A thickening copolymer and a non-continuous method for preparing the same. The preparation method first involves a polymerization reaction between a dihalogenated compound and a polyhydroxylated monomer, followed by a reaction with a hydrophobic monoalcohol. The copolymer is used in a rheology control composition and a method of controlling the viscosity of an aqueous composition, such as an ink, a varnish, an adhesive, and a paint.