N,N '-dipropyl, N,N '-bis(4-methyl benzene sulfonyl) hydrazide: a new radical source for chain polymerization of vinyl monomers

A new radical initiator N,N ' -dipropyl, N,N ' -bis(4-methyl benzene sulfon yl) hydrazide (DBSH) has been prepared by condensation of N-chloro and sodi um derivatives of N-propyl,4-methyl benzene sulfonamide at room temperature . As a radical initiator DBSH shows interesting properties that, although h omolysis of the N-N band takes place around 52.5 degreesC, only very low po lymerization yields (similar to1.0 %) are obtained below 100 degreesC. At 1 00 degreesC, bulk polymerization of methyl methacrylate proceeds rapidly an d the reaction is almost quantitative in 2.5 h. This can be attributed to s tability of the sulfamidyl radicals to some extent. Radical initiation effi ciency of DBSH is about 0.16 and gives high molecular weight of polymers at that temperature. Presence of sulfamidyl groups in polymer chain ends have been confirmed by NMR and elementary analysis. In the study, for radical initiation ability of DBSH in bulk polymerization of methyl methacrylate and styrene monomers has been investigated in vario us time, temperature conditions, (C) 2001 Elsevier Science Ltd. All rights reserved.