Polymerization in the presence of seeds. Part IV: Emulsion polymers containing inorganic filler particles

Hergeth, Wolf‐Dieter; Steinau, U.‐J.; Bittrich, H.‐J.; Simon, Géza; Schmutzler, K.

doi:10.1016/0032-3861(89)90114-6

Cited by 97 publications

(39 citation statements)

References 9 publications

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“…The first mechanism is caused by the reaction of the crosslink agent with the epoxy groups giving rise to the dominant !-relaxation, while the second one appears as a result of the filler's effect on the curing reaction. The formation of a few nanometres thick intermediate layer on the resin-filler interface, as it has already been reported in [4,5,11,22], probably occurs before the full cure of the composite, thereby inducing the growth of the secondary peak demonstrated in Figure 2. However, as the crosslink density increases in the post-cured composites, the interface region is significantly reduced and the sub-T g relaxations disappear due to the final incorporation of the loose chains into the main network.…”

Section: Sub-cured Dgeba/teta/cb Compositessupporting

confidence: 61%

“…Specifically, the effects of the nanofillers in polymer composites on the glass transition (T g ) and on the relaxation behaviour of the polymer matrix have been studied for different filler-resin composites. However, the remarks on T g variation are controversial as in some cases an increase in T g with filler content is reported in the literature [3][4][5], yet the opposite result is possible as well [6,7]. Additionally, the variation of T g as a function of filler content in epoxy nanocomposites shows an initial decrease up to a certain content value followed by an increase at higher filler loading [8,9].…”

Section: Introductionmentioning

confidence: 99%

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A detailed study of α-relaxation in epoxy/carbon nanoparticles composites using computational analysis

Stimoniaris¹,

Stergiou²,

Delides³

2012

Express Polym. Lett.

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Abstract. Nanocomposites were fabricated based on diglycidyl ether of bisphenol A (DGEBA), cured with triethylenetetramine (TETA) and filled with: a) high conductivity carbon black (CB) and b) amino-functionalized multiwalled carbon nanotubes (MWCNTs). The full dynamic mechanical analysis (DMA) spectra, obtained for the thermomechanical characterization of the partially cured DGEBA/TETA/CB and water saturated DGEBA/TETA/MWCNT composites, reveal a complex behaviour as the !-relaxation appears to consist of more than one individual peaks. By employing some basic calculations along with an optimization procedure, which utilizes the pseudo-Voigt profile function, the experimental data have been successfully analyzed. In fact, additional values of sub-glass transition temperature (T i ) corresponding to subrelaxation mechanisms were introduced besides the dominant process. Thus, the physical sense of multiple networks in the composites is investigated and the glass transition temperature T g is more precisely determined, as the DMA !-relaxation peaks can be reconstructed by the accumulation of individual peaks. Additionally, a novel term, the index of the network homogeneity (IH), is proposed to effectively characterize the degree of statistical perfection of the network.

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Section: Sub-cured Dgeba/teta/cb Compositessupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

A detailed study of α-relaxation in epoxy/carbon nanoparticles composites using computational analysis

Stimoniaris¹,

Stergiou²,

Delides³

2012

Express Polym. Lett.

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“…The conformation of these chains differs from that of the bulk polymer, producing a region with modified properties around each particle, typically referred to as the interphase. Changes in polymer mobility in this interfacial zone can lead to improvements of the mechanical properties (Forrest et al, 1996;Hergeth et al, 1989;Keddie et al, 1994). Since nanoscale fillers create a much greater interphase volume than micrometer-sized fillers at the same loading levels, nanoparticles will have a greater effect on the properties of the filled composite.…”

Section: Introductionmentioning

confidence: 98%

Microscopic measurement of the degree of mixing for nanoparticles in polymer nanocomposites by TEM images

Kim

Lee

Barry

et al. 2007

Microscopy Res & Technique

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For polymer nanocomposites, the small size of the fillers makes it difficult to analyze the degree of mixing quantitatively and often requires direct assessment via transmission electron microscopy (TEM). To date, qualitative comparisons and indirect measurements of the degree of mixing by measurement of certain properties are the most common methods. Better methods to quantitatively characterize the degree of mixing in nanocomposites would aid in studies investigating the effect of process conditions on the mixing behavior. Alumina/PET nanocomposites of identical composition, but with different degrees of mixing were prepared using a batch mixer. For evaluation of the degree of mixing with respect to both dispersion and distribution, three different techniques were applied and compared. TEM particle density was useful for dispersion, but did not adequately characterize distribution, while the Morisita's index gave poor results due to a wide range of effective particle sizes. Both methods ranked the samples differently compared to direct visual observation. In contrast, the skewness calculated by the quadrat method produced results consistent with visual rankings, and was found to be most effective in comparing and quantifying the degree of mixing. Although the quadrat method requires proper selection of quadrat size for a particular particle concentration, the skewness from the quadrat method was found to be most suitable as a standard index for the degree of mixing in nanocomposites. The usefulness of the quadrat method was verified using a second set of nanocomposites prepared by a twin screw extruder showing the potential for application of this technique for process development and quality control in commercial nanomanufacturing processes.

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“…Secondly, the use ganic materials obtained by emulsion polymerization, only few encapsulation studies have been performed on silicon of highly hydrophilic monomers (methyl methacrylate, vinyl acetate, ethyl acetate) are preferred to hydrophobic ones dioxide (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29), although synthetic silicas have gained importance in numerous fields of application. Since silica is (styrene).…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of Inorganic Particles by Dispersion Polymerization in Polar Media

Bourgeat‐Lami

Láng

1998

Journal of Colloid and Interface Science

426

275

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Polymerization in the presence of seeds. Part IV: Emulsion polymers containing inorganic filler particles

Cited by 97 publications

References 9 publications

A detailed study of α-relaxation in epoxy/carbon nanoparticles composites using computational analysis

A detailed study of α-relaxation in epoxy/carbon nanoparticles composites using computational analysis

Microscopic measurement of the degree of mixing for nanoparticles in polymer nanocomposites by TEM images

Encapsulation of Inorganic Particles by Dispersion Polymerization in Polar Media

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