Morphological regulation of degradable porous polymers prepared from high internal phase emulsions for sound and organic solvent absorption

The low melt strength of degradable polymers makes the preparation and pore structure manipulation of degradable porous polymers challenging, limiting their widespread utilization. Herein, we report the adoption of a high internal phase emulsion (HIPE) templating method to prepare degradable polymer porous materials with distinct characteristics, such as high porosity, a multiscale porous structure, and degradability. The prepolymer employed as the continuous phase was prepared by grafting degradable polycaprolactone onto 2-ethyloctyl acrylate. Subsequently, the viscosity of the oil phase and the density difference and interfacial tension between the oil and water phases were adjusted via the type and concentration of the diluting solvent. The porosity, pore structure, and degree of pore interconnectivity in the polymerized HIPE were adjusted by considering the physicochemical properties of the diluent and their influence on the oil-water partition at the HIPE interface. Additionally, the mechanisms underlying cavity and window formation in the prepared degradable polymer porous materials were explored. The prepared materials exhibited good sound absorption performance in the frequency range of 3000-4000 Hz, excellent organic solvent absorption capacity, and underwent rapid hydrolysis, with a mass loss of approximately 30% within the first 3 days, which escalated to approximately 80% within 1 month. The study findings provide a valuable reference for the preparation and structural regulation of degradable polymer porous materials, thereby fostering their future applications.