds with MC3T3-E1 cells. The findings suggest that C/OC construct supported the proliferation of MC3T3-E1 cells, presented histobiocompatibility and promoted formation of calcified matrix. Based on the results, we conclude that the characterized C/OC composite system may have potential for use in bone tissue engineering applications. Keywords: Bone tissue engineering; Chitosan; Organoclay; Composite scaffold; Organically modified calcium-smectite DOI: 10.17350/HJSE19030000047 Full Text: Research Article

Influence of Chemical Additives on Shrinkage and Swelling Characteristics of Bentonite Clay

The montmorillonite clays were modified with Coco-amidopropylene betaine (CAPB) and Cetrimonium bromide (CTAB) having different alkyl chain lengths and also modified with Benzalkonium chloride (BKC) having a the benzyl substitute group had to reduce the swelling and shrinkage characteristics of montmorillonite clay. The modified organo clays were characterized by different analytical techniques. After knowing swelling and shrinkage characteristic of montmorillonite clay, it will be treated with three chemical admixtures i.e. Cocamidoproply betaine (CAPB), Benzalkoniumchloride (BKC), Cetrimonium bromide (CTAB) at different proportion i.e. 1%, 1% and 3% respectively. Those chemicals have a good potential for use in geotechnical applications with proper use of soil-chemistry interaction and its possible perceptions on clay surface in relation to moisture variation.

An experimental study on composite adhesives reinforced with different types of organo-clays

ABSTRACTIn this study, the mechanical properties of single lap joints prepared by adding nanoclays with different properties into adhesives with different characteristics (toughened, flexible, paste-type, and rigid) were experimentally investigated. Single lap joints and bulk specimens were produced using DP460, DP125, Araldite 2015, and AV138 as adhesives. High-concentration hydrocarbon-doped organo-clay (HDOC-1) obtained from Çankırı, low-concentration hydrocarbon-doped organo-clay (HDOC-2) obtained from Erzurum, and organo-clay (OC) were incorporated into the adhesives as reinforcements at two different concentrations (1% and 2% wt.). The aluminum alloy AA2024-T3 was used as the adherend material. Evaluation of experiment results showed that both the characteristics of the adhesive (toughened, flexible, paste-type, and rigid) and the different forms of clays significantly influenced failure loads of the joints. Moreover, increasing or decreasing the amount of clay added into the adhesive also affected failure loads of the joints; 1% wt. reinforcement provided the best results.

Clay-biosurfactant materials as functional drug delivery systems: Slowing down effect in the in vitro release of cinnamic acid

The main objectives of the present paper were the preparation and characterization of new surfactant-modified clays and the evaluation of their potential applicability as drug delivery systems for the oral administration of the cinnamic acid (CA) drug. The organoclays (OC) were prepared by loading different amounts of the biocompatible nonionic polyoxyethylene sorbitan monolaurate surfactant (Tween20) onto K10 montmorillonite (Mt) clay and characterized through the construction of the adsorption isotherms by means of the spectrophotometric method.The performance of the prepared material was verified by gathering the adsorption isotherms of the cinnamic acid onto the Mt/Tween20 organoclay and by monitoring the release profiles in both simulated gastric (SGF) and intestinal fluids (SIF).The quantitative analysis of the adsorption isotherms revealed that the uptake of the aromatic component onto both the blank and Tween20-loaded Mt was governed by positive cooperative processes and that the presence of the bio-surfactant enhanced the loading efficiency of the clay.By relating the raw montmorillonite uptake capability with that of the OC it was assessed that the presence of the bio-surfactant enhanced about 2 times the loading efficiency of the clay. From the XRD characterization of the obtained complexes, the successful intercalation of the drug into the prepared organoclay was demonstrated.Very useful information was obtained by the in vitro release studies, which showed that the release of the drug from both the clay and organoclay was prolonged in comparison with the pharmacokinetics of the free drug. Besides, the intercalation of the surfactant into the nano-carrier ensured the complete release of the CA after oral drug administration and the kinetics of the release process was strongly dependent on the type of drug formulation used, which means that the CA release can be modulated by properly functionalizing the clay surface.

