Incorporation Of Layered Silicates Research Articles

Synergistic enhancement of rheological and anti-aging properties of asphalt modified with bio-oil and layered silicate

Applying bio-oil to asphalt pavement effectively reduces the dependence on traditional petroleum asphalt in pavement industry. However, the utilization of bio-oil can encounter rutting and aging issue of modified asphalt. To solve the aforementioned issue, two kinds of organic layered silicates with typical structures were adopted to enhance the high-temperature and anti-aging performance of the bio-modified asphalt. The modification mechanism and the synergistic effect of bio-oil and organic layered silicate on asphalt were explored through rheological characterization, infrared spectroscopy tests, gel chromatography tests, etc. Results showed that the incorporation of layered silicate in bio-modified asphalt can improve asphalt-filler interaction and hence the high-temperature and fatigue performance of asphalt. When the content of layered silicate is 5 %, the negative effect of Castor oil on the high-temperature performance of asphalt can be eliminated. Still, for Turpentine wood oil and Straw oil, the content of layered silicate is 7 %, which shows the same effect. The waste bio-oils can balance the low-temperature performance of asphalt modified with layered silicates. Furthermore, the addition of layered silicates was effective to reduce oxidation reaction and improve the anti-aging performance of bio-oil modified asphalt. When the ratio of layered silicate to bio-oil is 1 1, the composite-modified asphalt maintains the best anti-aging performance. Specifically, Castor oil, Straw oil, and OMMT are more suitable, and Turpentine wood oil and OREC are more appropriate. According to the quantification of the functional group aging index, the SI and CI of the optimal ratio of different types of bio-oil asphalt are Castor oil: 61.64 % and 59.41 %, Turpentine wood oil: 50.02 % and 53.57 %, Straw oil: 50.01 % and 55.05 %. Composite modified asphalt can be applied to complex service conditions.

Interfacial In Situ Polymerization of Layered-Silicate/Poly (Hexamethylene Isophthalamide) Nanocomposites

In this work Poly (hexamethylene isophthalamide) (PA 6I) was synthesized via interface step polymerization at room temperature for the first time, here. Layered silicates were used in order to fabricate PA 6I nanocomposites by in-situ polymerization. Thermal, mechanical and morphological of obtained nanocomposites were examined. The dispersion effect of silicate layers in the matrix was studied by means of XRD and FE-SEM. The incorporation of layered silicates in PA 6I leads to a significant improvement in the mechanical properties of the resulting nanocomposites. The thermogravimetric analysis results showed that layered silicate incorporation enhances the thermal resistance of PA 6I nanocomposites. Improvements in thermal degradation properties, while Young’s moduli have also been modified.

Thermal and Nanoindentation Behaviours of Layered Silicate Reinforced Recycled GF-12 Nanocomposites

<p class="1Body">This work is an attempt to improve the thermal and nanoindentation behaviours of recycled Glass-Filled Polyamide-12 (GF-12) by adding layered Silicate (Nanoclay) as a reinforced filler. Differential Scanning Calorimetry (DSC) and Nanoindentation tests were conducted to study the effect of various loading levels (0-7 wt. %) of Nano-layered silicate on the thermal and nanohardness behaviours of GF-12 and its nanocomposites. Wide Angle X-ray Diffraction (WAXD) was employed to characterise the nanostructure of material and determine the intercalation/exfoliation for layered silicate in a GF-12 matrix. This study reveals that the layer silicate has a positive effect on the hardness results. Nanoindentation results showed remarkable improvement when layered silicate was added to recycled GF-12. The Glass transition (T<sub>g</sub>) and crystallization (T<sub>c</sub>) temperatures showed a slight improvement over the base polymer by the incorporation of layered silicate. Moreover, the enhancement of crystallization was obvious with the addition of clay loading, which functioned as a nucleating agent that could increase the rate of crystallization.</p>

Enhanced Specific Capacitance of Self-Assembled Three-Dimensional Carbon Nanotube/Layered Silicate/Polyaniline Hybrid Sandwiched Nanocomposite for Supercapacitor Applications

Platelike montmorillonite (known as nanoclay), with ∼1 nm thick aluminosilicate layers, is the most common layered silicate used because of its availability and environment-friendly nature. With the increasing demand for cheaper and eco-friendly materials for energy storage applications, these layered silicates could be explored as a suitable candidate. In this work, a series of self-assembled three-dimensional electrode materials for supercapacitors have been synthesized from carbon nanotubes (CNTs), Cloisite 30B, and polyaniline (PANI) by both in situ and ex situ approaches. The role of the layered silicate in the electrochemical performance of these electrode materials has been explored. Morphological studies revealed the successful coating of PANI over the CNTs and silicate layers of the Cloisite 30B and the development of a self-assembled three-dimensional porous sandwichlike structure. With the incorporation of layered silicate, the morphology was observed to be highly porous with an enhanced electr...

