42 measured by usual iodine titration method the viscous liquid has the same characteristic absorption waves in ira spectrum and the same u03b4 and strength values in nmr spectrum as those of example 4 so that it is confirmed that it consists of the same structural unit with the polymeric diacyl peroxide of example 4 the polymeric diacyl peroxide has a mean molecular weight of 2 320 n u2245 6 3 determined by a similar manner as in example 1 the same reaction with separation and purification as in example 4 is repeated except that 134 7 g 0 24 mol of 10 potassium hydroxide aqueous solution is used instead of 137 g 0 24 mol of 7 sodium hydroxide aqueous solution to obtain 32 g of a transparent viscous liquid the viscous liquid has an active oxygen content of 4 16 measured by usual iodine method as in example 1 the viscous liquid has the same characteristic absorption waves in ira spectrum and the same u03b4 and strength values in nmr spectrum as those of example 4 so that it is confirmed that it consists of the same structural unit with the polymeric diacyl peroxide of example 4 the polymeric diacyl peroxide has a mean molecular weight of 14 700 n u2245 39 9 determined by a similar manner as in example 1 in a four necked flask equipped with.