Dicyanovinyl acrylates

Fig. 6.7. Viscosity sensitive fluorophores molecular rotors. DCVJ = 9-(dicyanovinyl)-julolidine, CCVJ = 9-(carboxy-2-cyano)vinyl julolidine, CMAM = 2-cyano-3-(p-dimethyl-aminophenyl)acrylic acid, methyl ester.

Dispersion polymerizations of methyl methacrylate ntUizing poly(l,l,-dihydroper-fluorooctyl acrylate) as a steric stabilizer in snpercritical CO2 were carried out in the presence of helium. Particle size and particle size distribution were found to be dependent on the amonnt of inert helium present. Particle sizes ranging from 1.64 to 2.66 pm were obtained with varions amounts of helium. Solvatochromic investigations using 9-(a-perflnoroheptyl-p,p-dicyanovinyl)julolidine indicated that the solvent strength of CO2 decreases with increasing helium concentration. This effect was confirmed by calcnlations of Hildebrand solubility parameters (Hsiao and DeSimone, 1997). 

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