-
[Hiementz-369], (6.33)
is the kinetic chain length.
- it is ratio of the number of propogation steps to rate of
initiation, regardless of the mode of termination
Hmmm... does this literally
translate that we are taking the ratio of a countable number over
a variable--possibly...
- [Hiementz-369] the overbar signifies that the quantity is an average
- The term
is the kinetic chain length with chain
transfer included.. {Compare 6.82 to 6.33!} Notice on p. 389 of Hiementz how the term R(tr),
which is the rate of chain transfer, goes into the denominator, and
thus brings about a decrease in the value of
.
- The k values are the rate constants
{discussion starts on [Hiementz-356] with the Arrhenius equation}
for the various chain reactions
that occur,
for the termination reaction,
for the
propagation reaction, and
for the transfer reaction. (Hiementz-389)
implies t-->termination and tr-->transfer
- The summation in the denominator is a sum over five terms, all of
which are shown in equation 6.84 of Hiementz (p. 390.)
The term [M] refers to monomer concentration, and the term [M.]
refers to radical concentration (including all polymer chains with
a radical at a chain end.)
Billmeyer
denotes kinetic chain length with then symbol
and discusses
how if termination is only by combination, then the degree of polymerization
is
.
If termination is only by disproportionation, then the
degree of polymerization is equal to
.
He then closes by stating the
following:
rate of growth
Degree of polymerization = Summation ----------------------
rates of termination
by all processes
The ideas needed to build this equation start on Hiementz 345,
the beginning of
CHAPTER 6: ADDITION OR CHAIN-GROWTH POLYMERIZATION. Sorry child, but
you have a
of reading ahead of you...
