Polymer Design by Iniferter Technique in Radical Polymerization: Synthesis of AB and ABA Block Copolymers Containing Random and Alternating Copolymer Sequences

Abstract

The iniferter technique was applied to synthesis of the AB and ABA block copolymers containing various random and alternating copolymer sequences. Benzyl N,N-diethyldithiocarbamate (BDC), p-xylylene bis(N,N-diethyldithiocarbamate) (XDC) and 1,2,4,5-tetrakis(N,N-diethyldithiocarbamylmethyl)benzene (DDC) were used as mono-, bi- and tetrafunctional photoiniferters, respectively. The photopolymerizations with BDC and XDC proceeded via a living radical mechanism, and gave soluble mono- and bifunctional polymers (photoiniferters), respectively. However, DDC induced living radical polymerization of styrene with gelation. When various polymers and copolymers obtained by BDC and XDC were used as polymeric photoiniferters, the AB and ABA block copolymers containing random copolymer sequences were obtained in high yields. Similarly the alternating copolymerization of isobutyl vinyl ether with maleic anhydride in the presence of the alternating copolymers such as styrene and diisopropyl fumarate, which were obtained by BDC and XDC, as polymeric photoiniferters was found to give the AB and ABA block copolymers consisting of alternating copolymer sequences. DDC and the polymers and copolymers obtained by DDC could also act as an excellent cross-linking agent.