Synthesis and Structure Characterization of Acrylic-Clay Nanocomposite Pressure-sensitive Adhesives

3 Synthesis and Structure Characterization of Acrylic-Clay Nanocomposite Pressure-sensitive Adhesives 

Waterborne acrylic-clay nanocomposite PSAs have been synthesized by suspension polymerization, emulsion polymerization and Pickering miniemulsion polymerization of a soft acrylate monomer in the presence of clay, which was followed by blending the polymer-clay nanocomposite particles with a standard acrylate latex for application as a waterborne PSA.  

Acrylic-Clay Nanocomposites by Suspension and Emulsion Polymerization 115 

Rana et al prepared P(2-EHA)-silicate nanocomposites by batch emulsion polymerization of 2-EHA in the presence of sorbitol, using potassium persulfate as initiator. The nanocomposites so prepared were shown to be intercalated by XRD, TEM and IR spectroscopy. However, according to the authors, the nanocomposite failed to satisfy the desired application in transdermal drug delivery. Consequently, they improved their product by preparing a P(2-EHA-cu-AA)-silieate nanocomposite. AA was chosen for its polarity and known bioadhesive properties and 2-EHA for its hydrophobicity and softness. Copolymers with different molar ratios of the monomers were prepared. Sorbitol was used as emulsifier and benzoyl peroxide as initiator therefore, the synthesis process may be classified as suspension copolymerization. The drug cloxacillin sodium was added to the reaction mixture after 2 h of polymerization and 1 h before the reaction was terminated. The nanocomposites so prepared were shown to be intercalated by XRD and TEM. NMR and IR spectroscopy confirmed the copolymer formation and the absence of monomer impurities in the product. 

Wang et al. succeeded in preparing waterborne PSAs with nanostructured features that ean build in an energy dissipation mechanism without stiffening the structure too much. In their study, soft-hard polymer particles having Laponite clay armor were synthesized by the Pickering miniemulsion polymerization of -lauryl acrylate (LA). The resulting poly(lauryl acrylate) (PLA)-Laponite hybrid particles were then blended at various low concentrations with 

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