芳纶纤维与树脂基体改性对复合材料剪切性能的影响

The surface inertness of aramid fiber will affect the wetting property and interface bonding strength between aramid fiber and resin, so the application of aramid fiber composite in aviation, aerospace, power transmission and other fields is limited. In order to compare the effects of fiber surface modification and resin matrix modification on the interlayer shear properties of aramid fiber composites, the effects of different modification techniques and treatment processes on the surface etching of aramid fiber were studied by combining optical and mechanical testing methods. The results show that acetic anhydride chemical etching can affect the surface groups of aramid fiber and increase the surface roughness. After thermal oxidation etching treatment, the surface roughness increases significantly, with obvious "gully" shape. However, when the chemical etching time of acetic anhydride is more than 6 h, and the thermal oxidation etching time is more than 4 min, the internal structure of the fiber is damaged, and the interlayer shear performance of the composite is reduced. After ultrasonic impregnation treatment, the surface roughness of the fiber increases to a certain extent, the gas attached to the fiber surface would be discharged, and the modification effect tends to be stable after more than 20 min. The use of coupling agent to modify the resin matrix can increase the bonding on the fiber surface. When the addition amount exceeds 3%, the excessive cross-linking between the resin molecules leads to the decrease of the interlayer shear performance of the composite. This paper provided a theoretical basis for improving the infiltration performance and interface strength of aramid composites, and has reference value for the design and manufacture of aramid composites in aerospace and power systems.