Synthesis and Characterization of Large-Core Star Polymers and Polymer Networks: Effects of Arm Length and Composition of the Cross-Linking Mixture

摘要

Large-core star polymers (LCSPs) and polymer networks were prepared using sequential group transfer polymerization (GTP) for the synthesis of linear poly(methyl methacrylate) (polyMMA) arms, followed by their cross-linking using a mixture of MMA monomer and ethylene glycol dimethacrylate (EGDMA) cross-linker. High monomer/cross-linker molar ratios and short arms favored the formation of polymer networks, whereas the opposite conditions favored the formation of LCSPs. LCSPs presented two populations: star polymers and covalently linked star polymer aggregates. The size of the non-aggregated starpolymers, and the size and fraction of the star polymer aggregates passed through a maximum as the amount of the monomer in the cross-linking mixture increased. The degrees of swelling in tetrahydrofuran (THF) of the networks, the sol fraction extracted from them, and the percentage of linear polymer in the sol fraction increased as the degree of polymerization of the arms increased.