What are the changes in the mechanical properties of glass microfiber under high temperature environments and what are the corresponding countermeasures?
Release Time : 2026-01-09
Glass microfiber, an inorganic non-metallic material drawn from molten glass, is widely used in construction, transportation, and electronics due to its high strength, corrosion resistance, and excellent insulation. However, under high-temperature environments, its mechanical properties change significantly due to factors such as molecular structure alterations, differences in thermal expansion, and oxidative corrosion, thus affecting the material's service life and structural safety. A deep understanding of these changes and the implementation of targeted measures are crucial to ensuring the reliable application of glass microfiber in high-temperature scenarios.
Under high-temperature environments, the molecular structure of glass microfiber faces its first challenge. The silicon-oxygen bonds in its amorphous network gradually loosen at high temperatures, leading to reduced crystallinity, changes in grain size, and even localized melting. This change in microstructure weakens the intermolecular bonding forces, reducing the fiber's strength and stiffness. For example, while the strength of ordinary E-type glass microfiber does not decrease significantly at 200℃, it undergoes volume shrinkage; when the temperature rises to 550℃, its tensile strength may drop to half of that at room temperature. Furthermore, prolonged exposure to high temperatures can trigger the propagation of microcracks on the fiber surface, further accelerating performance degradation.
Thermal expansion is another significant factor affecting the mechanical properties of glass microfiber at high temperatures. Although the coefficient of thermal expansion of glass microfiber is lower than that of metals, it still generates thermal stress due to dimensional changes at high temperatures. When the coefficients of thermal expansion of the fiber and the matrix material (such as resin) do not match, stress concentration occurs at the interface, leading to debonding or the initiation of microcracks. For example, in glass microfiber-reinforced polypropylene composites, increased temperature softens the matrix and reduces the elastic modulus, while the thermal stress between the fiber and the matrix weakens load-bearing capacity, ultimately resulting in a decrease in modulus and strength.
Oxidation and corrosion are another contributing factor to the performance degradation of glass microfiber at high temperatures. In the presence of oxygen or other oxidants, oxidation reactions may occur on the fiber surface, generating a low-strength oxide layer, leading to performance degradation. For example, the corrosion of alkali-free glass microfiber in acidic media is essentially a hydrolysis process of metal ions; the looser the network structure, the easier ion migration and the worse the corrosion resistance. Furthermore, high temperatures accelerate the erosion of fibers by chemical media, damaging their surface structure and further shortening their service life.
To address performance changes under high-temperature environments, the temperature resistance of glass microfiber can be improved through material modification. For example, adding zirconium oxide, titanium oxide, or alumina (10%-15%) to the glass composition can increase heat resistance to 700-800℃; using high-silica or quartz fibers (with a silica content of 91%-99%) allows for long-term use above 1000℃. Furthermore, coating the surface with high-temperature resistant silane coupling agents or ceramic coatings can form a protective barrier, reducing oxidation and corrosion and optimizing short-term thermal stability.
Optimizing composite material design is another effective way to address high-temperature challenges. By adjusting the matching of the thermal expansion coefficients of the fiber and the matrix, interfacial thermal stress can be reduced, preventing debonding and microcracks. For example, in glass microfiber reinforcing polymers, selecting a resin matrix with a low thermal expansion coefficient, or improving the bonding performance between the fiber and the matrix through interfacial compatibilizers, can improve the high-temperature stability of the composite material. In addition, using lamination or weaving structures can disperse thermal stress and enhance overall resistance to deformation.
Strictly controlling operating conditions is crucial to ensuring the high-temperature performance of glass microfiber. For short-term high-temperature exposure scenarios (such as temporary equipment overheat protection), ordinary E-type glass microfiber can be used continuously at 300℃ for 1-2 hours with a strength decrease controlled within 15%. However, for long-term high-temperature operating systems, high-silica or quartz fibers with superior temperature resistance should be selected. Simultaneously, the fibers should be avoided in humid, sulfur-containing, or alkaline environments to reduce the risk of crystallization and corrosion. For example, in industrial pipeline insulation layers, if the system may experience transient overheating, temperature monitoring and heat dissipation mechanisms should be incorporated, and a composite structure should be formed using high-temperature resistant metal foil or ceramic fiber layers to improve overall thermal insulation efficiency.
From molecular structure relaxation to thermal stress concentration, from oxidation corrosion to operating condition control, the changes in the mechanical properties of glass microfiber under high-temperature environments involve multiple dimensions. Through material modification, composite structure optimization, and precise operating condition management, its temperature resistance and reliability can be significantly improved. In the future, with the research and application of special glass microfibers (such as alkali-resistant and high-modulus types), the performance boundaries of glass microfibers in high-temperature fields will be further expanded, providing better solutions for high-end equipment manufacturing and extreme environment engineering.