Abstract: This paper selected two crystal forms of titanium dioxide (TiO2) to modify polyamide (PA) fibers, and tested the structure and properties of the two TiO2-modified PA fibers at different addition levels. The results indicate that both anatase TiO2 and rutile TiO2 can improve the delustrant properties of PA fibers, with the latter achieving superior delustrant performance; the diffuse reflectance of UV light increased by 8.1% – 12.8% and absorbance increased by 0.07 – 0.13 compared with unmodified fibers. However, both forms lead to a decline in the mechanical properties of PA fibers, with anatase TiO2 having a greater effect on breaking strength. Based on a comprehensive evaluation, when rutile TiO2 is added at 0.6%, the modified PA fiber exhibits a breaking strength of 1.89 cN/dtex, a UV light diffuse reflectance improvement of 8.1%, and an absorbance increase of 0.07, demonstrating relatively optimal overall performance.

Key words: titanium dioxide; modification; polyamide fiber; melt spinning; rutile; anatase