Preparation method of superabsorbent polymer and superabsorbent polymer prepared thereby

A preparation method of a superabsorbent polymer, the method comprising:

• forming a water-containing gel polymer by performing thermal polymerization or photopolymerization of a monomer composition including water-soluble ethylene-based unsaturated monomers and a polymerization initiator;
• drying the water-containing gel polymer;
• pulverizing the dried polymer;
• surface-crosslinking the pulverized polymer;
• and
• treating the surface-crosslinked polymer with a polycarboxylic acid-based copolymer having repeating units represented by the following Chemical Formula 1-a and Chemical Formula 1-b:
• wherein, in Chemical Formula 1-a and 1-b,
• R1, R2, and R3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,
• RO is an oxyalkylene group having 2 to 4 carbon atoms,
• M1 is hydrogen or a monovalent metal or non-metal ion,
• X is —COO—, an alkyloxy group having 1 to 5 carbon atoms, or an alkyldioxy group having 1 to 5 carbon atoms,
• m is an integer of 1 to 100,
• n is an integer of 1 to 1000, and
• p is an integer of 1 to 150, and provided that there are two or more of p, two or more repeating (—RO—)s are the same as or different from each other.