“…Thus, the pH of the emulsion with C18DMB is influenced by the charge balance between the surfactant and the clay. There is definitely some penetration of the surfactant inside theclay layers, as observed in the functionalized clay reported in a previous paper . But some C18DMB is also present at the monomer−water interface, stabilizing the emulsion and avoiding coagulation.…”
Section: Resultssupporting
confidence: 62%
“…XRD of the dried polymer pellets as shown in Figure indicates a peak around 5°. This peak corresponds to a d spacing of 1.82 nm and is similar to the 5° peak of MMT ion-exchanged with BAC, indicating a poorly intercalated polymer composite. 1 XRD patterns of dried emulsion nanocomposite samples with BAC surfactant and C18DMB and, also, pattern of unmodified MMT at the bottom.…”
Section: Resultsmentioning
confidence: 63%
“…The TEM micrograph in Figure indicates that the final PMMA−clay nanocomposite was partially exfoliated. The morphology resembles that presented in refs and . For comparison, a PMMA−clay nanocomposite was prepared via in situ polymerization with same clay concentration of 10 wt %.…”
Section: Resultsmentioning
confidence: 70%
“…Previously, the PMMA nanocomposite was synthesized via in situ polymerization . In this paper, we describe the synthesis of the PMMA−clay nanocomposite with 10 wt % clay via emulsion polymerization at 60 °C with a focus on how the zwitterionic surfactant, octadecyl dimethyl betaine (C18DMB), affects the final product.…”
The synthesis of nanocomposites via emulsion polymerization was investigated using methyl methacrylate
(MMA) monomer, 10 wt % montmorillonite (MMT) clay, and a zwitterionic surfactant octadecyl dimethyl
betaine (C18DMB). The particle size of the diluted polymer emulsion was about 550 nm, as determined
by light scattering, while the sample without clay had a diameter of about 350 nm. The increase in the
droplet size suggests that clay was present in the emulsion droplets. X-ray diffraction indicated no peak
in the nanocomposites. Transmission electron microscopy showed that emulsion polymerization of MMA
in the presence of C18DMB and MMT formed partially exfoliated nanocomposites. Differential scanning
calorimetry showed an increase of 18 °C in the glass transition temperature (T
g) of the nanocomposites.
A dynamic mechanical thermal analyzer also verified a similar T
g increase, 16 °C, for the partially exfoliated
nanocomposites over poly(methyl methacrylate) (PMMA). Thermogravimetric analysis indicated a 37 °C
increase in the decomposition temperature for a 20 wt % loss. A PMMA nanocomposite with 10 wt %
C18DMB−MMT was also synthesized via in situ polymerization. This nanocomposite was intercalated
and had a T
g 10° lower than the emulsion nanocomposite. The storage modulus of the partially exfoliated
emulsion nanocomposite was superior to the intercalated structure at higher temperatures and to the pure
polymer. The rubbery plateau modulus was over 30 times higher for the emulsion product versus pure
PMMA. The emulsion technique produced nanocomposites of the highest molecular weight with a bimodal
distribution. This reinstates that exfoliated structures have enhanced thermal and mechanical properties
over intercalated hybrids.
“…Thus, the pH of the emulsion with C18DMB is influenced by the charge balance between the surfactant and the clay. There is definitely some penetration of the surfactant inside theclay layers, as observed in the functionalized clay reported in a previous paper . But some C18DMB is also present at the monomer−water interface, stabilizing the emulsion and avoiding coagulation.…”
Section: Resultssupporting
confidence: 62%
“…XRD of the dried polymer pellets as shown in Figure indicates a peak around 5°. This peak corresponds to a d spacing of 1.82 nm and is similar to the 5° peak of MMT ion-exchanged with BAC, indicating a poorly intercalated polymer composite. 1 XRD patterns of dried emulsion nanocomposite samples with BAC surfactant and C18DMB and, also, pattern of unmodified MMT at the bottom.…”
Section: Resultsmentioning
confidence: 63%
“…The TEM micrograph in Figure indicates that the final PMMA−clay nanocomposite was partially exfoliated. The morphology resembles that presented in refs and . For comparison, a PMMA−clay nanocomposite was prepared via in situ polymerization with same clay concentration of 10 wt %.…”
Section: Resultsmentioning
confidence: 70%
“…Previously, the PMMA nanocomposite was synthesized via in situ polymerization . In this paper, we describe the synthesis of the PMMA−clay nanocomposite with 10 wt % clay via emulsion polymerization at 60 °C with a focus on how the zwitterionic surfactant, octadecyl dimethyl betaine (C18DMB), affects the final product.…”
The synthesis of nanocomposites via emulsion polymerization was investigated using methyl methacrylate
(MMA) monomer, 10 wt % montmorillonite (MMT) clay, and a zwitterionic surfactant octadecyl dimethyl
betaine (C18DMB). The particle size of the diluted polymer emulsion was about 550 nm, as determined
by light scattering, while the sample without clay had a diameter of about 350 nm. The increase in the
droplet size suggests that clay was present in the emulsion droplets. X-ray diffraction indicated no peak
in the nanocomposites. Transmission electron microscopy showed that emulsion polymerization of MMA
in the presence of C18DMB and MMT formed partially exfoliated nanocomposites. Differential scanning
calorimetry showed an increase of 18 °C in the glass transition temperature (T
g) of the nanocomposites.
A dynamic mechanical thermal analyzer also verified a similar T
g increase, 16 °C, for the partially exfoliated
nanocomposites over poly(methyl methacrylate) (PMMA). Thermogravimetric analysis indicated a 37 °C
increase in the decomposition temperature for a 20 wt % loss. A PMMA nanocomposite with 10 wt %
C18DMB−MMT was also synthesized via in situ polymerization. This nanocomposite was intercalated
and had a T
g 10° lower than the emulsion nanocomposite. The storage modulus of the partially exfoliated
emulsion nanocomposite was superior to the intercalated structure at higher temperatures and to the pure
polymer. The rubbery plateau modulus was over 30 times higher for the emulsion product versus pure
PMMA. The emulsion technique produced nanocomposites of the highest molecular weight with a bimodal
distribution. This reinstates that exfoliated structures have enhanced thermal and mechanical properties
over intercalated hybrids.
“…The strong interactions taking place during melt intercalation among PMMA, surfactant and clay, can also be expected to occur in other techniques of nanocomposite synthesis. This could explain the formation of partially exfoliated PMMA-clay nanocomposite synthesized in our laboratory using in situ and emulsion polymerization [3,4]. Poly(ethylene oxide) is also examined in the model and due to its very strong polarity exhibits stronger interaction with the surfactant and the clay surface than the other polymers investigated.…”
Ein Krake zur Analyse: CaCO3‐Poly(methylmethacrylat)(PMMA)‐Nanopartikel mit zerstörbarem CaCO3‐Kern wurden zur Anreicherung von gering konzentrierten Peptiden und Proteinen verwendet. Die linearen, am CaCO3‐Kern verankerten PMMA‐Ketten greifen die Analyte wie die Arme eines Kraken. Nach Entfernung des CaCO3‐Kerns werden die adsorbierten Peptide oder Proteine durch MALDI‐TOF‐Massenspektrometrie analysiert (siehe Schema).
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