The present research aims to investigate the chemical and morphological properties of the methylated silica xerogels produced via the co-gelation approach combined with surface silylation. In the sol–gel synthesis, methyltrimethoxysilane (MTMS) and tetraethylorthosilicate (TEOS) were utilized as silica precursors and trimethylchlorosilane (TMCS) served as a silylating agent. Structural changes were observed depending on the MTMS/TEOS molar ratio and on the post-synthesis-performed surface silylation of the xerogels. Post-synthesis silylation plays a critical role in the exchanging of the surface silanols with methyl groups, preserving the monolithic form. The morphological and structural changes were followed by SEM, ²⁹Si-MAS-NMR, FTIR spectroscopy, nitrogen porosimetry, and contact angle measurements. The results have shown significant structural variations depending especially on the MTMS content. With an increasing MTMS content, the morphology of the samples has changed from a micro/mesoporous texture to a meso/macroporous texture. A higher degree of methyl substitution has been achieved for the silylated samples both confirmed by the FTIR and ²⁹Si-NMR results. On the other hand, only the samples with a high MTMS content could preserve their structural integrity after evaporative drying, and all have exhibited a high degree of hydrophobicity with θ > 140°.

Due to its high pore size and low density, amine‐modified silica aerogel (XSA) is an excellent candidate for the secondary reinforcement material of polymer matrix composites. In this study, the mechanical, thermal, and morphological properties of amine‐modified silica aerogel‐reinforced aramid/epoxy composite (EAFS) produced by the hand lay‐up method were investigated. According to the resin weight, 1 wt.% (EAFS‐1), 2 wt.% (EAFS‐2), and 3 wt.% (EAFS‐3) XSA reinforcements were dispersed into the epoxy resin by ultrasonic mixer. Tensile, three‐point bending, compression, and shear tests were performed to determine the mechanical properties, while thermal properties were determined by dynamic mechanical analysis and thermogravimetric analysis. The mechanical properties demonstrated an upward trend up to EAFS‐2, after which a decline was observed at EAFS‐3. Tensile strength, modulus of elasticity, flexural strength, flexural modulus, and compressive strength of EAFS‐2 increased by 20.43%, 30.91%, 10.09%, 24.01%, and 3.62%, respectively, compared to EAFS‐0. Furthermore, the incorporation of XSA reinforcement resulted in a delay in the onset and endset of the degradation temperature.