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.

Transcribed Image Text:

ka kp 1.2x10-5 S-1 176 M-1 S-1 kt = 7.2x107 M-¹ S-1 k₂ Px +D-Px + D ka kp 1.2x10-5 S-1 176 M-1 S-1 kt = 7.2x107 M-¹ S-1 k₂ Px +D-Px + D

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1 a The rate of initiation at 1 min is calculated as follows Theref... View the full answer