• Esterification of xanthan gum with polystyrene maleic anhydride creates an interpenetrating polymer network that significantly enhances shear resistance, overcoming the limitations of hydrogen-bonded double-helix structures.
• The optimal mass ratio of xanthan gum to SMA (5:3) yields a modified gel with viscosity of 1578.8 mPa·s at 4 s⁻¹ and 100.7 mPa·s at 383 s⁻¹, more than doubling shear resistance compared to unmodified XG.
• The introduced ester bonds strengthen molecular interactions, enabling the gel to withstand strong mechanical stress, thus preventing plastic deformation in gel ink applications.
• This work provides a novel approach for developing high-performance gel inks and offers theoretical insights into the rheological behavior of non-Newtonian fluids.