Comparative Properties of Styrene-Butadiene Rubbers (SBR) Containing Pyrolytic Carbon Black, Conventional Carbon Black, and Organoclay

ABSTRACTTo evaluate the reinforcing potential of pyrolytic carbon black, styrene-butadiene rubber (SBR) was filled with pelletized pyrolytic carbon black (pCBp), N660 industrial CB, their blend in a 1/1 ratio, and the latter also in the absence and presence of additional organoclay (OC). The Shore A hardness of the filled SBR gums was 65 ± 2°. Effects of the compositions on the filler dispersion, cure behavior, dynamic mechanical thermal parameters (including the Payne effect), tensile mechanical (including the Mullins effect), and fracture mechanical (making use of the J-integral concept) properties were studied and discussed. Though pCBp had a higher specific surface weight than CB, the latter proved to be a more active filler with respect to the tensile strength. The opposite tendency was found for the tear strength and fracture mechanics characteristics (J-integral at crack tip opening, tearing modulus, and trouser tear strength). This was traced to an enlargement in the crack tip damage zone supported by the dispersion characteristics of the pCBp. The performance of pCBp was similar to that of CB with respect to some other properties. OC supported the filler networking which positively affected the resistance to crack initiation.

Crystallization, structural and mechanical properties of PA6/PC/NBR ternary blends: effect of NBR-g-GMA compatibilizer and organoclay

Abstract Ternary blends based on polyamide 6 (PA6)/acrylonitrile-butadiene rubber (NBR)/polycarbonate (PC) were prepared by melt compounding via extrusion process. The effect of organoclay (OC), compatibilizer, and blend ratio was investigated on structural and mechanical properties of the blend. The effect of OC and compatibilizer studied on crystallization temperature, melting temperature, and crystallinity of PA6/NBR/PC ternary blends was studied by differential scanning calorimetry. Improvement in the crystal structure of compatibilized blend compared to unfilled blend was observed by polarized optical microscope. Dispersion of OC into PA6/NBR/PC ternary blends was done by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy (SEM)/energy-dispersive X-ray. The results confirmed the exfoliation of OC particles into the polymer matrix. The improvement in yield stress and tensile modulus of the ternary blend was observed in the presence of OC. The impact strength showed an increase using NBR-glycidyl methacrylate-grafted (g-GMA) to prepare compatibilized PA6/NBR/PC ternary blend.

Study on the morphology, static and dynamic mechanical properties of (styrene butadiene rubber/ethylene propylene diene monomer/organoclay) nanocomposites vulcanized by the gamma radiation

ABSTRACTBlends of styrene‐butadiene rubber/ethylene–propylene‐diene monomer (SBR/EPDM) with and without organoclay (OC) were prepared by melt mixing method. Then the samples were vulcanized by gamma radiation in comparison to conventional sulfur curing system. Characterization by X‐ray diffraction analysis, atomic force microscopy, and Field emission scanning electron microscopy revealed the intercalation structure and good dispersion of the OC in prepared nanocomposites. In addition to this, by increasing the absorbed dose of radiation and using OC, reduction in solvent uptake, increase in crosslink density and improvement of mechanical and dynamic–mechanical properties were observed. Comparison of the tensile strength of irradiated nanocomposite with the sulfur cured one's displayed the synergistic effect of the OC and gamma radiation on tensile properties of SBR/EPDM blend. Mooney–Rivlin plot confirmed the increase in crosslink density and interaction between rubbers due to presence of OC and increasing absorbed dose. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43581.

