The effect of the polymerization mechanism on the microstructure of chains and the rheology of polyacrylonitrile solutions

The analysis of theoretical published data and our experimental data makes it possible to assume that the main difference between polyacrylonitriles prepared via emulsion and solution polymerization appears at the stage of synthesis. This difference is likely related to the freezing of the segmental mobility of strongly sorbed two-dimensional chains that grow in a reaction gap of the latex polymer-monomer particles that is narrow in comparison to the undisturbed spectrum of relaxation times of the three-dimensional entanglement network in the volume of polymerization solution. This factor is responsible for an increased concentration of long-chain branches in polyacrylonitrile formed in solution and, correspondingly, marked retardation of the viscous flow of concentrated polyacrylonitrile solutions.