Synthesis and Microphase Separation of PS‐b‐P(MA‐alt‐St) Block Copolymers and Their Ionomers for the Design of Polymer Crystallization Nucleation Agents

Several well‐controlled polystyrene‐block‐poly(styrene‐alt‐maleic anhydride) (PS‐b‐P(St‐alt‐MA)) functionalized block copolymers (BCs) and their sodium salt ionomers with different block ratios and molecular weights are synthesized through two‐step reversible addition–­fragmentation chain transfer (RAFT) polymerization. The atomic force microscopy (AFM) images and differential scanning calorimetry (DSC) results reveal that the prepared BCs and their ionomers microphase separate into various nanostructures depending on the block ratios. By taking advantage of the formation of amphiphilic nanostructures via the microphase, the block ionomers serve as nucleation agents to improve the crystallization rate of poly(ethylene terephthalate) (PET). The crystallization behavior of PET upon the addition of block ionomers is investigated isothermally and non‐isothermally by DSC. The results show that the block ionomers can effectively accelerate the crystallization rate of PET, which strongly depends on the molecular weights and block ratios