Natural Pyrethrum Extracts Photo-stabilized with Organo Clays

Natural Pyrethrum Extracts Photo-stabilized with Organo Clays

Raw rubber and viscoelastic properties of organoclay filled latex crepe rubber

Organoclay (OC) filled natural rubber (NR) latex crepe was prepared in view of investigating the effect of organoclay on raw rubber properties and viscoelastic properties by incorporating aqueous dispersion of OC clay into NR latex followed by conventional acid coagulation procedure. Raw rubber properties of OC filled fractionated bleached (FB) and unfractionated unbleached (UFUB) crepe rubber were evaluated to characterized the composite samples in comparison to standard crepe rubber whilst process based characterization was carried out with Moony viscosity and Mooney relaxation data. Raw rubber properties have shown that OC acts as a pro-oxidant and as a result, Initial Plasticity (Po) and Plasticity Retention Index (PRI) which measures the thermo-oxidative degradation were negatively affected. Viscoelastic behaviour, as measured with low shear strain rate flow properties, is significantly affected by the addition of OC into the NR latex. Reduction of Mooney viscosity of OC filled crepe rubber has been explained with thermal oxidation as a result of metal impurities in the OC and plasticization caused by the organic modifier of the OC. Mooney stress relaxation has shown that lower clay loading provides a better processability and dispersion of OC within the crepe rubber.

Thermal and morphological studies of poly(vinyl alcohol)/poly(vinyl pyrrolidone)/organoclay nanocomposites containing L-leucine moiety

This work is devoted to the synthesis and characterization of poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP)/organoclay (OC) (PPOC) hybrid and comparison between PPOC, PVA/PVP matrix, and PVA/OC (POC) nanocomposite (NC). The PPOC NCs were prepared by mixing a colloidal swelled solution consisting of OC with a water solution of PVA and PVP in the 3:1 weight ratio of PVA to PVP. L-Leucine ammonium ion-exchanged clay was utilized as the nanofiller. The obtained NCs were characterized by Fourier transform infrared, X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, and transmission electron microscopy. The morphological studies indicate that the flake structured OC is rather homogeneously dispersed in host matrix. The PPOC NCs exhibited improved thermal stability compared with pure polymers and POC NC. The improvement of thermal properties was attributed to the homogeneous and good dispersion of OC in the polymeric matrix and the strong hydrogen bonding between O–H of PVA, C = O of PVP, and Si–O of OC.

Discussion on: An accurate, quick and simple method to determine the plastic limit and consistency changes in all types of clay and soil: The thread bending test. Moreno-Maroto, J. M. and Alonso-Azcarate, J. Applied Clay Science. 114, 497–508. By G. E. Barnes

The organophilization of clays to increase interfacial interactions is a typical practice when the objective is its encapsulation with a polymer. This work intend to synthesize and characterize an organo-palygorskite-Fe3O4, to change the hydrophilicity of the material and investigate its efficiency in the removal of two anionic dyes from aqueous solution with the aim to use this material to treat wastewater contaminated with dyes. The organophilization of modified palygorskite–Fe3O4 was done with a cationic surfactant (cetyl trimethylammonium bromide, CTAB) and the material obtained was characterized by XRF, SEM, XRD, FTIR, Nano Zetasizer, density, BET surface area, TGA/DTA and contact angle measurements. XRF and FTIR confirmed the presence of carbon in the modified palygorskite–Fe3O4 nanoparticles while XRD showed new crystalline phases from CTAB. Furthermore, a positive zeta potential value appeared and an inversion in the nanoparticles' hydrophobicity happened due to the increase of organic carbon content in the organo-palygorskite-Fe3O4. The adsorbed anionic dye on organo-palygorskite-Fe3O4 may be completely recovered by the action of a magnet, showing an excellent adsorptive property and economical alternative adsorbents to treat dye wastewater. The negative values calculated for the free energies of adsorption indicate that the adsorption of methyl orange and indigo carmine on the active sites of organo-palygorskite-Fe3O4 surface was spontaneous and that the indigo carmine had the best interaction with the magnetic organo clay.