LIVING TREES - DYNAMICS AT A REVERSIBLE CLASSICAL GEL POINT

The authors discuss the effects of slow, reversible scission of cross-links in polymer networks very close to the 'classical' gel point in a densely pre-entangled system. They predict that for k beta tau varies as >>1, reversible scission has a significant effect on the relaxation process, yielding a terminal time tau approximately=k-1ln( beta tau varies as k). In these expressions, k is the scission rate constant, beta is a geometrical factor (proportional to the number of entanglements per chain in the precursor system), and tau varies as is the disentanglement time for the irreversibly cross-linked system as calculated recently by M. Rubinstein, S. Zurek, T.C.B. McLeish and R.C. Ball.