Fluorous miniemulsions: A powerful tool to control morphology in metallocene‐catalyzed propene polymerization

Abstract

The nonaqueous miniemulsion polymerization of liquid propene using highly water sensitive metallocene catalysts is presented. In the emulsion perfluoromethylcyclohexane is applied as continuous phase in which the monomer is polymerized to high molecular weights. The droplets are stabilized by specially designed of hydrocarbon/perfluorinated block copolymers. This technique offers the possibility to generate polyolefin nanoparticles with a narrow size distribution and diameters below 100 nm. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Poly(isobutylene) Nanoparticles via Cationic Polymerization in Nonaqueous Emulsions

“…A clear shift in elution volume toward higher molecular masses was observed, and the polydispersity index (PDI) remained nearly identical with a value of 1.3. However, as previously described, poly(IB‐ b ‐PFS) does not stabilize the oil‐in‐perfluoroalkane emulsion …”

“…The δ t value for perfluorohexane (PFH) is 12 MPa 0.5 , and mixtures of n ‐hexane and n ‐perfluorohexane range between 15 and 20 MPa 0.5 . For stabilization of the PFH phase, a poly(pentafluorostyrene) (poly(PFS)) block was selected . Based on the δ t value for PIB ( δ t,PIB = 15 MPa 0.5 vs poly(styrene) (PS) δ t,PS = 22 MPa 0.5 ), a corresponding PIB block copolymer was chosen to stabilize the oil‐phase in the emulsion.…”

“…Nonaqueous, fluorous (oil‐in‐perfluoroalkane) emulsions have the potential to overcome these limitations in the polymerization of IB. In our previous work on metallocene‐catalyzed polymerization of propylene, the use of toluene‐in‐perfluoroalkane emulsions successfully avoided the deactivation of the catalyst . Perfluoroalkanes have the benefit of extremely low melting points and therefore, can be successfully utilized as the continuous phase without the need of additives.…”

Nanoparticles by ROMP in Nonaqueous Emulsions

“…[11,12] For even more sensitive catalysts such as metallocenes we developed a second emulsion system which is based on a perfluorinated solvent and a hydrocarbon. [13] However, catalytic polymerizations have not yet been performed in more polar nonaqueous systems such as N,N-dimethylformamide (DMF)/n-hexane. Therefore, Grubbs-type catalysts were used to perform ring opening metathesis polymerization (ROMP), as it is a very efficient way to yield high molecular weight polymers using a catalyst like benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro (tricyclohexylphosphine)ruthenium (secondgeneration Grubbs catalyst).…”

Nonaqueous and Aqueous Emulsion ROMP Reactions Induced by Environment-Friendly Latent Ruthenium Indenylidene Catalyst Bearing Morpholine Substituted Bidentate (N, O) Schiff Bases

“…Core–shell polymeric materials were also prepared by the same group using the same strategy . Perfluorinated solvent/hydrocarbons were used by the same research group in metallocene catalyzed propene polymerization . In 2010, Wagener and co‐workers have employed ROMP reactions to nonaqueous emulsion system using binary solvent system ( n ‐hexane/DMF) in the presence of Grubbs second generation catalyst …”