Monofunctional monomers such as hydroxyalkyl (meth)acrylates can form crosslinked polymer in anionic polymerization. This unusual phenomenon relates to a plural reactivity of such type of monomers and their ability to be polymerized by the Michael addition mechanism with the formation of isomerized heterochain fragments of backbone as well as by anionic polymerization with the formation of carbon chain fragments of the main chain. This combination of reaction mechanisms results in the formation of highly branched polymer. Besides these reactions, simultaneous anionic polymerization of hydroxyalkyl (meth)acrylates, an intensive interchain exchange reaction leading to redistribution of the end functional groups and formation of polyester-ether di(meth)acrylate macromolecules result in crosslinking of the generated polymer.