Synthesis and characterization of an exfoliated modified syndiotactic polystyrene/Mg–Al-layered double-hydroxide nanocomposite

Jaymand, Mehdi

doi:10.1038/pj.2010.127

Cited by 34 publications

(28 citation statements)

References 35 publications

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“…Relative to the behavior observed with the homopolymer, the crystallizable copolymer usually exhibits a low melting temperature, low degree of crystallinity and a significant decrease in the overall rate of crystallization. 13,34 The T g data also help in understanding the effects of constituent groups on the movement of polymer chains. It is clear from Figure 9 that the T m and T g values of the modified polymers depend on the graft copolymerization.…”

Section: Characterization Of Graft Copolymermentioning

confidence: 99%

“…In some cases, a disordered immiscible system is obtained, which also shows no peaks; hence, the absence of an XRD peak cannot be taken as definitive evidence of the formation of an exfoliated nanocomposite, and additional evidence, usually TEM images, is required. 13,43 The XRD patterns of the sPS-g-PMMA/ MMT nanocomposite in the range of 2y¼2-251 is shown in Figure 7. For the nanocomposite, no peaks are observed, which could mean that either an exfoliated or an immiscible nanocomposite has been formed.…”

Section: Characterization Of Graft Copolymermentioning

confidence: 99%

“…The chemical structure of the graft copolymer was further examined by 13 C-NMR. The 13 C-NMR spectrum of the sPS-g-PMMA (Figure 4b) shows all of the peaks corresponding to carbon atoms in different environments in the copolymer structure.…”

Section: Characterization Of Graft Copolymermentioning

confidence: 99%

“…[10][11][12] Methods typically used to prepare polymer-layered inorganic nanocomposites involve the incorporation of a layered silicate into a solvent-swollen polymer (solution blending) or polymer melt (melt blending) or by addition of a modified silicate to a polymerization reaction (in situ method). [13][14][15][16][17][18] A small weight percent of layered silicates that are properly dispersed throughout the polymer matrix thus create a much higher surface area for polymer/filler interactions than conventional composites can. Depending on the strength of the interfacial interactions between the polymer matrix and the layered silicate, three different types of polymer/layered silicate nanocomposites are thermodynamically achievable.…”

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confidence: 99%

“…40,41 In our previous studies, we investigated the synthesis and characterization of a syndiotactic polystyrene-grafte-[polystyrene-block-poly (p-methylstyrene)]/MgAl-layered double-hydroxide nanocomposite using polymer intercalation from the solution into the MgAl-layered double hydroxide. 13 At least two important factors need to be considered to achieve the homogeneous dispersion of the clay or layered double hydroxide layers in the sPS or its graft copolymer hybrids. First, the surfactant should be intercalated between the silicate layers of the clay by ionic bonding.…”

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Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

Jaymand

2011

Polym J

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This study aims to explore an effective route for the graft copolymerization of methyl methacrylate (MMA) monomer onto syndiotactic polystyrene (sPS) using free-radical polymerization, and the effects of an organophilic montmorillonite on the final properties of graft copolymer samples. For this purpose, the chlorine groups of a-phenyl-chloro-acetylated sPS were converted to 9-decen-1-oxy groups by a substitution nucleophilic reaction in the presence of a solvent composed of 9-decen-1-ol moiety, sodium hydride (NaH) and dry N,N-dimethylformamide. The vinyl-terminated sPS multicenter macromonomer (VsPSM) obtained was used in free-radical copolymerization with MMA monomer in a heterogeneous process to yield a graft copolymer (sPS-graftpoly(methyl methacrylate) (sPS-g-PMMA)). The structure of VsPSM and sPS-g-PMMA were determined by 1 H nuclear magnetic resonance and Fourier transform infrared spectroscopy. Thereafter, organophilic MMT was obtained after being treated with hexadecyl trimethyl ammonium chloride salt by an ion-exchange process. Finally, the sPS-g-PMMA/MMT nanocomposite was prepared by a solution intercalation method. X-ray diffraction and transmission electron microscopy were used to confirm nanocomposite formation. It was found that the addition of only a small amount of organoclay (3 wt%) was enough to improve the thermal stabilities and properties of the nanocomposite. Polymer Journal (2011) 43, 901-908; doi:10.1038/pj.2011.79; published online 7 September 2011Keywords: free-radical polymerization; graft copolymer; macromonomer; montmorillonite; nanocomposite; poly(methyl methacrylate); syndiotactic polystyrene INTRODUCTION Nanocomposites are defined as materials in which the particle size of the dispersed phase is in the nanometer range in at least one dimension. Organic-inorganic hybrids based on layered inorganic compounds, such as clays and organic polymers, have been studied because of their exceptional properties, such as increased modulus, strength, reduced gas permeability and enhanced thermal stability. [1][2][3][4][5] The dispersion of the silicate layers in the polymer matrix is improved by replacing the metal cations in the clay (such as sodium MMT; Na + -MMT) with ions bearing an aliphatic chain to compatibilize the silicate. This compatibilization enhances the silicate's interaction with the polymer by enlarging the interlayer, and the compatibilized clay is known as an organoclay. [6][7][8][9] Although complete compatibility between the long aliphatic chain of the organic modifier and the polymer matrix may be desirable for better dispersion of the clay, it appears that the modification of the clay by the introduction of surfactants to obtain better compatibility is less important than the modification of the polymer matrix by the introduction of polar groups. Polymers containing polar groups capable of associative interactions, such as Lewis acid/base interactions or hydrogen bonding, lead to intercalation of polymer chains in the silicate layers. To improve the polarizability or hy...

