The performance of glass fiber refers to the performance of the fiber under working conditions. It mainly includes physical properties, chemical properties and mechanical properties.
Unlike other natural or artificial organic fibers, glass fibers are smooth cylinders, each of its cross sections is almost a complete circle. This feature makes the small cohesion between the glass fibers, and does not facilitate matrix bonding.
Table 1 Density of glass fiber, carbon fiber and some commonly used textile fibers and metal materials
As shown in the above table, the density of glass fiber is higher than that of organic fiber, but lower than that of ordinary metal, it is about the same density as aluminum. Therefore, maybe it is possible to replace the aluminum-titanium alloy with Glass fiber in the industry. In addition, the density of glass fiber depends largely on its composition. For example, the density of alkali-free glass fiber is generally greater than alkali glass fiber.
The electrical properties of glass fiber depend mainly on the chemical composition of the glass, especially the alkali oxide content. The lower the content, the better the dielectric properties. Alkali-free glass fiber has the lowest dielectric constant (around 6.5), it is widely used in electrical insulation materials.
Glass fiber is an excellent thermal insulation material, its thermal conductivity is very small, especially glass wool products. Therefore, it is commonly used for thermal
insulation, cold insulation and keep warm of buildings and industries. The larger the gap between the fibers, the smaller the density, and the lower the thermal conductivity, that because the thermal conductivity of air is low. Secondly, since the glass fiber is an inorganic material, it is not flammable and has good heat resistance, which is a characteristic that other textile fibers do not have.
Table 2 Breaking strength and elongation of glass fiber, carbon fiber and some commonly used textile fibers and metal materials
| Material type
| Breaking strength（N）
As can be seen from the table, glass fiber has unique properties in the following aspects.
Although glass fiber is made of glass, its breaking strength is much higher than that of the same composition. At the same weight, the breaking strength is 2 to 4 times higher than steel. The title of FRP also came from this.
Glass fiber does not deform due to changes in ambient temperature, and the elongation is only 2% to 3%. Dimensional stability is higher than other textile fibers and metal materials.
Glass fiber has a high hardness , and about 15 times that of nylon. The combination of the hardness of the glass fiber and its inherent brittleness constitutes a prominent low bending resistance, which is not conducive to the textile processing of the glass fiber. By reducing the diameter of the glass fiber, the bending resistance of the fiber can be improved.
- Wear resistance and folding resistance
Wear resistance and folding resistance refer to anti-friction and anti-breaking properties, but both properties of glass fiber are not good. In order to meet the needs of textile fibers, surface treatment is generally used to make the glass fiber soft and wear resistant.
Glass fiber has stable chemical properties, it rarely reacts chemically with the surrounding medium, even good resistance to corrosive chemicals such as acids and bases, and it is stable to most inorganic compounds.
Glass fiber has anti-aging, anti-corrosion, anti-mildew, anti-ultraviolet radiation and other properties. The processing properties of glass fibers can be improved by appropriate surface treatment. In addition, the broken fiber head of the fiber can cause itching if it touches with human body. Since the glass fiber can not be absorbed and decomposed at all, if a person inhales for a long time, it will cause certain damage to the lungs. Furthermore, glass fiber has poor hygroscopicity, very difficult to dye, and very high manufacturing costs.