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Summary: The chemical metallization of aqueous bentonite dispersions afforded stable aqueous hybrid nanoparticle dispersions containing simultaneously dispersed sodium bentonite nanoplatelets together with bentonite supported silver, palladium, or copper nanoparticles with average metal nanoparticle diameters varying between 14 and 40 nm. Such aqueous bentonite/metal hybrid nanoparticle dispersions were blended with cationic PMMA latex to produce PMMA hybrid nanocomposites containing exfoliated polymer‐grafted organoclay together with bentonite supported metal nanoparticles. This dispersion blend formation was investigated with respect to the role of nanostructure formation and mechanical properties. Palladium/bentonite hybrid dispersions were used as catalysts for hydrogenation reactions and the electroless plating of copper. In contrast to the conventional organoclay nanocomposites, the PMMA hybrid nanocomposites, containing simultaneously dispersed organoclay nanoplatelets together with organoclay supported silver nanoparticles, exhibited high antimicrobial activity against the ubiquitous bacterium Staphylococcus aureus, even at low silver content.Preparation of a polymer hybrid nanocomposite.magnified imagePreparation of a polymer hybrid nanocomposite.

PMMA nanocomposites were prepared by means of self-assembly of polyhedral oligomeric silsesquioxanes (POSS) such as [Si8O12(OSiMe2H)(8)] (POSS1) and [Si7O9(cyclohexyl)(7)(OSiMe2H)(3)] (POSS2) during the free radical methyl methacrylate (MMA) bulk polymerization. The POSS phases separation and self-assembly afforded in situ nanocubes with average diameters ranging from 25 nm to 500 nm. The influence of 5.3 wt.% POSS on the thermal, mechanical and morphological PMMA nanocomposite properties was investigated. POSS mediated nanocube formation was accompanied by improvements of PMMA glass temperature and toughness. Depth profiling by means of ion beam Rutherford backscattering (RBS) analysis indicated the accumulation of POSS1 at the PMMA surface

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.

GMA) with the new macromonomers, initiator and glass filler. The composites showed compressive strengths up to 244 MPa, flexural strengths from 22 to 42 MPa and Young's moduli between 870 and 3 070 MPa. The composite materials exhibited low volume shrinkage of about 2 vol.-% in comparison to over 3 vol.-% shrinkage of commercially available composites.