Relaxation phenomena in poly(vinyl alcohol)/fumed silica affected by interfacial water

Gun'ko, V.М.; Pissis, P.; Spanoudaki, Anna; Zarko, V.I.; Nychiporuk, Y.M.; Andriyko, L.S.; Goncharuk, E.V.; Лебода, Р.; Skubiszewska–Zięba, J.; Osovskii, V.D.; Ptushinskii, Yu.G.

doi:10.1016/j.jcis.2007.03.065

Cited by 24 publications

(11 citation statements)

References 56 publications

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“…In these materials, the PEG‐graphene layers are important for accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates, and rendering the sulfur particles electrically conducting. Notice that a PEG interfacial layer can be less dense than poly(vinyl alcohol), PVA, because the latter can form strong hydrogen PVA–PVA bonds 30–33. Previous comparative investigations of PEG‐Al 2 O 3 /SiO 2 /TiO 2 and A‐300‐PEG composites showed34 that local interactions between polymer and AST are stronger than that of polymer–polymer.…”

Section: Introductionmentioning

confidence: 99%

Thermal and dielectric studies of PEG/C/AST nanocomposites

Klonos

Kaprinis

Zarko

et al. 2012

J of Applied Polymer Sci

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C/AST/PEG nanocomposites with fumed AST (89 wt % Al 2 O 3 , 10 wt % SiO 2 , 1 wt % TiO 2 ), activated carbon, and poly(ethylene glycol), PEG, were prepared in a wide range of PEG and C/AST (1 : 9) contents. Thermal transitions (mainly in a PEG phase) were investigated by differential scanning calorimetry. The dynamic behavior was investigated by thermally stimulated depolarization current and dielectric relaxation spectroscopy. The PEG crystallinity degree decreases in the nanocomposites, in particular at C PEG 40 wt %. A significant fraction of amorphous polymer is immobilized at a filler surface making no contribution to the glass transition, whereas the rest exhibits a lower glass transition temperature, when compared with bulk polymer, because of loosened molecular packing of the chains. Several relaxations arising from the polymer matrix, the filler, and their combination were identified and analyzed. The segmental a-relaxation of the PEG matrix was found to become faster in the nanocomposites.

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Section: Introductionmentioning

confidence: 99%

Thermal and dielectric studies of PEG/C/AST nanocomposites

Klonos

Kaprinis

Zarko

et al. 2012

J of Applied Polymer Sci

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“…Simultaneously, much attention has also been paid to PVA/silica hybrids. For example, Gunko et al [19] studied the interaction of PVA with fumed silica in the gas and aqueous media. It was found that strong hydrogen bonding exists between the PVA polymer molecules and silica particles.…”

Section: Introductionmentioning

confidence: 99%

Structure, Mechanical, and Swelling Behaviors of Poly(vinyl alcohol)/SiO2 Hybrid Membranes

Suo

Deng

2009

Journal of Reinforced Plastics and Composites

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Poly(vinyl alcohol) (PVA) has a wide application in industry and the biomedicine area, but its poor water resistance and insufficient mechanical strength have severely limited its application. To overcome these limitations, in this study, inorganic silica sol was used to modify organic PVA. The tensile results show that the tensile strength and Young’s modulus of these hybrid films were greatly improved compared to the neat PVA film. For the sample containing 20 wt% silica, compared to PVA matrix, considerable increases in tensile strength and Young’s modulus by factors of 1.9 and 3.2, respectively, were achieved. The solubility measurements showed that the hybrid has an enhanced water resistance, in other words, the solubility and degree of swelling decreased with the addition of silica. FTIR, DSC, XRD, and ESEM were used to investigate the chemical and crystal structure of the hybrids, morphology, and composition of the particles in the matrix, respectively. Strong interfacial bonding between the silica and the PVA matrix and homogenous distribution of the silica particles in PVA are supportive of markedly improved mechanical strength. These modified properties of PVA with the addition of silica broaden the applications of PVA, especially giving insight in to the applications of PVA in medical materials.

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“…This change, however, is in accordance with the requirements for the tape casting process 8 . The remarkable influence of the rheological behavior of the PVA solution on silica aqueous suspensions has already been reported 33 …”

Section: Resultsmentioning

confidence: 91%

Colloidal Processing of Glass–Ceramics for Laminated Object Manufacturing

Gomes

Rambo

Oliveira

et al. 2009

Journal of the American Ceramic Society

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Green tapes of Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 (LZSA) parent glass were produced by aqueous tape casting as the starting material for the laminated object manufacturing (LOM) process. The rheological behavior of the powder suspensions in aqueous media, as well as the mechanical properties of the cast tapes, was evaluated. According to n potential measurements, the LZSA glass powder particles showed acid surface characteristics and an IEP of around 4 when in aqueous media. The critical volume fraction of solids was about 72 wt% (27 vol%), which hindered the processability of more concentrated slurries. The glass particles also showed an anisometric profile, which contributed to an increase in the interactions between particles during flow. Therefore, the suspensions could not be processed at high solids loadings. Aqueous-based glass suspensions were also characterized by shear thickening after the addition of dispersants. Three slurry compositions were formulated, suitable green tapes were cast, and tapes were successfully laminated by LOM to a gear wheel geometry. A higher tensile strength of the green tapes corresponded to a higher tensile strength of the laminates. Thermal treatment was then applied to the laminates: pyrolysis at 5251C, sintering at 7001C for 1 h, and crystallization at 8501C for 30 min. A 20% volumetric shrinkage was observed, but no surface flaws or inhomogeneous areas were detected. The sintered part maintained the curved edges and internal profile after heat treatment.

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Relaxation phenomena in poly(vinyl alcohol)/fumed silica affected by interfacial water

Cited by 24 publications

References 56 publications

Thermal and dielectric studies of PEG/C/AST nanocomposites

Thermal and dielectric studies of PEG/C/AST nanocomposites

Structure, Mechanical, and Swelling Behaviors of Poly(vinyl alcohol)/SiO2 Hybrid Membranes

Colloidal Processing of Glass–Ceramics for Laminated Object Manufacturing

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