Core Viewpoint - The research team from Qingdao University of Science and Technology has made significant progress in the design and synthesis of biodegradable and closed-loop recyclable polymer materials, providing a new pathway for plastic recycling [1] Group 1: Environmental Impact - Traditional plastics are non-degradable under natural conditions, leading to severe environmental pollution issues [1] - Developing recyclable and biodegradable aliphatic polyester materials is considered an effective solution to plastic pollution [1] Group 2: Research and Development - The team has developed an organic aluminum catalyst that successfully achieves the chemically selective ring-opening polymerization of α-methylene-δ-valerolactone [1] - This catalyst can be prepared in one step using commercially available alkyl aluminum and antioxidants without the need for purification [1] - The catalyst demonstrates excellent proton tolerance, allowing for the production of polyester polyols with controllable molecular weight and end groups even with 100 equivalents of alcohol [1]