Synthesis of ultra‐high molecular weight core cross‐linked star (CCS) polymer using high molecular weight spherical nanoparticles and arm‐first method

P (N,N‐Dimethylacrylamide) ‐b‐P (2‐methoxyethyl acrylate) (PDMA‐b‐PMEA) and Poly (poly (ethylene glycol) methyl ether methacrylate) ‐b‐P (2‐methoxyethyl acrylate) (PPEGMA‐b‐PMEA) di‐block copolymer nanoparticles are prepared by RAFT dispersion polymerization in water at 35°C. By changing the degree of polymerization (DP) of PMEA and the solid content of the reaction solution, only spherical nanoparticles are obtained. Using PDMA and PPEGMA as macromolecular chain transfer agents (Macro‐CTA), the actual DP of PMEA block can be up to 11,520 and 17,000, respectively, the size of the obtained spherical nanoparticles can be close to 600 nm, and the molecular weight of the block copolymer can reach 106. Such large spheres may serve as model sterically stabilized particles for analytical centrifugation studies. In the mixed solvent of ethanol and water (1:1, v/v), we synthesize ultra‐high molecular weight CCS polymer by the arm‐first method. Star polymer with such high molecular weight and small particle size can be used for emulsification. P (N, N‐Dimethylacrylamide)‐b‐P (2‐methoxyethyl acrylate) (PDMA‐b‐PMEA) and poly (poly (ethylene glycol) methyl ether methacrylate)‐b‐P (2‐methoxyethyl acrylate) (PPEGMAb‐PMEA) di‐block copolymer nanoparticles are prepared by RAFT dispersion polymerization in water at 35°C. Only spherical nanoparticles are obtained. The actual DP of PMEA block can be up to more than 104. Ultra‐high molecular weight core‐crosslinked star polymer can be prepared by the arm‐first method.