Polymerization of w/o Microemulsions for the Preparation of Transparent SiO₂/PMMA Nanocomposites

Abstract

Reverse w/o microemulsions composed of methyl methacrylate (MMA) forming the oil phase, nonionic surfactants, and water are used for the synthesis of transparent SiO2/PMMA nanocomposites. An inorganic precursor, tetraethoxysilane (Si(OEt)(4), TEOS), is hydrolyzed in the reverse micelles containing aqueous ammonia. During the hydrolysis of TEOS, polymerization of the continuous MMA phase is initiated using AIBN (azobisisobutyronitrile), and after thermal polymerization at 333 K for 12 h, solid blocks of PMMA are obtained in which nanometer-sized silica particles are trapped in the solid polymer matrix. According to small-angle X-ray and dynamic light scattering experiments, the water droplets in MMA microemulsions are 12 nm (R(W) = 13) in diameter, whereas after polymerization of the microemulsion, the SiO2 particles in the transparent SiO2/PMMA composites are 26 nm in diameter. Transmission electron micrographs demonstrate a low degree of agglomeration in the composites. In comparison with materials generated from micelle-free solutions, the particle size distribution is narrow. The reverse micelle-mediated approach produces composites of high transparency comparable with that of pure PMMA.

Nano‐Level Mixing of ZnO into Poly(methyl methacrylate)

“…[3] It is believed that polymers as hosts do not provide a sufficiently fluid environment to allow individual particles to meet with each other by diffusion; thereby, the aggregation of the particles may be prevented for reasons of kinetics. [4][5][6] However, the drawback is that the polymer may stay contaminated by unreacted educts or by-products of the precipitation reaction. In addition, it is difficult to control the particle size distribution of fillers in a polymer matrix.…”

In situ preparation and luminescent properties of LaPO4:Ce3+, Tb3+ nanoparticles and transparent LaPO4:Ce3+, Tb3+/PMMA nanocomposite

“…By now, several methods for preparing polymer nanocomposites such as sol-gel reactions [1][2][3][4][5], intercalative polymerization [6][7][8][9], melt-processing [10][11][12], and in situ polymerization [13][14][15][16] have been applied depending on the nature of nanoparticles and the synthesis and processing of polymeric matrices. Polymerization of inverse microemulsions is an important and more specialized method for the preparation of nanocomposites [17,18]. Inverse (waterin-oil) microemulsions are isotropic, transparent, thermodynamically stable media that consist of small water droplets surrounded by a surfactant monolayer and dispersed in an oil-rich continuous phase.…”

Surface functionalization of ZrO2 nanocrystallites for the integration into acrylate nanocomposite films

“…with the particles, the covalent attachment of an inert organic layer on the surface of the particle core, serving as a compatibilizer at the particle/polymer interface, the encapsulation of the particles by special polymerization techniques such as emulsion polymerization [18,19], the attachment of functional groups which allow for a covalent link with the polymer, or the attachment of initiation groups for grafting of polymer chains from the particle surface [20]. Another approach to produce metal oxide materials compatible with non-polar media is described by Terry et al…”