A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form water-soluble hyperbranched poly(N,N-ethylidene bis(N-2-chloroacetyl acrylamide))s (HPECA) through atom transfer radical polymerization/self-condensing vinyl polymerization method in the presence alkyl chlorine/CuCl/2,2-bipyridine activation system which can effectively suppress the gelation formation. 1H-NMR spectra and dual detector size exclusion chromatography proved the hyperbranched structure indisputably, and the degree of branching was determined by the detailed analyses of 1H-NMR spectra. The trend of the degree of branching was in consistent with the result of Mark-Houwink exponent a. The experiment results suggested that the conversion was 67%, Mw = 13.2 ? 104, Mark-Houwink a = 0.282 and the degree of branching = 64% when the reaction temperature was 120 oC, reaction time = 168 h and N,N-ethylidene bis(N-2-chloroacetyl acrylamide):Cu(I) = 50:0.62.
Li-bin BaiRong-rong ZhengWen-liang LiYong-gang Wu巴信武Hai-jun Wang
The novel hyperbranced polymers containing reductive groups were successfully prepared and characterized using redox/reversible addition fragmentation chain transfer(RAFT)/self-condensing vinyl polymerization(SCVP) method. Several redox initiating chemicals such as Cu(III)/―CONH2, Ce(IV)/―CONH2 and Ce(IV)/―OH were chosen to increase the free radical generating rate, and the chain transfer agent(CTA) was used to reduce the molecular chain propagating rate, in order to obtain polymers with high degree of branching. Detailed analyses based on the molecular weight, ? value and the degree of branching of polymers(DB) obtained from 1H-NMR spectra and multi detector size exclusion chromatography(MDSEC) suggested the acquiring of hyperbranced polyacrylamides with Cu(III)/―CONH2 and Ce(IV)/―CONH2 as initiator in the presence of the CTA. Meanwhile, the as-prepared poly(N-hydroxymethyl acrylamide)(PNHAM) with higher DB value(0.48) proved that using Ce(IV)/―OH as the initiator could increase the free radical generating rate and diminish the gap between the propagating rate and the initiation rate during the reaction procedure. In addition, the effect of oxidant concentration on the Mark-Houwink index(?) value and the DB was also studied.
