レドックス重合メタクリルポリマー／ブロックコポリマーブレンドのナノ構造と破壊靭性

抄録

Functional all-methacrylate triblock copolymers (BCPs) with a soft middle block chain and hard block chains at both ends were dissolved in methacrylate monomers and then polymerized using redox polymerization. Methyl methacrylate (MMA) and methacrylic acid (MAA) were used as the monomers. In the PMMA matrix without MAA copolymerization, polymerization-induced phase separation occurred in the blend, resulting in the formation of micrometer-sized phase structures. By contrast, in the MAA copolymer matrix, self-assembled nanostructures consisting of curved lamellae, worm-like cylinders, and spherical micelles were formed, depending on the number of functional groups in the hard block chains of the BCPs. The BCP blend with the worm-like cylindrical nanostructure exhibited remarkable fracture toughness. Under loading, cavities formed within the worm-like cylinders near the pre-crack tip. These cavities then transformed into craze-like deformation, forming a large shear yield zone within the polymethacrylate matrix. This was found to be the toughening mechanism.