Targeted Copolymerization in Amorphous Regions for Constructing Crystallizable Functionalized Copolymers

Heavily damaged or disappeared crystallizability caused by nonselective chemical binding of functional units is a universal and challenging issue for random functionalized copolymers. Herein, we propose a temperature-controlled targeted copolymerization that can selectively activate the amorphous region segments of polymers and directionally copolymerize the functional units into this region while retaining the regular segments and crystallizability of the original crystalline region. A flame-retardant functional monomer and typical semicrystalline polyester are chosen to verify our state-of-the-art targeted copolymerization approach. Compared with the corresponding random copolymers, the resulting microblock copolymers exhibit a much higher crystallinity and faster crystallization rate while keeping other functionalities. Even at a high functional unit content (16.7 mol %), targeted copolymerization can endow copolymers with good crystallinity, while the corresponding random copolymer is totally noncrystallizable. Hence, targeted copolymerization chemistry provides a pioneering opportunity to achieve functionalization and maximum retention of crystallization ability at the same time, allowing purposeful tailoring of macroscopic performance by precisely regulating the sequential distribution of microstructure units.