Role of Polymer Interactions with Clays and Modifiers on Nanomechanical Properties and Crystallinity in Polymer Clay Nanocomposites

Katti, Dinesh R.; Katti, Kalpana S.; Raviprasad, M.; Gu, Chunju

doi:10.1155/2012/341056

Cited by 21 publications

(19 citation statements)

References 51 publications

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“…Therefore, by mixing 2S protein with PVDF, this strong hydrophobic interaction could disturb the crystallization process of PVDF, inhibiting the formation of PVDF crystals. Similar results were reported previously . On the other hand, the increase in 2S content in PVDF/2S films favored the crystallization of PVDF.…”

Section: Resultssupporting

confidence: 91%

Modified dielectric properties of poly(vinylidene fluoride) via 2S fraction of soy protein

Zheng

2018

J of Applied Polymer Sci

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Soy protein, as a naturally available resource, has been widely studied as a functional material. Major 7S and 11S fractions of soy protein have drawn the most attention. In contrast, the 2S fraction, a component with low molecular weight, has rarely been explored in material applications. This study investigated the 2S fraction of soy protein as a functional modifier to tune the dielectric properties of poly(vinylidene fluoride) (PVDF). It is found that 2S protein could efficiently modify the crystallinity and crystal phases of PVDF, depending on the concentration of 2S protein. The variation of crystal structures and hydrophobic PVDF–2S interaction led to remarkably altered dielectric properties of PVDF/2S films, evaluated by both ferroelectric hysteresis and impedance analyses. Dielectric polarization of PVDF/2S films was enhanced as the concentration of 2S protein increased; meanwhile, high 2S protein content led to high hysteresis loss, which should be related to the increased electrical conductivity of PVDF/2S films. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46882.

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Section: Resultssupporting

confidence: 91%

Modified dielectric properties of poly(vinylidene fluoride) via 2S fraction of soy protein

Zheng

2018

J of Applied Polymer Sci

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“…2B that are associated with the adsorption of phenol appear in the lower frequency region at 755 cm −1 and 694 cm −1 and correspond to the out-of-plane C–H bending. 26 Similarly, a shoulder peak at 806 cm −1 , typical of the aromatic C–H bending region, indicates adsorption of phenol to the metal cation. 26-27 The sorption of phenol is further supported by the increase in the basal spacing observed from the XRD patterns ( cf.…”

Section: Resultsmentioning

confidence: 99%

Formation of environmentally persistent free radical (EPFR) in iron(iii) cation-exchanged smectite clay

Nwosu

Roy

Cruz

et al. 2016

Environ. Sci.: Processes Impacts

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Environmentally persistent free radicals (EPFRs) have been found at a number of Superfund sites, with EPFRs being formed via a proposed redox process at ambient environmental conditions. The possibility of such a redox process taking place at ambient environmental conditions is studied utilizing a surrogate soil system of phenol and iron(III)-exchanged calcium montmorillonite clay, Fe(III)CaM. Sorption of phenol by the Fe(III)CaM is demonstrated by Fourier-transformed infra-red (FT-IR) spectroscopy, as evidenced by the peaks between 1345 cm−1 and 1595 cm−1, and at lower frequencies between 694 cm−1 and 806 cm−1, as well as X-ray diffraction (XRD) spectroscopy, as shown by an increase in interlayer spacing within Fe(III)CaM. The formation and characterization of the EPFRs is determined by electron paramagnetic resonance (EPR) spectroscopy, showing phenoxyl-type radical with a g-factor of 2.0034 and ΔHp-p of 6.1 G at an average concentration of 7.5 × 1017 spins/g. EPFRs lifetime data are indicative of oxygen and water molecules being responsible for EPFR decay. The change in the oxidation state of the iron redox center is studied by X-ray absorption near-edge structure (XANES) spectroscopy, showing that 23% of the Fe(III) is reduced to Fe(II). X-ray photoemission spectroscopy (XPS) results confirm the XANES results. These findings, when combined with the EPFR concentration data, demonstrate that the stoichiometry of the EPFR formation under the conditions of this study is 1.5 × 10−2 spins/Fe(II) atom.

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“…In particular, the higher the positive charge of the atoms forming the functional groups, the higher is the interaction with the clay; on the contrary, a partial negative charge determines repulsions between the organic molecules and clay. According to their simulations, H and C atoms lead to attractive forces with clay, whereas other atoms (O and N) ensure repulsive forces ( Table S1 ) [ 26 ]. However, as simulated by Heinz et al, once the NH 2 group is protonated (-NH 3 + ), the situation changes, and repulsions become attractive forces instead, confirming the importance of environmental parameters such as pH for the molecule–clay interplay.…”

Section: Introductionmentioning

confidence: 99%

Changes in Optical Properties upon Dye–Clay Interaction: Experimental Evaluation and Applications

2021

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The development of hybrid materials with unique optical properties has been a challenge for the creation of high-performance composites. The improved photophysical and photochemical properties observed when fluorophores interact with clay minerals, as well as the accessibility and easy handling of such natural materials, make these nanocomposites attractive for designing novel optical hybrid materials. Here, we present a method of promoting this interaction by conjugating dyes with chitosan. The fluorescent properties of conjugated dye–montmorillonite (MMT) hybrids were similar to those of free dye–MMT hybrids. Moreover, we analyzed the relationship between the changes in optical properties of the dye interacting with clay and its structure and defined the physical and chemical mechanisms that take place upon dye–MMT interactions leading to the optical changes. Conjugation to chitosan additionally ensures stable adsorption on clay nanoplatelets due to the strong electrostatic interaction between chitosan and clay. This work thus provides a method to facilitate the design of solid-state hybrid nanomaterials relevant for potential applications in bioimaging, sensing and optical purposes.

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Role of Polymer Interactions with Clays and Modifiers on Nanomechanical Properties and Crystallinity in Polymer Clay Nanocomposites

Cited by 21 publications

References 51 publications

Modified dielectric properties of poly(vinylidene fluoride) via 2S fraction of soy protein

Modified dielectric properties of poly(vinylidene fluoride) via 2S fraction of soy protein

Formation of environmentally persistent free radical (EPFR) in iron(iii) cation-exchanged smectite clay

Changes in Optical Properties upon Dye–Clay Interaction: Experimental Evaluation and Applications

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