Composition‐Dependent Differences in Structure and Mechanical Properties of Gels Synthesized by Reversible Deactivation Radical Copolymerization and Free Radical Copolymerization

The effects of polymerization mechanism and polymerization composition on the structure and mechanical properties of gels synthesized by radical copolymerization of monomers and cross-linkers are investigated using a coarse-grained molecular dynamics simulation. The effects of changing the polymerization mechanism from conventional free radical polymerization (FRP) to reversible deactivation radical polymerization (RDRP) depend on the polymerization composition. Due to the change in the number of loop structures depending on the concentrations and reaction rates, the cross-linking efficiency of the RDRP gel is higher at intermediate monomer concentrations than that of the FRP gel, but is lower at low monomer and low cross-linker concentrations and at high monomer concentrations. The influence of the polymerization mechanism on entanglement is almost independent of the polymerization composition, and the number of entanglements is lower in the RDRP gels than in the FRP gels. The stiffness and stretchability of the RDRP gels are lower than those of the FRP gels over a wide range of composition, but at high monomer concentrations, the RDRP gels, which have lower cross-linking efficiency, exhibit higher stretchability than the FRP gels.