Maleoyl chitosan oxidized derivative as well as preparation method and application thereof

The invention provides a maleoyl chitosan oxidized derivative as well as a preparation method and application thereof. The preparation method comprises the following steps: adding chitosan into water, stirring, adding sodium carbonate, continuously stirring, adding maleic anhydride, stirring again, and adding 2, 2, 6, 6-tetramethylpiperidine-1-oxygen free radicals for reaction; centrifugally separating a reaction product, and collecting supernate; and adjusting the pH value of the supernate to 3-4, centrifuging and drying. According to the preparation method disclosed by the invention, water is used for replacing toxic acetone as a solvent, and the prepared maleoyl chitosan oxidized derivative is relatively high in substitution degree and has relatively good water solubility under neutral and alkaline conditions; the maleoyl chitosan oxidized derivative can be used for preparing dialyzing paper, a wet strength agent PAE which has potential harm to human bodies and the environment is replaced, and the prepared