Improved mechanical and corrosion properties of nickel composite coatings by incorporation of layered silicates

Layered silicates as exfoliated montmorillonite are incorporated into nickel films by electrodeposition, enhancing both corrosion resistance and hardness. Films were deposited onto stainless steel from a plating solution adjusted to pH 9 containing nickel sulfate, sodium citrate, and various concentrations of exfoliated montmorillonite. The presence of the incorporated layered silicate was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composite films were also compact and smooth like the pure nickel films deposited under the same conditions as shown by scanning electron microscopy. X-ray diffraction results showed that incorporation of layered silicates into the film do not affect the nickel crystalline fcc structure. The nanocomposite films exhibited improved stability and adhesion. Pure nickel films cracked and peeled from the substrate when immersed in 3.5% NaCl solution within 5 days, while the nanocomposite films remained attached even after 25 days. The corrosion resistance of the nickel nanocomposites was also improved compared to nickel films. Nickel-layered silicate composites showed a 25% increase in Young's modulus and a 20% increase in hardness over pure nickel films.

Water Absorption Behavior, Mechanical and Thermal Properties of Vinyl Ester Matrix Nanocomposites Based on Layered Silicate

The water absorption behavior, mechanical and thermal properties of vinyl ester matrix nanocomposites based on layered silicate were investigated. To characterize interlaminar structure of the nanocomposites, XRD, SEM, EDS, and TEM were performed. The mechanical and thermal properties of neat sample were improved by the incorporation of layered silicate. The improvement of the water repellence behavior was observed for the nanocomposites. The hardness and elastic moduli after water absorption was reduced due to the effect of water molecules entering into the polymer chains. However, the higher amount of clay reinforcement led to less reduction in hardness since the barrier properties.

Morphology and Thermal Properties of Renewable Resource-Based Polymer Blend Nanocomposites Influenced by a Reactive Compatibilizer

Partially miscible blends of poly(lactic acid) (PLA) and poly(hydroxybutyrate) (PHB) have been prepared by the melt mixing method. An interpenetrating network structure created by a maleic anhydride (MA) compatibilizer imparted additional interactions between the two matrices, which has resulted in increased miscibility within the blends. A modified interface has been characterized using morphological analysis through FT-IR and SEM analysis. Because MA compatibilization distributed flexible intermolecular hydrogen bonding within the blend matrix, elongation at break and Izod impact strength has been reported at a maximum of 540.17% and 99%, respectively, compared to those of the PLA matrix. Further, incorporation of layered silicates within the optimized composition of the PLA/PHB/MA blend modified the tensile strength by 49%, without compromising its superior flexible characteristics. Simultaneously, the renowned thermal insulating property of exfoliated/intercalated layered silicate works well to promot...

Adapting wood hydrolysate barriers to high humidity conditions

The incorporation of layered silicates in bio-based barrier films resulted in lower water vapor permeability, and significantly lowered oxygen permeability at a relative humidity (RH) as high as 80%, with reduced moisture sensitivity of the wood hydrolysate (WH) based films. The applicability of WH based films was accordingly extended over a wider relative humidity condition range. Crude aqueous process liquor, the WH, was extracted from hardwood and utilized as a feed-stock for films without any upgrading pretreatment, yet producing superior oxygen barrier performance compared to partially upgraded WH and highly purified hemicelluloses. Films composed of crude WH and either one of two types of naturally occurring layered silicates, montmorillonite (MMT) or talc, as mineral additives, were evaluated with respect to oxygen and water vapor permeability, morphological, tensile and dynamic thermo-mechanical properties. Films with an oxygen permeability as low as 1.5 (cm3μm)/(m2daykPa) at 80% RH was achieved.

Thermal properties and flammability of polylactide nanocomposites with aluminum trihydrate and organoclay

Abstract Biodegradable polylactide (PLA) nanocomposites with aluminum trihydrate (ATH) and modified montmorillonite (MMT) were prepared via direct melt compounding using a twin-screw micro extruder. The exfoliated and intercalated structures of clay in the matrix were observed by TEM and XRD. The thermal oxidative degradation temperature and activation energy of the PLA/ATH/MMT nanocomposite determined by thermogravimetric analysis are higher than that without addition of ATH and organoclay. The incorporation of layered silicates into the PLA/ATH composite results in further stabilization throughout the degradation step. The V-0 rating (UL94 V) of the PLA nanocomposite has been achieved, and the melt dripping was reduced during combustion. Results showed that high loading of the conventional flame retardant ATH yielded brittle PLA composites; however, replacing a portion of the ATH with modified MMT in the PLA matrix improved this result.

