A series of well-defined polymers with various content of reactive oxirane groups (25–100 mol%) were synthesized via atom transfer radical polymerization (ATRP). The acetal derivatives of methyl α-D-glucopyranoside used as bi-, tri-, and tetrafunctional initiators allowed us to design macromolecules containing a sugar moiety in the center with V- and star-shaped topologies, and a length of each polymethacrylate segment in the range of 30–75 units. Various degrees of oxirane ring opening via aminolysis with mono- and diamines (20–100 %) or azidation (100 %) have demonstrated that the reactivity of pendant epoxide groups incorporated into the polymer was strongly dependent on the nucleophile agent and reaction environment. The complete transformation in the reaction with ethylenediamine and sodium azide yielded amphiphilic copolymers with differential solubility (diamine-functionalized polymers in polar protic solvents, e.g., water, versus azide-functionalized polymers in polar aprotic solvents, e.g., dimethylformamide). A few polymeric forms, that is unimers (0.5–1 nm), micelles (5–30 nm), aggregates (170–290 nm) and superaggregates (> 4,500 nm), were indicated by DLS measurements of water-soluble ethylenediamine derivatives of copolymers. Both the epoxy-functionalized polymers and their modified derivatives are potential materials for biomedical applications.