| Abstract: | The present investigation was undertaken to study further the synthesis of networks with viscoelastic properties. This involves two stages: synthesis of functional polymers with reactive chain ends and selective condensation reaction with polyfunctional crosslinking agents. In order to determine the conditions of crosslinking reaction, a preliminary study was realised on the branched star polymer synthesis. These polymers are obtained by reaction of ω-functional polymer with tri-, tetra-, and pentaisocyanates. Polymers used in this work were polyisoprene, polybutadiene, polystyrene, block copolymers from diene and styrene with hydroxylic end groups. The reaction of the liquid polymer having hydroxylic end groups with isocyanates leads to a branched star polymer with formation of an urethane group, the average branching depending on the functionality of the polyisocyanates. Structures of this star polymer are confirmed by NMR analysis and by determination of the rel. mol. mass. |
