Facile fabrication of luminescent ultra‐high molecular weight polyethylene fibers based on novel alkyl‐substituted 1,8‐naphthalimide fluorescent dyes

Abstract Ultra‐high molecular weight polyethylene (UHMWPE) fiber, with excellent light resistance, and chemical resistance, is one of the most important high‐performance fibers. However, the high hydrophobicity and crystallinity make it difficult to color, restricting the development of colored fluorescent UHMWPE protection materials. In this study, three hydrophobic fluorescent dyes ( NC4 , NC8 , NC16 ) for fluorescent dyeing of UHMWPE were developed by introducing alkyl substituents of different lengths (butyl, octyl, and hexadecyl) and polar cyano groups onto 4‐NH‐1,8‐naphthalimide fluorescent chromophore. The relationship between the structures and the application performance was studied, and theoretical calculations were combined to explore the influence of the substituents on the spatial and electronic effects of fluorescent dyes. With the extension of the alkyl chain, the dye‐uptake rate and building‐up property was enhanced, and the equilibrium dye‐uptake rates for NC4 , NC8 , and NC16 were 18.21%, 93.22%, and 62.96%, respectively. NC8 , which was proven to have high hydrophobicity and maximum dipole moment, exhibited the highest dye‐uptake rate. The dyed UHMWPE fabrics exhibited strong yellow‐green fluorescence. This study provides a facile strategy for constructing luminescent UHMWPE protection materials.