Synthesis And Characterization Of Block Ionomers And Research On Their Self-assembled Nanocapsutes

With PEG/IPDI/DMPA as the comonomer and DBTDL as the initiator, block ionomerswere prepared in solution by stepwise addition polymerization method. Block ionomers wereobtained after the addition of neutralizer (organic amine). Using block ionomers as shell andthe hydrophobic functional organic molecule DCOIT as core, nanocapsules of DCOIT wereassembled in aqueous phase interface.The structure of block ionomers was characterized by FT-IR,1H-NMR, GPC, particle size,surface tension, DSC and TEM. FT-IR analysis confirmed that block ionomers with desiredpolyurethane structure were synthesized. GPC determination results of molecular weight, withthe increase of the [NCO]/[OH] ratio, the molecular weight of block ionomers showeddecreasing trends. Particle size analysis showed that their particle size distribution was in linewith nano-scale range. DSC proved that the molecular chain of block ionomers was blockcopolymers which were composed of two phased—hard segment and soft segment. Blockionomers showed a relatively regular spherical particle status in water solution under TEM.Solution behavior of block ionomers in water phase was studied by particle size, reducedviscosity, rotational viscosity, conductivity and Cc.c (critical congregating concentration).Particle sizes of all block ionomers were about200nm. Block ionomers were thinner aftershearing, the rotatinonal viscosity was measured at the speed of the rotor40rpm. As PEGmolecular weight increased, Cc.cs of block ionomers decreased.Release behavior of nanocapsules prepared by self-assembly of block ionomers was studiedby UV-visible spectrophotometry method. Study of UV-visible spectrophotometry methodshowed that the nanocapsules have a certain release function.