DYNAMICS OF CROSS-LINKED POLYMERS

The local dynamics of randomly branched polymers made by cross-linking of linear chains were considered. Spin echo measurements at two conce ntrations in the semi-dilute regime give a scattered intensity varying as a stretched exponential with time, S(q, t) similar to exp{-(Omega t)(2/3)}, with a characteristic frequency, Omega, proportional to the third power of the wave vector, q. These various dependencies are basi cally the same as for uncross-linked chains and show that the local st ructure of the polymers is by cross-linking.