Polymer/Laponite

Fig. 31 Procedure used for the synthesis of polymer/Laponite composite particles through emulsion polymerization...

L, and Bourgeat-Lami, E. (2006) Polymer/laponite composite colloids through emulsion polymerization influence of the clay modification level on particle morphology. Macromolecules, 39, 9177-9184. 

Modeling and Online Monitoring by Calorimetry of the Preparation of Polymer-Laponite Nanocomposite Particles... 

V. Mellon Synthesis and characterization of waterborne polymer-Laponite nanocomposite latexes through miniemulsion polymerization, PhD thesis, Universite Claude Bernard Lyon 1, 2009. 

Lactate dehydrogenase, alcohol dehydrogenase Laponite gel-methylene blue polymer Biosensor [47]... 

Laponite, a synthetic hectorite clay, when suspended in water, forms disclike particles with a thickness of 1 nm, a diameter of about 25 nm, and a negative surface charge density stabilizing dispersions in water. Formation of a cross-linked polymer network using a small amount of Laponite indicates that these nanoparticles act as a multifunctional cross-linker with a large effective functionality (Okay and Oppermann 2007). 

Bon, Keddy, and coworkers [109] demonstrated that soft armored polymer latex made via Pickering miniemulsion polymerization [i.e., poly(lauryl acrylate) armored with Laponite clay discs] could be used as a nanocomposite additive in standard poly(butyl acrylate-co-acrylic acid) waterborne pressure-sensitive adhesives (PSAs), leading to marked mechanical property enhancements (see Fig. 13). 

In the second part of this article, polymer latexes surrounded by anisotropic Laponite platelets have been successfully obtained by the two routes. It was demonstrated that the clay particles play the role of a pickering stabilizer and are capable to stabilize the composite particles whose diameter depends on the amount of Laponite initially introduced into the reactor. The higher the clay concentration, the larger the composite particle number and, therefore, the higher the polymerization rate as predicted from the emulsion polymerization theory. 

The structure and dynamics of surfactant and polymer chains in intercalated poly(8-caprolactone)/ clay nanocomposites are characterized by P magic-angle spinning (MAS) and C cross-polarization MAS NMR techniques. To obtain hybrid materials with the low polymer content required for this study, in situ intercalative polymerization was performed by adapting a published procedure. After nanocomposite formation, the chain motion of the surfactant is enhanced in the saponite-based materials but reduced in the laponite ones. Compared to the initial clay, the trani -conformer population of the surfactant hydrocarbon chains in the nanocomposite decreases for the saponite systems. Mobility of the polymer chain is higher in the nanocomposites than in the bulk phase. The charge of the modified saponite does not significantly inflnence chain mobility in the nanocomposites. 

VanderHart et al. (2001a-c) studied different clay nanocomposites measuring clay exfoliation by relaxation times of hydrogen that sees iron in the montmorillonite clay. They used Fe atoms in montmorillonite clay to determine clay dispersion in Nylon-6 matrix, and degraded alkyl ammoniums (from thermal processing above 200 C) were observed by NMR technique. Hou et al. (2002,2003) studied clay intercalation of poly(styrene-ethylene oxide)-b/ocfe-copolymers using multinuclear solid-state NMR. Hrobarikova et al. (2004) prepared polycaprolactone with laponite or saponite nanocomposites by in sitn polymerization and characterized by CAP NMR to understand how surfactants at clay surface interacted with polymer matrix. Hrobarikova et al. (2004) used solid-state NMR to study intercalated species in poly(e-caprolactone)/clay nanocomposites. 

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