Cast nylon, also known as monomer cast nylon, abbreviated as MC nylon, is one of the excellent engineering plastics. In addition to the commonalities of nylon, it also has the advantages of low polymerization temperature, simple process, high crystallinity, large molecular weight and uniform distribution, low density, good mechanical properties, shock absorption and wear resistance, self-lubricating, corrosion resistance, and wide temperature range for use. However, ordinary MC nylon has disadvantages such as poor low-temperature toughness and poor dimensional stability. Therefore, research on MC nylon reinforcement, toughening, friction reduction, and anti-static is relatively active both domestically and internationally, including the use of glass fiber reinforcement.
The performance of composite materials largely depends on the interfacial bonding state between the reinforcement and the matrix. Surface treatment with silane coupling agent is to firmly bond two materials with vastly different properties that are difficult to bond through chemical or physical actions. Treating the surface of glass fibers with coupling agents can not only protect the fibers from wear, but also provide a good interface for the bonding between glass fibers and polymer matrix, thereby improving the performance of composite materials.
Different silane treatments on glass fibers have a significant impact on the mechanical properties of the material. The bending strength, tensile strength, and impact strength of glass fiber without coupling agent treatment are all reduced compared to pure nylon samples. Silane coupling agent combines nylon matrix with glass fiber through chemical bonds, completing the coupling between two materials with different chemical properties, thereby improving the interfacial strength. As the amount of silane gradually increases, the mechanical properties of the material will rapidly improve. When the amount of silane exceeds a certain value, the glass fiber will have a significant strengthening effect on the nylon matrix; Only when the amount of silane is moderate can it have a reinforcing effect on MC nylon composite materials.
When untreated glass fiber is used as a reinforcing material, it not only does not improve the performance, but also reduces the performance of MC nylon composite materials. By using properly processed glass fibers for reinforcement, the mechanical properties of composite materials have been significantly improved, indicating that surface treatment of glass fibers plays a crucial role in the performance of composite materials.
Untreated glass fibers not only fail to form a good interface bond with the nylon matrix, but also leave gaps at the interface between the glass fibers and the matrix, resulting in an overall decrease in the load-bearing capacity of the matrix. After treatment with a coupling agent, the interface between the glass fiber and the nylon matrix is well bonded, no longer a weak link in the composite material. There is no glass fiber pulling out at the tensile fracture surface, and the fracture surfaces of the glass fiber and the nylon matrix are in the same layer. The matrix transfers the load it bears to the glass fiber through the interface, exerting the reinforcing effect of the glass fiber.
