Synthesis of Very Small Polymer Particles by Catalytic Polymerization in Aqueous Systems

Abstract

Summary:The preparation of aqueous dispersions of very small particles (size < 30 nm) of various polymers (polyethylenes, stereoregular 1,2-polybutadiene, and polyalkenamers) by catalytic polymerization with a water-soluble catalyst, or with microemulsions of lipophilic catalysts is reviewed.

Metallocene‐Catalyzed Polymerization in Nonaqueous Fluorous Emulsion

“…[10] This results in particles without supported process, and their size might be decreased to the nanometer region. [11,12] A major drawback is that only a few catalyst systems tolerate water, the majority being extremely water sensitive. Metallocenes, being able to produce high molecular weight polyolefins, are easily decomposed.…”

“…As a result, polyolefins produced inside an emulsion have had, thus far, relatively low molecular weights in comparison to metallocene or postmetallocene-catalyzed processes. [11,12] Herein, the utilization of a nonaqueous, oil-in-oil emulsion is proposed as one possibility to overcome these challenges. It has already been shown that water-free emulsions of acetonitrile/hydrocarbon offer the opportunity to use water-sensitive catalytic systems to form polyacetylene.…”

Simultaneous ROMP and ATRP in Aqueous Dispersed Media: A Straightforward Strategy to Prepare Polymer Composite Particles with Original Morphologies

“…So as to get rid of this issue, we later proposed to use directly the commercial hydrophobic shape of GC1 using a new alternative [19] inspired by the work of Mecking and coworkers on microemulsion ROMP. [20,21] The approach is based on the use of two aqueous microemulsions: the first one has a dispersed phase composed of the monomers (NB, MMA and Ethyl 2-chloropropionate or I1) whereas the droplets of the second one contain GC1 solubilised in toluene. Once they have been mixed together, thermodynamically driven exchanges between the droplets of both microemulsions enable GC1 to meet the other reagents and thus to trigger off the ROMP of NB and the ATRP of MMA.…”

Emulsion processing of polymer-derived porous Si/C/(O) ceramic bodies

“…24 The stabilisation of oil/water interfaces with surfactants has also potential for structuring of polymer-derived ceramics. The emulsion droplets can be used as templates/microreactors for polymerisation reactions 25,26 and colloid synthesis, 27 which govern the final particle size. Depending on the particle size (crude) turbid unstable emulsions (few microns) and thermodynamically stable translucent microemulsions (10-40 nm) are discerned.…”