Synthesis of high molecular weight polymer nanoparticles by [Cp₂ZrCl₂] catalyzed emulsion polymerization

Abstract

An early transition metal metallocene compound, Cp2ZrCl2, with an anionic surfactant, sodium n‐dodecyl sulfate (SDS) as emulsifier and NaBPh4 as cocatalyst has been found to be an effective catalytic system for polymerization and copolymerization of monomers like styrene and methyl methacrylate in aqueous medium. The diameters of the latex particles were found to be in between 20 and 40 nm. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Aqueous emulsion homo- and copolymerization of 1,3-dienes and styrene in the presence of Cp2TiCl2

“…[28][29][30][31] Organo-titanium (III) species, which are readily obtained by the reduction of inexpensive Cp 2 TiCl 2 with Zn, have been reported to catalyze styrene, substituted styrene or conjugated diene living radical polymerization initiated by epoxides, peroxides or aldehydes. [28][29][30][31] In the literature, a few articles by Bhattacharjee et al [32][33][34][35][36] have described the use of Cp 2 MCl 2 (with Cp ¼ cyclopentadienyl and M ¼ Ti, Zr) as an active catalytic precursor for the aqueous emulsion homopolymerization of styrene and methylmethacrylate. This Cp 2 MCl 2 -catalyzed reaction produced stereoirregular polymers that had high molecular weights.…”

“…This Cp 2 MCl 2 -catalyzed reaction produced stereoirregular polymers that had high molecular weights. [32][33][34][35][36] Moreover, in these reports, it has been hypothesized that the active catalytic species could be a cation such as [Cp 2 MOH] þ , which is one of the species formed by the hydrolysis of Cp 2 MCl 2 , 37 stabilized by the large non-coordinating anion n-dodecylsulfate and utilized as an emulsifier. [32][33][34][35][36] Although the polymerization mechanism has not been definitively determined, the authors suggested that the polymerization reaction start by insertion of a monomer into the 'labile' metal-hydroxyl group bond, which excludes the possibility of free radical or spontaneous polymerization.…”

“…[32][33][34][35][36] Moreover, in these reports, it has been hypothesized that the active catalytic species could be a cation such as [Cp 2 MOH] þ , which is one of the species formed by the hydrolysis of Cp 2 MCl 2 , 37 stabilized by the large non-coordinating anion n-dodecylsulfate and utilized as an emulsifier. [32][33][34][35][36] Although the polymerization mechanism has not been definitively determined, the authors suggested that the polymerization reaction start by insertion of a monomer into the 'labile' metal-hydroxyl group bond, which excludes the possibility of free radical or spontaneous polymerization. [32][33][34][35][36] Herein, we present the first report on the aqueous emulsion homopolymerization of 1,3-butadiene and isoprene catalyzed by Cp 2 TiCl 2 with sodium dodecylsulfate as a co-catalyst and the copolymerization of both diene monomers with styrene.…”

“…[32][33][34][35][36] Although the polymerization mechanism has not been definitively determined, the authors suggested that the polymerization reaction start by insertion of a monomer into the 'labile' metal-hydroxyl group bond, which excludes the possibility of free radical or spontaneous polymerization. [32][33][34][35][36] Herein, we present the first report on the aqueous emulsion homopolymerization of 1,3-butadiene and isoprene catalyzed by Cp 2 TiCl 2 with sodium dodecylsulfate as a co-catalyst and the copolymerization of both diene monomers with styrene. The homoand copolymers were characterized using nuclear magnetic resonance spectroscopy (NMR) and thermal analysis, and their molecular weights and polydispersity index values were also determined using gel permeation chromatography.…”