<p>This study explores the effects of incorporating 2-hydroxypropanoic acid as a plasticizer, along with vacuum application, to enhance the properties of cellulose propanoate ester membranes, making them more suitable as porous materials. Scanning electron microscopy (SEM) revealed a substantial increase in pore formation within 2-hydroxypropanoic acid-modified membranes, which can be attributed to the plasticizer's role in enhancing polymer flexibility and reducing intermolecular forces. Fourier transform infrared spectroscopy (FT-IR) analysis indicated chemical shifts, including changes in carbonyl absorption peaks, signifying a decrease in intermolecular interactions. Thermogravimetric analysis (TGA) demonstrated that the inclusion of 2-hydroxypropanoic acid lowers the pyrolysis onset temperature, suggesting modified thermal degradation characteristics. Notably, porosity and air permeability testing showed a significant increase in performance, with porosity reaching 92.8%, confirming the plasticizer’s effectiveness in promoting pore development. This comprehensive evaluation highlights the potential of cellulose propanoate ester membranes modified with 2-hydroxypropanoic acid as high-performance materials. The study provides insights into the impact of plasticizers on polymer membrane properties, emphasizing applications in energy storage. </p> Graphical abstract <p>The significant increase in porosity, reaching up to 92.8%</p>