Diblack-copolymers of polyacrylamide (PAA) and monomethyl ethers of poly(ethylene glycol) (MEPEG) of different molecular weights (M(v) (MEPEG) = 7.5.10(2)-5.10(3)) are obtained. The positive matrix effect depending on the length of MEPEG chains is revealed. The copolymerization kinetics is measured by dilatometry and compared with that of AA homopolymerization. Molecular parameters of synthesized copolymers are determined by size exclusion chromatography (SEC). Structural investigations are carried out by differential scanning calorimetry (DSC).