Effect of layered silicate reinforcement on the structure and mechanical properties of spent polyamide-12 nanocomposites

The aim of this work was to study the structure and mechanical properties of spent polyamide-12 and spent polyamide-12/layered silicate reinforced novel nanocomposites. Layered silicate at 1, 3, 5 and 7wt.% was incorporated in spent polyamide-12 and its nanocomposites were prepared using single screw injection moulding technique. The interlamellar structure and surface morphology were characterised by transmission electron microscope (TEM) and scanning electron microscope (SEM). Different levels of layered silicate dispersion (as characterised by TEM and SEM) correlated strongly with improvements in mechanical performance. The results showed that the tensile and flexural properties are found to be increased with the incorporation of layered silicate into spent PA-12 matrix. Comparison of tensile and flexural test results between virgin PA-12, spent PA-12 and spent PA-12 nanocomposites showed that spent PA-12 samples have retained 70% of its tensile and 80% of its flexural properties respectively, compared to virgin PA-12.

Emerging biodegradable materials: starch- and protein-based bio-nanocomposites

This article provides a broad overview on the natural polymer-based bio-nanocomposite properties, processing and application. Bio-nanocomposites prepared with natural biopolymers, such as starch and protein, can be formed using a melt intercalation or a solvent intercalation method. Incorporation of layered silicates into the biopolymer matrices results in improved mechanical properties, water vapor barrier properties, and thermal stability of the resulting bio-nanocomposites without sacrificing biodegradability due to their nanometer size dispersion. Consequently, even though natural polymer-based bio-nanocomposite is in its infancy, it has a huge potential in the future.

Poly (1-Butene)/Clay Nanocomposites: A Crystallization Study

Nanocomposites of poly (1-butene) (PB)/clay were prepared by melt intercalation. Organically modified clay was used to facilitate the melt intercalation. The effect of modified layered silicate on crystallization, spherulitic structures and polymorphism of PB was investigated. Isothermal crystallization studies clearly indicate enhancement in crystallization rate by the clay. Incorporation of layered silicate in the polymer disturbs the spherulitic morphology as evidenced by optical microscopy. The crystallization of PB in the presence of layered silicates occurs in form II, similar to pristine PB. However, the phase transformation studies reveal that the phase transformation from form II to form I at room temperature takes place faster in the case of PB nanocomposites.

Morphology, thermal relaxations and mechanical properties of layered silicate nanocomposites based upon high-functionality epoxy resins

This paper investigates the possibility of improving the mechanical properties of high-functionality epoxy resins through dispersion of octadecyl ammonium ion-modified layered silicates within the polymer matrix. The different resins used are bifunctional diglycidyl ether of bisphenol-A (DGEBA), trifunctional triglycidyl p-amino phenol (TGAP) and tetrafunctional tetraglycidyldiamino diphenylmethane (TGDDM). All resins are cured with diethyltoluene diamine (DETDA). The morphology of the final, cured material was probed by wide-angle X-ray scattering, as well as optical and atomic force microscopy. The α- and β-relaxation temperatures of the cured systems were determined using dynamic mechanical thermal analysis. It was found that the presence of organoclay steadily decreased both transition temperatures with increasing filler concentration. Further, the effect of different concentrations of the alkyl ammonium-modified layered silicate on the toughness and stiffness of the different epoxy resins was analyzed. All resin systems have shown improvement in both toughness and stiffness of the materials through the incorporation of layered silicates, despite the fact that it is often found that these two properties cannot be simultaneously achieved.

Polymer Crystallization Studied in Confined Dimensions using Nanocomposites from Polymers and Layered Minerals

ABSTRACTPolymer-layered silicate nanocomposites from polyamide-11 (PA-11) were prepared and the morphology and properties have been investigated in order to link the fundamental research field of polymer crystallization with the technical important field of composite materials. Semi-crystalline polymers are known to crystallize in different phases (e. g. monoclinic, hexagonal) forming chain-folded lamellar crystals. Depending on experimental conditions (e. g. temperature, pressure) the crystal size (lamellar thickness) affects the stability of these phases. The incorporation of layered silicates acting as hard walls into semi-crystalline polymers opens new possibilities to: i) study polymer crystallization in confined dimensions, and ii) provide materials from commodity or engineering polymers with enhanced properties. The effect of an external confinement introduced by highly anisotropic silicate layers of organically modified clay minerals on crystal growth and nanocomposite properties has been studied. The composites are prepared by in situ polycondensation of polyamides and/or blending via melt extrusion. The nanocomposites exhibit a homogeneous distribution of individual silicate layers at low clay contents. The lamellar thickening growth is reduced in polyamide crystallization due to the external constrained of the silicate layers in the host polymer. Furthermore these nanocomposites show a slightly enhanced thermal stability, tensile modulus and an increased elastic behavior over a broader temperature range. No distinct glass transition has been observed at highest clay contents.