Preparation and Thermal Insulation Properties of PET /Silica Aerogel Composite Fibers

ABSTRACT

Silica aerogel is a nanostructured material with high specific surface area, high porosity, low density and excellent heat insulation properties. These properties offer exciting applications in thermal fabric. But the weak mechanical properties caused by the hydrophilicity limit its further development and application. In this study, Methyltrimethoxysilane (MTMS) is used as a precursor to introduce methyl groups to induce hydrophobicity in aerogels and ambient pressure drying is used for the preparation of hydrophobic silica aerogels and the optimal preparation conditions are investigated. Meanwhile, silica aerogel particles modified by γ‐Methacryloxypropyltrimethoxysilane (KH‐570) with excellent dispersity and high thermal performance are integrated into polyethylene terephthalate (PET) via the melt blending method, and then processed into PET/silica aerogel composite fibers through melt spinning. The results demonstrated that the hydrophobic silica aerogels prepared via ambient pressure drying process using MTMS as a precursor eliminated the need for post‐synthesis hydrophobic modification, thereby avoiding pollution caused by organic solvents and hydrophobic modifiers. The obtained silica aerogels exhibited excellent hydrophobicity and thermal insulation performance, with a density of 0.14 g·cm ⁻³ , a porosity of 93.6%, a thermal conductivity of 0.032 W·m ⁻¹ ·K ⁻¹ , and a water contact angle of 137.1°. Furthermore, the incorporation of silica aerogel particles into PET fibers reduced the calculated thermal conductivity based on an idealized thermal conductivity model from 0.0899 to 0.0564 W·m ⁻¹ ·K ⁻¹ , corresponding to a 37.3% reduction. These results demonstrate that the PET/silica aerogel composite fibers possess excellent thermal insulation performance. Therefore, the developed composite fibers show great potential for applications in extreme environments where both superior thermal insulation and hydrophobicity are required.