Influence of the Composition of Block Copolymers of Poly-2-alkyl-5,6-dihydroxazines on Their Behavior in Solutions

Block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine and poly-2-methyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine. Using NMR spectroscopy, it was determined that in copolymers the component fraction varies in a tenfold range. The hydrodynamic characteristics of the synthesized copolymers were determined using molecular hydrodynamics and optics methods and it was shown that they are flexible-chain polymers with an equilibrium rigidity of about 2 nm. The behavior of block copolymers in water-salt solutions depends on the content of blocks: an increase in the fraction of the more hydrophobic poly-2-isopropyl-5,6-dihydrooxazine leads to a decrease in the phase separation temperature and LCST. The addition of NaCl leads to a slight decrease in the phase separation temperature.