Anionic polymerization of N,N‐dialkylacrylamides containing alkoxysilyl groups in the presence of Lewis acids

Abstract

AbstractWith Ph2CHK as an initiator, the anionic polymerization of N‐propyl‐N‐(3‐triisopropoxysilylpropyl)acrylamide (4) and N‐propyl‐N‐(3‐triethoxysilylpropyl)acryl‐amide generated polymers with predicted molecular weights and narrow molecular weight distributions (MWDs) in the presence of Et2Zn or Et3B; however, the resulting polymers obtained in the absence of such Lewis acids had very broad MWDs. The results were ascribed to the coordination of the propagating anionic end to a relatively weak Lewis acid, in which the activity of the end anion was appropriately controlled for moderate polymerization without side reactions. A well‐defined diblock copolymer of 4 and N,N‐diethylacrylamide was also prepared with the binary initiating system of Ph2CHK and Et2Zn, whereas no such block copolymer was prepared by polymerization initiated with 1,1‐diphenyl‐3‐methylpentyllithium, as the propagating anion together with the lithium ion reacted with alkoxysilyl side groups on the poly(4) backbone to produce grafted polymers with high molecular weights. The hydrolysis of the alkoxysilyl side groups of poly(4) in acidic water yielded an insoluble gel. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2754‐2764, 2005