Since, the values ofkp,handkp,gare the same (Zkp) in the
solution graft copolymerization[5], it is interesting to examine
if the propagation rate coefficient (kp) of AA obtained from the
solution polymerization at low temperature are fitting forkp,gin
the melt. The data, kp
of AA in aqueous solution at
concentration of 40 wt% and temperature between 2.6 and
28.58C[16] are extrapolated to 130–1708C, and compared
withkp,gin Table 3. Table 3shows that the extrapolated data
are 1 order of magnitude larger than the measured data,kp,g,
which indicates that it may be not entirely justified to use the
data extrapolated from the solution polymerization at modest
temperature to interpret the kinetics behavior in the melt. One
possible reason may be the different viscosity of the reaction
medium. The viscosity of a free radical grafting system in the
melt can be several orders of magnitude (10
2
–10
5
Pa s) higher
than that in solution, and the high viscosity would impart more
effects to the individual reaction step involved in grafting