Synthesis of poly(methylmethacrylate)/montmorillonite nanocomposites via in situ intercalative suspension and emulsion polymerization

Essawy, Hisham; Badran, A. S.; Youssef, Ahmed M.; El-Hakim, Abu El-Fetoh Abd

doi:10.1007/s00289-004-0312-y

Cited by 46 publications

(12 citation statements)

References 13 publications

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“…It was found that the tendency for exfoliation is more pronounced in the case of CTAB for the same concentration of the initiator; CTAB is thought to be more compatible with styrene than CPC and, hence, provides a rapid and higher swelling capacity of the CTAB‐MMT in styrene, consequently making the reaction more favorable and leading to exfoliated nanocomposites. On the other hand, we found the opposite in our previous study when styrene was exchanged with methyl methacrylate and polymerized under the same conditions;12 thus, the compatibility of the organoclay with the monomer plays an influential role in determining the microstructure of the resulting nanocomposite. It is also observed that increasing the initiator concentration from 2.1 × 10 −4 to 2.1 × 10 −3 mol/l was associated with more expansion in the d 001 spacing from 35.3 to 36.12 Å in the case of treatment with CPC.…”

Section: Resultsmentioning

confidence: 99%

Polystyrene/Montmorillonite Nanocomposites Prepared by In Situ Intercalative Polymerization: Influence of the Surfactant Type

Essawy¹,

Badran²,

Youssef³

et al. 2004

Macro Chemistry & Physics

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Summary: Na‐montmorillonite (MMT) with a cation exchange capacity (CEC) of 90 meq/100 g was converted to MMT‐CTAB and MMT‐CPC by the intercalation of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC), respectively. The intercalation of CPC onto the basal space of the montmorillonite expanded the basal space from 12.19 to 21.47 Å, whereas in the case of CTAB, the spacing was only expanded to 19.35 Å. The MMT‐CPC and MMT‐CTAB forms were subsequently used as hosts for the preparation of polystyrene nanocomposites via intercalative free‐radical polymerization of styrene. Different structures were obtained by varying the preparation conditions; the exfoliated and intercalated nanocomposites were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and differential scanning calorimeter (DSC). The produced nanocomposites exhibited improved thermal stability in comparison with that of pure polystyrene above 400 °C especially in the case of the nanocomposites based on the MMT‐CPC, in which intercalation exists. A glass transition temperature (Tg) could not be detected for the prepared nanocomposites using DSC; this was assumed to result from the restricted molecular motion of the polymer chains.XRD pattern of PS nanocomposites prepared by intercalative polymerization.magnified imageXRD pattern of PS nanocomposites prepared by intercalative polymerization.

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Section: Resultsmentioning

confidence: 99%

Polystyrene/Montmorillonite Nanocomposites Prepared by In Situ Intercalative Polymerization: Influence of the Surfactant Type

Essawy¹,

Badran²,

Youssef³

et al. 2004

Macro Chemistry & Physics

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“…Many attempts have been reported to incorporate organoclay in poly(methyl methacrylate) (PMMA), polystyrene (PS), or polyurethanes (PU), aiming at obtaining improved properties resulting from intercalation and exfoliation of organoclays. Organoclay dispersions in monomer were polymerized in bulk,9–15 solution,16–21 and also in aqueous emulsions 22–33. Alternatively, extrusion of polymer melts was employed successfully to prepare thermoplastic organoclay nanocomposites 34–36.…”

Section: Introductionmentioning

confidence: 99%

A Versatile Solvent‐Free “One‐Pot” Route to Polymer Nanocomposites and the in situ Formation of Calcium Phosphate/Layered Silicate Hybrid Nanoparticles

