The preparation of monodisperse polyacrylonitrile particles in the presence of AB block co-polymers of poly-2-vinylpyridine/poly tertbutylstyrene

Dispersion polymerization in non-polar solvent: Evolution toward emerging applications

“…With the PDMS-b-PS-b-PDMS stabilizer, increasing stabilizer coverage encouraged more exposed tails, leading to greater particle stability. However, for sufficiently large stabilizers, the effect of molecular weight became insignificant as the solubilising blocks appeared to create enough stabilizing effect [16,95]. Meanwhile, varying the initiator concentration did not seem to affect the particle size [95].…”

“…A minimum of 60 mol% solubilising PODA block was required to produce stable particle dispersions. Generally, it was observed that with increasing stabilizer concentration, smaller PAN particles were obtained [16,95,96]. With the PDMS-b-PS-b-PDMS stabilizer, increasing stabilizer coverage encouraged more exposed tails, leading to greater particle stability.…”

Preparation of Linear and Crosslinked Polymer Microspheres by Dispersion Polymerization

“…Dispersion polymerization has been carried out with a variety of monomers to form homopolymers as well as copolymers (14,21,26,28,32,33,(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48). However, the most extensively researched monomers are styrene and MMA.…”

Uniform polymer beads of micrometer size

“…The solvency (polarity) of the reaction medium and consequently the overall bead size is also affected by monomer concentration, and by the co-monomer ratio. Further, dispersion polymerizations of vinyl acetate in isooctane [70], acrylonitrile in cyclohexane [71], N-vinylformamide (with or without crosslinking agents such as N,N-methylenebisacrylamide or ethylene dimethacrylate) in methanol [72] and 2-hydroxyethyl methacrylate in toluene/isobutyl alcohol system [73] affording monosized beads have been described. This is, however, usually accompanied by the broadening of bead size distribution [60, 611. If hydrocarbon media (e.g., heptane, Isopar G and toluene, dodecane) are used in the free-radical dispersion polymerization of styrene or methyl methacrylate, the bead size is typically in the submicrometer range and suitable for use in paints [15].…”

“…Examples of stabilizers for non-polar dispersion media (typically, petroleum hydrocarbons) include poly(laury1 methacrylate), poly(buty1 methacrylate), poly(viny1 stearate), poly(l2-hydroxystearic acid), poly(2-ethylhexyl methacrylate), poly(dimethylsiloxane), poly(dimethylsi1oxane-block-styrene) [76], poly(styrene-b/ock-4-(trimethylsi-1yl)styrene) 1621, poly(styrene-block-butadiene), poly-(styrene-block-tert-butylstyrene) [79], poly(2-vinylpyridineblock-tert-butylstyrene) [71], and poly(isobuty1ene-coisoprene). Highly polar polymers such as poly(N-vinylpyrrolidone), hydroxypropyl cellulose, poly(acry1ic acid), poly-(vinyl butyral), poly(viny1 methyl ether), poly(Wviny1pyrrolidone-co-vinyl acetate), poly(acry1amide) [38], poly(2ethyl-2-oxazoline) [78], and poly(ethy1enimine) have been used as steric stabilizers in the dispersion polymerization of styrene in polar media.…”