“…In addition to the N -halamines that could be bonded to the fibrous substrates directly, many other substrates and N -halamines are not able to react with each other, a medium which serves as a bridge between N -halamines and fibrous materials is often required. Crosslinking agents, like 1,2,3,4-butanetetracarboxylic acid (BTCA) [ [91] , [92] , [93] , [94] , [95] , [96] , [97] ], dimethylol-5,5-dimethylhydantoin (DMDMH) [ 71 , 98 , 99 ], and citric acid [ 100 ], have been widely applied to react with N -halamines and fibers for the fabrication of NFMs due to their excellent chemical reactivity. For example, Li et al [ 101 ] attached N -halamine precursor compound, 2,2,6,6-tetramethyl piperidinol (TMP), onto cotton fabrics using BTCA as a crosslinker.…”