Abstract: The paper introduces the method of making compound yarn with pure carbon fiber filament bundles and the process method of blending glass fiber and carbon fiber filaments to produce specialty yarns. The former method can achieve almost similar stress between the inner and outer fibers in the compound yarn, the strength utilization rate of the fiber is greatly improved compared with other twisting processes, and the elasticity of the carbon fiber filament compound yarn is increased. Meanwhile,the fibers in the compound yarn are not tightly entangled, which can meet the requirements of resin penetration in the later process. The latter method can change the synthetic strength distribution of glass fiber/carbon fiber blended yarn by separately adjusting the content of carbon fiber, and greatly improve the fatigue resistance of glass fiber. In addition, the application of specialty twisting technology in the blending of aramid fiber and PTFE fiber is also studied in the pa per.

Key words: high-performance fibers; tensile modulus; carbon fibers; compound yarn; twisting