Preparation method of salt-resistant hyperbranched polycarboxylate superplasticizer

The invention discloses a preparation method of a salt-tolerant hyperbranched polycarboxylate superplasticizer, which comprises the following steps: carrying out substitution reaction on polyhydric alcohol and unsaturated chloride to obtain a polymerizable active core, carrying out copolymerization reaction on the active core, carboxylic acid small monomers and sodium p-styrenesulfonate to obtain a hyperbranched active end, and carrying out polymerization reaction on the hyperbranched active end to obtain the salt-tolerant hyperbranched polycarboxylate superplasticizer. And carrying out atom transfer radical polymerization (ATRP) reaction with carboxylic acid small monomers under an initiation system consisting of halogen-containing unsaturated monomers and transition metal complexes to obtain the salt-tolerant hyperbranched polycarboxylic acid water reducing agent. Compared with a traditional comb-shaped polycarboxylic acid water reducer, the synthesized salt-resistant hyperbranched polycarboxylic acid water