Free Radical Polymerization of Styrene

Question

Free radical polymerization

Styrene is polymerized by free radical polymerization in solution. The initial monomer and initiator concentration are 1 M (mol L^-1) and 0.001M, respectively. At the polymerization temperature of 60°C, the initiator efficiency is 0.30. The rate constants at the polymerization temperature are as follows:

k_d = 1.2*10^-5 s^-1

k_p= 176 M^-1 s^-1

k_t= 7.2*10⁷ M^-1s^-1

Given this information determine the following

(a) Rate of initiation at 1 min and 16.6 min

(b) Steady state free radical concentration

(c) Rate of polymerization at 1 min

(d) number-average degree of polymerization at 1 min

(e) Average free-radical lifetime, τ, at 1 min, where τ is defined as the radical concentration divided by the rate of termination

(f) Why is the information to determine the rate of polymerization and number-average degree of polymerization at 1 min important? What will change if the polymerization has been carried out for several hours already? Give qualitative answers?

(g) To what percentage is the molecular weight reduced at a polymerization time of 1 min when we add a chain transfer agent (0.001 M) with a chain transfer constant of C_s= 40. How would this change if we polymerize over several hours to 100% monomer conversion? Give a qualitative answer?

Summary

The question belongs to Chemical Engineering and it is about free radical polymerization. In this question, styrene is polymerized with free radical polymerization. Several question about free radical polymerization have been answered in the solution in detail.

Total Word Count 238