1. Styrene is polymerized by free-radical mechanism in solution. The initial monomer and initiator concentration are 1 M (molar) and 0.001 M, respectively. At the polymerization temperature of 60 °C, the initiator efficiency is 0.30. The rate constants at the polymerization temperature are as follows:
Given this information, determine the following:
(a) Rate of initiation at 1 min and at 16.6 h;
(b) Steady-state free-radical concentration at 1 min;
(c) Rate of polymerization at 1 min;
2. Consider a free-radical addition reaction in which there is negligible conventional termination. Instead, growing chains are killed by a derivative chain-transfer reaction:
Where D’ is a stable radical that does not reinitiate polymerization.
a. Obtain the rate expression for this mechanism.
b. Obtain the expression for number-average chain length according to this mechanism.
