KINETIC-STUDY OF VINYL POLYMERIZATION WITH A NEW OLIGO AZO PEROXIDIC INITIATOR

Oligo opentanoyl-5-peroxy-2,5-dimethyl-n-hexylperoxide), Lu-Ab, was sy nthesized by the interfacial condensation of 4,4'-azobis-(4-cyanopenta noyl chloride) with 2,5-dimethyl-2,5-dihydroperoxyhexane in the presen ce of a base. The molecular weight of the initiator was determined to be 1586 g/mol by gel permeation chromatography (GPC). Oligo-azoperoxid e, Lu-Ab, was characterized by infrared and nuclear magnetic resonance spectroscopies. Styrene and methyl methacrylate were separately polym erized with Lu-Ab at 60 degrees C by free radical low conversion polym erization in order to calculate kinetic parameters. In these units nee ded connection overall rate constants (k) and k(t)/k(p)(2) were found to be 1.86 x 10(-4) L mol(-1) s(-1) and 1.22 x 10(3) L-1 mol s for sty rene; 3.73 x 10(-4) L mol(-1) s(-1) and 0.21 x 10(3) L-1 mol s for met hyl methacrylate, respectively. Lu-Ab is an initiator without chain tr ansfer to initiator, like azobisisobutyronitrile (AIBN) but is only ha lf as effective as AIBN. (C) 1997 Elsevier Science Ltd.