Anionic polymerization of isopropenyl t-butyl ketone

Abstract

The authors report model reactions of isopropenyl t-butyl ketone (IPTBK) with several initiators and polymerization with t-butyllithium (tBuLi). Experimental evidence indicates that in anionic polymerization of IPTBK, the molecular weight distribution is narrow ranging from 1.1 to 1.6 while Mn varies from 2,800 to 223,500 and Mn increases with conversion. This is in contrast with anionic polymerization of methy isopropenyl ketone with nBuLi, which gives a bimodal distribution and Mn that are independent of conversion and initiator concentration (8). The model reactions have indicated that side reactions are minimal and that initiation is faster than propagation in the IPTBK/tBuLi system. The cooling and warming experiments along with the model reactions indicate that the growing anion lives long.