Synthesis and characterization of thermosensitive and pH-sensitive block copolymers based on polyetheramine and pullulan with different length

Novel thermo- and pH-sensitive block copolymers were prepared via reductive amination by end-to-end coupling reaction between the aldehyde function (reducing sugar) of pullulan with varied molar masses and the amine function of polyetheramine (i.e. methoxypoly (oxyethylene/oxypropylene)-2-propylamine) or PEO-PPO amine. The conditions of synthesis, followed by FTIR and 1H NMR are well-controlled and depend strongly on pullulan length. The properties of copolymers in aqueous solution were investigated by SEC/MALS/DRI and absorbance measurements as function of temperature and pH, providing evidence of thermo- and pH-sensitive self-assembly of the copolymers.