Ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group and applications of chelating heavy metals

A preparation method of an ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group, wherein:

• the ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group has a chemical formula of C[CH2OCH2CH2OCOCH2CH2N(CSSM)CH2CH2NHCSSM]4, wherein M is Na+, K+ or NH4+;
• and a structural formula of
• the preparation method comprises steps of:
• (1) under nitrogen protection, adding ethylenediamine (EDA) and a first amount of low-carbon alcohol to a reaction vessel with a stirrer, a reflux device and a thermometer, evenly stirring, slowly adding a low-carbon alcohol solution containing ethoxylated pentaerythritol tetraacrylate (EO-PETA) drop by drop, performing a first addition reaction;
• and then removing low-carbon alcohol solvent and excessive ethylenediamine through vacuum distillation, and obtaining a light amber viscous product, which is an intermediate product ethoxylated pentaerythritol tetra((N-(2-aminoethyl))-3-alaninate) hyperbranched polymer;
• (2) slowly adding water, alkaline solution and carbon disulfide drop by drop to the ethoxylated pentaerythritol tetra((N-(2-aminoethyl))-3-alaninate) hyperbranched polymer obtained by the step of (1), performing a second addition reaction, and obtaining an aqueous solution of the ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group;
• and
• (3) adding a second amount of low-carbon alcohol to the aqueous solution of the ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group obtained by the step (3), evenly stirring, precipitating a solid product, filtering and drying the solid product to obtain the ethoxylated pentaerythritol core hyperbranched polymer with dithiocarboxylate as side group and terminal group.