Synthesis and characterization of pH-sensitive block polymer poly (propylene carbonate)-b-poly (acrylic acid) for sustained chlorpyrifos release

A novel pH-sensitive block polymer poly (propylene carbonate)-b-poly (acrylic acid) (PPC-b-PAA) was successfully synthesized by the free radical polymerization and hydrolysis reaction. The polymer structure was characterized with 1H MNR and 13 C NMR. pH-Responsive property and the critical micelle concentration of PPC-b-PPA were studied in detail. The size of nanoparticles at different pH were demonstrated by dynamic light scattering, which the size expanded dramatically with an increase alkaline concentration at 2.5-7.5. Chlorpyrifos (CHP) loaded PPC-b-PAA nanoparticles were synthesized by diffusion dialysis method. PPC-b-PAA nanoparticles has high drug loading efficiency and drug loading content, good stability. With the increasing of acrylic acid dosage, the CHP release rate was decreased in PBS. PPC-b-PAA nanoparticles has special effect for drug release.