VAPOR-LIQUID-EQUILIBRIA FOR SOLUTIONS OF DENDRITIC POLYMERS

Vapor-liquid equilibrium data were obtained for dendritic polymer solu tions using a classic isothermal gravimetric-sorption method; the amou nt of solvent absorbed by the dendrimer was measured at increasing sol vent activity. The polymers were polyamidoamine (PAMAM) dendrimers of generations 1, 2, and 4 and benzyl ether dendrimers with different end groups (aromatic rings, dodecyl chains, methyl ester groups, perfluor oalkyl chains) of generations 2 to 6, and two series of benzyl ether l inear polymers that are analogues of the dendrimers. Solvents were ace tone, acetonitrile, chloroform, cyclohexane, methanol, n-pentane, n-pr opylamine, tetrahydrofuran, and toluene. The temperature range was 35 to 89 degrees C. The amount of solvent absorbed by the dendrimers depe nds, sometimes strongly, on the kind of dendrimer end groups. The rela tion between solvent absorption and dendrimer generation number, or mo lecular weight, depends on the solvent-dendrimer system and on tempera ture. Solvent absorption in linear polymers is below that for correspo nding dendrimers, all or in part owing to crystallinity in the linear polymers.