The interaction of two dissimilar polymers in solution

Abstract

The lowest E* value recorded12JJ for high polymers is that of polydimethylsiloxane, namely, 3.6 or 4.3 kcal./mole.This is in keeping with its highly flexible chain.Among the factors contributing to this chain flexibility are ( a ) lack of substituents on every other chain atom, (6) the greater length of silicon-carbon than of carbon-carbon bonds (1.88 versus 1.54 A.), meaning that the methyl groups of polydimethylsiloxane are farther removed from the backbone than are those of polyisobutylene, for instance, and interfere less with rotation about the bonds in the backbone, ( c ) that silicon-oxygen bonds are longer than carbon-carbon bonds, and that, moreover ( d ) the attraction between silicon-oxygen dipoles is considerably reduced through shielding by the methyl groups.References