Temperature‐Responsive PLA ‐Loaded PEA / TEGDA Microcapsules for Controlled Acid Release in High‐Temperature Acidizing

ABSTRACT To address the challenges of uncontrolled acid release and high solid residues during high‐temperature acidizing, temperature‐responsive controlled‐release polymer microcapsules were fabricated via photopolymerization using poly (ester acrylate) (PEA)/triethylene glycol diacrylate (TEGDA) as the polymer matrix and polylactic acid (PLA) as the dispersed phase. The effects of temperature on acid‐release behavior, residue formation, and filter cake removal performance were investigated at 100°C, 120°C, and 150°C. The morphology, chemical structure, particle size distribution, and thermal stability of the microcapsules were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), laser particle size analysis, and thermogravimetric analysis (TGA). The prepared microcapsules exhibited spherical morphology with particle sizes mainly distributed between 10 and 50 μm. Temperature‐dependent release tests showed accelerated acid release with increasing temperature, accompanied by structural evolution of the polymer matrix. After aging at 150°C, the residual solid fraction decreased to 5.8% ± 0.5%. Filter‐cake removal experiments further demonstrated a temperature‐dependent increase in removal efficiency, with average removal efficiencies of 58.8% ± 2.2%, 76.0% ± 2.4%, and 89.0% ± 4.6% at 100°C, 120°C, and 150°C, respectively. These results demonstrate temperature‐responsive acidic product release and a reduced gravimetrically recoverable solid fraction under the investigated high‐temperature conditions.