2024 Volume 45 Issue 1 Pages 13-23
Polymeric nanophase systems that undergo a phase transition in response to pressure changes are known as "baroplastic," a term coined following pioneering research by Professor Anne M. Mayes et al. at the Massachusetts Institute of Technology. More than a quarter of a century has passed since their theoretical and experimental elucidation of this phenomenon. Taniguchi and Mayes discovered that a block copolymer consisting of a poly(ε-caprolactone) derivative with a glass transition temperature below room temperature, and a polylactide with a higher transition point, undergoes a reversible phase transition from a phase-separated or solid state to a miscible or melt/solid state under pressure at ambient temperature. This polymeric material, owing to its pressure-induced plasticity, can be formed under pressure at low temperatures as low as room temperature, achieving both energy-saving molding with reduced CO2 emissions and enhanced recyclability by suppressing thermal decomposition during processing. The low environmental impact of the degradable block copolymers draws attention as a novel high polymeric material. In this review, a series of research on the design, properties, and functions of degradable baroplastics are presented.