Fiberglass extruded profiles are currently a widely used material, which can be used to make various products such as guardrails, grilles, cover plates, square tubes, etc. In the production process of fiberglass extruded profiles, different diameters can affect their performance. So, what is the diameter requirement for fiberglass extruded profiles? Let's take a look together.
In the process of producing glass fiber, changing the melting temperature, leakage plate aperture, drawing temperature, and drawing speed of the glass fiber raw material can control the diameter of the glass fiber. Previously 9-10 μ The glass fiber of m is often used as a reinforcing material for composite materials, and now it is gradually being used with a diameter of 13-18 μ M's fiberglass.
In theory, the finer the diameter of glass fiber, the higher its strength. However, in actual production, the strength of glass fiber is much lower than the theoretical value, due to the formation of many micro cracks on the surface of the single wire during the drawing process. Liang Zhongquan et al. [7] have shown that when the diameter of glass fibers is between 9-13 μ When the range of m changes, the tensile fracture strength of high-strength glass fiber precursor remains basically stable. However, as the diameter of the glass fiber further increases, the specific surface area and surface activity of the glass fiber decrease, resulting in a significant reduction in the amount of adsorbent on the surface of the glass fiber, leading to a significant increase in surface defects and a decrease in strength. According to the principle of fiber reinforcement, the reinforcing effect of fibers can only be fully exerted when the fiber length is above the critical length. In theory, the minimum length of reinforced fibers is 50-100 times the diameter. However, as the fiber length continues to increase, the tensile strength significantly decreases.
Research has shown that with the increase of fiber length, the reinforcement efficiency of fibers improves. When the fiber length exceeds 12mm, the reinforcement effect of fibers on various properties of composite materials basically reaches the best. Although the number of microcracks in fibers increases with the increase of fiber length, resulting in a decrease in fiber strength, long fiber fiberglass exhibits better performance than short fiber fiberglass in terms of rigidity, compressive strength, bending strength, creep resistance, impact strength, etc. There are three ways for fiber composite materials to absorb impact strength: fiber fracture, fiber pull-out, and resin fracture. As the fiber length increases, fiber extraction consumes more energy, which is beneficial for improving impact strength. In addition, the ends of fibers are prone to stress concentration, which is the initiation point of crack growth. Therefore, long fibers with fewer ends can also improve the material's impact strength.
