R7.1 Polymerization

Rate of
disappearance
of monomer
Rate of formation of
dead polymers
Monomer
balance
Initiator
balance
367
Using Equation (R7.1-14) to substitute for
monomer is
The rate of disappearance of monomer,
agation, :
r
p
�rM � k p M R �
�r M
j�1
Finally, the net rate of formation of dead polymer
r P j
The rate of formation of all dead polymers is
rP
� 0.5kta(
R�)
2
R7.1.3 Modeling a Batch Polymerization Reactor
Chap.
(R7.1-15)
R�,
the rate of disappearance of
(R7.1-16)
�rM,
is also equal to the rate of prop-
Pj
by addition is
(R7.1-17)
To conclude this section we determine the concentration of monomer as a
function of time in a batch reactor. A balance on the monomer combined with
the LCA gives
�
A balance on the initiator I2
gives
dM
------- � k p M ∑ R j � k p MR�
�
dt
Integrating and using the initial condition
tion of the initiator concentration profile:
�
�
�
j
k p MR�
k p M 2k0
( I2)
f
� --------------------
r p
0.5k ta
r P
� �rM
�
k�j�1
�
k�1
�
�
j�1
r P j
� dI2 ------- �
k0 I2 dt
k
t
Rk
R j�k
k
p
M 2k0
( I2)
f
--------------------
k
t
(R7.1-18)
I2
� I20
at t � 0, we obtain the equa