LINEAR VISCOELASTIC BEHAVIOR OF DENSELY GRAFTED POLY (CHLOROETHYL VINYL ETHER)-G-POLYSTYRENE COMBS IN THE MELT

We have measured the linear viscoelastic behavior in the melt of two densely graftedpoly~chloroethyl vinyl ether!-g-polystyrene comb polymers. Both samples have a backbone ofapproximately 800 ethyl vinyl ether monomers and the fractions of grafted backbone monomers are98% and 10%, respectively. The viscoelastic behavior shows remarkable features. The combpolymer with the highest grafting density shows a power law behavior over five orders of magnitudein frequency. The power law can be understood through a ‘‘Rouse-like’’ motion of the entire chainswith an apparent friction coefficient coming from the fast Rouse dynamics of the short grafts.Alternatively, the same behavior can be described as the signature of a ‘‘fluctuating’’ physical gel.The less densely grafted comb polymer has a more complex behavior. © 2003 The Society ofRheology.