Dynamics of adsorbed poly(methyl acrylate) and poly(methyl methacrylate) on silica

Blum, Frank D.; Lin, Wuu-Yung; Porter, Crystal

doi:10.1007/s00396-002-0795-8

Cited by 19 publications

(19 citation statements)

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“…Blum et al have studied how particle curvature, surface adsorption and composition influence the polymer free volume observed as changes in glass transition temperature and deuterium NMR relaxation [15,22,23]. Interfacial adsorption has also been shown to affect polymer chain density and mobility at the interface [22][23][24]. We suspected that the interface effects on free volume could influence the dielectric breakdown resistance and have previously seen that greater free volume for polymers of identical structure reduces electrical breakdown resistance.…”

Section: Resultsmentioning

confidence: 89%

“…Others have discussed surface modification and its relevance to dispersion quality and dielectric properties, in particular, breakdown strength [4,5,11,16]. Blum et al have studied how particle curvature, surface adsorption and composition influence the polymer free volume observed as changes in glass transition temperature and deuterium NMR relaxation [15,22,23]. Interfacial adsorption has also been shown to affect polymer chain density and mobility at the interface [22][23][24].…”

Section: Resultsmentioning

confidence: 99%

“…An increased free volume of the chains at the interface may be similar in effect to increased crystallinity, which increases the mean free path length of an accelerated electron and decreases breakdown strength [27], despite the fact that the polymer matrix is non-crystalline. A weakly adsorbed interface could also explain an increased free volume [15,22,23], which would also reduce electromechanical strength [28]. However, when amino groups were present on the surface, capable of covalently reacting with the epoxy polymer matrix, it could cross-link the polymer-particle interface to locally retain the bulk T g and free volume of the native epoxy polymer.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Improved Dielectric Breakdown Strength of Covalently-Bonded Interface Polymer–Particle Nanocomposites

Schuman

Siddabattuni

Cox

et al. 2010

Composite Interfaces

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Interfacial covalent bonding is an effective approach to increase the electrical resistance of a polymerparticle composite to charge flow and dielectric breakdown. A bifunctional tether reagent bonded to an inorganic oxide particle surface assists with particle dispersion within a thermosetting epoxy polymer matrix but then also reacts covalently with the polymer matrix. Bonding the particle surface to the polymer matrix resulted in a composite that maintained the pure polymer glass transition temperature, compared to modified or unmodified particle dispersions that lacked covalent bonding to the polymer matrix, which depressed the polymer glass transition to lower temperatures. The added interfacial control, directly bonding the particle to the polymer matrix, appears to prevent conductive percolation across particle surfaces that results in a reduced Maxwell-Wagner relaxation of the polymer-particle composite and a reduced sensitivity to a dielectric breakdown event. The inclusion of 5 vol% particles of higher permittivity produces a composite of enhanced dielectric constant and, with surface modification to permit surface cross-linking into the polymer, a polymer-particle composite with a Weibull E 0 dielectric breakdown strength of 25% greater than that of the pure polymer resulted. The estimated energy density for the cross-linked interface composite was improved 260% compared to the polymer alone, 560% better than a polymer-particle composite synthesized using bare particles, and 80% better than a polymer-particle composite utilizing bare particles with a dispersant.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Improved Dielectric Breakdown Strength of Covalently-Bonded Interface Polymer–Particle Nanocomposites

Schuman

Siddabattuni

Cox

et al. 2010

Composite Interfaces

View full text Add to dashboard Cite

show abstract

“…Above this domain, the saturated layer is composed of trains and loops protruding into the bulk, which are relatively more mobile. At the lowest adsorption amounts, one may envision the colloid surface to contain polymers with flatter conformations and, therefore, shorter, or fewer, loops as well as polymer-free areas [17]. This representation of the polymer interface accords with the finding that the polymer bulk concentration may control the amount and the conformation of the adsorbed macromolecules, and thus the aerosil stability when interparticle bridging is the destabilizing process.…”

Section: Influence Of the Polymer Dose On The Characteristics Of The mentioning

confidence: 60%

Anisotropic crystal growth in aerosil/polymethylmethacrylate systems dispersed in dimethacrylate monomers

Pefferkorn

Maaloum

Haïkel

et al. 2007

Journal of Colloid and Interface Science

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“…Other studies [37,38] [39] or may act to disrupt polymer chain crosslinking [40,41] which, in both cases, leads to a reduction in T g . Conversely, many other experimental [33,42] and molecular dynamics simulation [27] studies have indicated that strong filler/matrix interactions might reduce the local polymer chain mobility and thus yield a more rigid polymer with higher T g . In the current investigation, if any of the physically induced effects is dominant, then the variations in T g should be a function of the filler loading not the HP.…”

Section: Glass Transition Temperaturementioning

confidence: 94%

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

et al. 2017

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The addition of nanofillers can have a significant influence on the resin stoichiometry of thermosetting polymer systems. Based on differential scanning calorimetry (DSC) results, it is estimated that the inclusion of 2 and 5 wt% of silicon nitride nanofiller displaces the resin/hardener stoichiometry of an epoxy/amine network by 6.5 and 18%, respectively. Dielectric spectroscopy results confirm the above findings, in that the spectra of the nanocomposite samples were found to be equivalent to the spectra of unfilled samples when the above stoichiometric effect was taken into account. Therefore, this study provides clear evidence that the presence of a nanofiller can directly and significantly affect the curing process of an epoxy network. Consequently, this should always be considered when introducing nanofillers into thermosetting matrices. These results indicate the presence of covalent bonding between the nanoparticles and the surrounding polymer and, therefore, provide an opportunity to explore the influence of this bonding on the molecular dynamics of the polymer layer around the particles. However, the obtained DSC and dielectric spectroscopy results suggest that, in the system considered here, either the covalent bonding does not have an appreciable influence on the segmental dynamics of the polymer, as revealed by these techniques, or that the thickness of the affected layer is less than 1 nm and therefore too small to be distinguished from experimental uncertainties.

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Dynamics of adsorbed poly(methyl acrylate) and poly(methyl methacrylate) on silica

Cited by 19 publications

References 0 publications

Improved Dielectric Breakdown Strength of Covalently-Bonded Interface Polymer–Particle Nanocomposites

Improved Dielectric Breakdown Strength of Covalently-Bonded Interface Polymer–Particle Nanocomposites

Anisotropic crystal growth in aerosil/polymethylmethacrylate systems dispersed in dimethacrylate monomers

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

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