Synthesis of Polyether\nBlock Copolymers from 1,2-Epoxybutane\nand AEO<sub><i>n</i></sub> and Comparative Study of Physicochemical\nand Application Properties before and after the Synthesis

In this study, the AEO<sub><i>n</i></sub>BO<sub>2</sub> series of block polyoxybutenol ethers\nwas synthesized by\ncombining\nthe AEO series of polyoxyethylene and preparing 1,2-epoxybutane (BO)\nblock polyether using a semicontinuous method. The synthesis was performed\nby HPLC, MALDI-TOF-MS, FT-IR, and <sup>1</sup>H NMR for structural\nanalysis. The interaction parameters and surface tension of the systems\nbefore and after synthesis were studied using surface tension meter.\nThe diffusion process of the systems before and after synthesis was\nstudied using a KRÜSS bubble pressure tensiometer. The surfactant\nproperties of AEO<sub><i>n</i></sub> and AEO<sub><i>n</i></sub>BO<sub>2</sub> were evaluated by static and dynamic\nsurface tension measurements. Each system formed a saturated adsorption\nlayer in a water solution. The critical micelle concentration decreased\ndramatically after the introduction of BO groups, and the diffusion-adsorption\nprocess was consistent with the kinetic mechanism of hybrid diffusion.\nThe microscopic self-assembled aggregate micellar behavior of all\nthe systems was investigated using DLS, TEM, and SEM. The micellization\nprocess in all systems was spontaneous and enthalpy-driven, forming\nspherical aggregates, with the BO block reducing the aggregate diameter\nof the feedstock from 220.06 nm to about one-third of 80.02 nm. In\naddition, the dynamic contact angle, application, and physicochemical\nproperties such as foaming and foam stabilization of each system were\ninvestigated. The contact angle was reduced from 70 to 50° at\n120 s of stabilization, with a foam volume of 80 mL in all systems\nat 200 s. However, the AEO<sub><i>n</i></sub>BO<sub>2</sub> showed accelerated foam decay at 500 s, with an increase in the\ncontact angle from 70 to 50° at 200 s, but the AEO<sub><i>n</i></sub>BO<sub>2</sub> showed accelerated foam decay at 500\ns, with a decrease in the contact angle from 70 to 50° at 120\ns stabilization. At 200 s, the foam volume of all systems was 80 mL,\nbut AEO<sub><i>n</i></sub>BO<sub>2</sub> showed an accelerated\nfoam decay process, which shows that the BO group can accelerate the\nfoam decay, and the comparative results show that the BO group can\nalso optimize other application properties and physicochemical properties.