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Section: Characterization Of Graft Copolymermentioning

confidence: 99%

Section: Characterization Of Graft Copolymermentioning

confidence: 99%

Section: Characterization Of Graft Copolymermentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

Jaymand

2011

Polym J

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Polymer Nanocomposites Based on Nano Magnesium Hydroxide

Zhang,

Wu,

Zhang

et al. 2024

Chemical Physics of Polymer Nanocomposites

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Discretization and Encapsulation of Palladium inside the Cavity of Crown Ether within the Interlayer of Layered Double Hydroxide for Enhanced Activity: A Case Study with Hydrogenation Reaction

Ravuru

Jana

2022

Adv Materials Inter

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interactions of the catalytic nanoparticles resulting in unsatisfactory performance. [2] In an attempt to overcome the above shortcomings, noble metals were doped through self-assembly and layer by layer configuration on layered sheets of 2D materials (graphene sheets, MoS 2 , reduced graphene oxide, dichalcogenides, etc.) having high charge density and surface to volume ratio. [3][4][5][6] Additionally, the synthesis of these materials is chemical intensive and needs high temperature making the catalyst preparation unfavorable in terms of economic and energy considerations. Thus, the research focus in catalysis is now shifted to tailoring the geometry, electronic configuration, and charge density of the active metal. [7] Several ternary heterojunction compounds, complex and sandwiched geometry-based materials were synthesized to bridge the above-mentioned research gaps. However, a potential catalyst has less structural hindrance and better performance. Therefore, research on single-atom catalysis has gained attention due to the reason that the activity and stability of the catalysts attain the maximum when the size and distribution of the active metal approach the limit of a single atom. Another way to augment the performance and overcome the above limitations is by discretizing the active sites inside the ligand cavities. [8][9][10][11][12] Such flexibility regulates the local atomic arrangement controlling the surface properties easily.Anionic clays, like, layered double hydroxides (LDHs)where M 2+ is a divalent metal ion, M 3+ is a trivalent metal ion, and A n− is an n-valent anion) having exchangeable interlayer anions are suitable candidates as support materials that can be tuned to host the active metal in the interlayer. [13] LDHs are categorized under layered materials having positive lattice charge with intercalated anions, like, CO 3 2− , SO 4 2− , F − , OH − , NO 3 − , Cl − with basal spacing 0.7-0.88 nm. Additional features, like, high surface to volume ratio and charge density make the system versatile for such catalysis applications. Due to the structural heterogeneity, their applications include degradation of pharmaceutical components, organics, methanol oxidation reaction, oxygen evolution reactions, etc. [14][15][16] To enhance the activity of theseThe activity of the noble metal-based heterogeneous catalysts is limited by weak metal-support interactions, aggregation, and low surface to volume (S/V) ratio. The activity can be augmented in many ways. Among them, the discretization of the active sites and redistribution of electron density around the metal atom is an important one. In this work, these two phenomena are studied concerning a model reaction, hydrogenation of p-nitrophenol (p-NP). Herein, 1,4,7,10,13-pentaoxacyclopentadecane ether is introduced in the basal space of layered double hydroxide (LDH) to encapsulate noble Pd0 atom inside the cavity of the crown molecule strategically. The modified LDH (Pda-ECC-L0.10@in situ CoAl LDH) augments the properties, like, high S/V ratio and nonag...

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Synthesis and characterization of an exfoliated modified syndiotactic polystyrene/Mg–Al-layered double-hydroxide nanocomposite

Cited by 34 publications

References 35 publications

Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

Polymer Nanocomposites Based on Nano Magnesium Hydroxide

Discretization and Encapsulation of Palladium inside the Cavity of Crown Ether within the Interlayer of Layered Double Hydroxide for Enhanced Activity: A Case Study with Hydrogenation Reaction

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