1. Taking all the parameters into account,
Then
Consider the polymerization of styrene initiated by di-t-butyl peroxide at 60°C. For
solution of 0.01 M peroxide and 1.0 M styrene in benzene, the initial rates of initiation
and polymerization are 4.0 10-11 and 1.5 10-7 mol L-1 s-1, respectively. Calculate
the values of (fkd), the initial kinetic chain length, and the initial degree of
polymerization. Indicate how often on the average chain transfer occurs per each
initiating radical from peroxide. What is the breadth of molecular weight distribution
that is expected, that is, what is the value of X w / X n ? Use the following chain transfer
constants:
CM = 8.0 10-5
Cl = 3.2 10-4
Cp = 1.9 10-4
Cs = 2.3 10-6
Solution:
a. Calculating value of fkd
Ri 4 10−11
Ri = 2 fkd I o fkd = = = 2.0 10−9
2 I o 2 0.01
fkd = 2 10-9
Then
Consider the polymerization of styrene initiated by di-t-butyl peroxide at 60°C. For
solution of 0.01 M peroxide and 1.0 M styrene in benzene, the initial rates of initiation
and polymerization are 4.0 10-11 and 1.5 10-7 mol L-1 s-1, respectively. Calculate
the values of (fkd), the initial kinetic chain length, and the initial degree of
polymerization. Indicate how often on the average chain transfer occurs per each
initiating radical from peroxide. What is the breadth of molecular weight distribution
that is expected, that is, what is the value of X w / X n ? Use the following chain transfer
constants:
CM = 8.0 10-5
Cl = 3.2 10-4
Cp = 1.9 10-4
Cs = 2.3 10-6
Solution:
a. Calculating value of fkd
Ri 4 10−11
Ri = 2 fkd I o fkd = = = 2.0 10−9
2 I o 2 0.01
fkd = 2 10-9