Weickmann

Gurr

Meincke

et al. 2010

Adv Funct Materials

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Poly(methyl methacrylate) (PMMA), polystyrene (PS), and polyurethane (PU) nanocomposites containing well‐dispersed calcium phosphate/layered silicate hybrid nanoparticles were prepared in a versatile solvent‐free “one‐pot” process without requiring separate steps, such as organophilic modification, purification, drying, dispersing, and compounding, typical for many conventional organoclay nanocomposites. In this “one‐pot” process, alkyl ammonium phosphates were added as swelling agents to a suspension of calcium/layered silicate in styrene, methyl methacrylate, or polyols prior to polymerization. Alkyl ammonium phosphates were prepared in situ by reacting phosphoric acid with an equivalent amount of alkyl amines such as stearyl amine (SA) or the corresponding ester‐ and methacrylate‐functionalized tertiary alkyl amines, obtained via Michael Addition of SA with methyl acrylate or ethylene 2‐methacryloxyethyl acrylate. Upon contact with the calcium bentonite suspension, the cation exchange of Ca2+ in the silicate interlayers for alkyl ammonium cations rendered the bentonite organophilic and enabled effective swelling in the monomer accompanied by intercalation and in situ precipitation of calcium phosphates. According to energy dispersive X‐ray analysis, the calcium phosphate precipitated exclusively onto the surfaces of the bentonite nanoplatelets, thus forming easy‐to‐disperse calcium phosphate/layered silicate hybrid nanoparticles. Incorporation of 5–15 wt% of such hybrid nanoparticles into PMMA, PS, and PU afforded improved stiffness/toughness balances of the polymer nanocomposites. Functionalized alkyl ammonium phosphate addition enabled polymer attachment to the nanoparticle surfaces. Transmission electron microscopy (TEM) analyses of PU and PU‐foam nanocomposites, prepared by dispersing hybrid nanoparticles in the polyols prior to isocyanate cure, revealed the formation of fully exfoliated hybrid nanoparticles.

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“…Polymer/clay nanocomposites (PCNs) have become an area of sustained interest with several recent reviews on PCNs in the literature 1–3. Furthermore, it has been reported that increases in the thermal stability,4–7 flame retardency,8–11 tensile strength,12–14 and glass‐transition temperature15–18 have been achieved in PCNs compared to the values for pure polymer matrices. One of the advantages of clay is that smaller percentages of clay (<10%), compared to conventional fillers, are required to provide improved material properties.…”

Section: Introductionmentioning

confidence: 99%

Suspension polymerization of poly(methyl methacrylate)/clay nanocomposites

Clarke

Robinson

Elder

et al. 2009

J of Applied Polymer Sci

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Polymer/clay nanocomposites (PCNs) of poly(methyl methacrylate) and an organically modified clay, Cloisite 15a, were synthesized in situ with a suspension polymerization technique. The amount of clay present in the PCNs was varied to provide a better understanding of the effect of the clay on the properties of the polymer matrix. However, unexpectedly, we found that the concentration of clay had a dramatic impact on the molecular weight of the polymer matrix, and a relationship between the clay concentration and polymer molecular weight was determined. The PCNs were characterized with size exclusion chromatography (SEC), X-ray diffraction, transmission electron microscopy, and oscillatory shear rheology.From oscillatory shear rheology, the full master curves for the PCNs were obtained by application of the time-temperature superposition principle. To enable the effect of the clay on the rheology to be quantified, the experimental data was compared to the time-dependent diffusion model of des Cloizeaux for polydisperse polymer melts, which enabled the polydispersity to be incorporated through the use of the molecular weight distribution obtained via SEC.

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Synthesis of poly(methylmethacrylate)/montmorillonite nanocomposites via in situ intercalative suspension and emulsion polymerization

Cited by 46 publications

References 13 publications

Polystyrene/Montmorillonite Nanocomposites Prepared by In Situ Intercalative Polymerization: Influence of the Surfactant Type

Polystyrene/Montmorillonite Nanocomposites Prepared by In Situ Intercalative Polymerization: Influence of the Surfactant Type

A Versatile Solvent‐Free “One‐Pot” Route to Polymer Nanocomposites and the in situ Formation of Calcium Phosphate/Layered Silicate Hybrid Nanoparticles

Suspension polymerization of poly(methyl methacrylate)/clay nanocomposites

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