关键词: 玄武岩纤维, 乙烯基酯树脂, 复合材料, 硅烷偶联剂, 力学性能

Abstract: Fiber-reinforced resin matrix composites have developed rapidly in recent years. Their overall properties are not only related to the properties of resins and fibers, but also closely related to the interface between resins and fibers. When the composite is loaded, the interface will transfer the stress of the matrix to the reinforced fiber in the form of shear stress. Therefore, fiber-reinforced composites require excellent interface phases so that the matrix can effectively transfer load to the fiber. The appropriate modification method can improve the interface and mechanical properties of the composites. The operation steps of silane coupling agent modification are relatively simple, and the fiber will not be damaged during modification. There are hydroxyl groups on the surface of the basalt fiber, so the use of silane coupling agents can build a bridge between the basalt fiber and resin matrix.
In order to improve the interfacial bonding property of the basalt fiber and vinyl ester resin, silane coupling agents KH550, KH560 and A171 with a respective mass fraction of 0.5%, 1.0%, 1.5% and 2% were used to modify the basalt fiber, and basalt fiber-reinforced vinyl ester resin composites were prepared by the molding process. The scanning electron microscope, infrared spectrometer and universal testing machine were used to test and analyze the surface micro morphology and chemical structure of basalt fibers and the mechanical properties of composite materials, and to explore the modification mechanism of silane coupling agents with different kinds and concentrations, providing theoretical support for their application in engineering practice. The research results show that after the basalt fiber is modified by the silane coupling agent, the silane coupling agent is grafted on the surface of the basalt fiber, which makes the surface rough and increases the surface chemical activity of the fiber, forming an interface layer to transmit stress, and improving the bending strength and impact strength of basalt fiber-reinforced composites. The absolute value of Pearson correlation coefficient R of bending strength and impact strength fitting curves is approximately 1 after the basalt fiber is modified by silane coupling agents with different kinds and different mass fractions, which indicates that the fitting curve is approximately a quadratic equation with one variable, showing a trend of first increasing and then decreasing. The basalt fiber modified by silane coupling agents KH550, KH560 and A171 with a mass fraction of 1% has the best interface bonding with vinyl ester resin, and the flexural strength of the modified basalt fiber-reinforced composite is respectively 16.71%, 14.96% and 13.59% higher than that of the unmodified composite; the impact strength increases by 10.13%, 8.84% and 7.41%. With the experimental results taken into consideration comprehensively, the modification effect of KH550 is the largest, followed by that of KH560, and that of A171 is the smallest.
In this paper, basalt fibers were modified by silane coupling agents KH550, KH560, and A171 with different mass fractions, and the mechanical properties of their reinforced vinyl ester resin composites were analyzed to study the modification effect of silane coupling agents, and the best type and concentration of silane coupling agents were given, playing a certain guiding role in improving the interfacial bonding properties and mechanical properties of composites.