Polymerization of acrylamide with persulfate–thiomalic acid initiator

The redox system of potassium persulfate–thiomalic acid (I₁–I₂) was used to initiate the polymerization of acrylamide (M) in aqueous medium. For 20–30% conversion the rate equation is where R_p is the rate of polymerization. Activation energy is 8.34 kcal deg^?1 mole^?1 in the investigated range of temperature 25–45°C. M_n is directly proportional to M] and inversely to I₁]. The range of concentrations for which these observations hold at 35°C and pH 4.2 are I₁] = (1.0–3.0) × 10^?3, I₂] = (3.0–7.5) × 10^?3, and M] = 5.0 × 10^?2–3.0 × 10^?1 mole/liter.