Solventless preparation of ammonium persulfate microcapsules with a polypyrrole shell.

Microencapsulating water-soluble ammonium persulfate (APS) cores as gel breakers were of considerable significance for improving the gel breaking efficiency of fracturing fluids in oil fields. The general approach, which was used for synthesizing microcapsules containing water-soluble APS cores, oil-soluble organic solvents as the continuous phase, was usually essential to retain the water-soluble properties of the core materials. From the environmentally friendly view, solventless methods for synthesizing these microcapsules will be more desirable and attractive. Presented in this report is a novel solventless method to fabricate the relevant microcapsules, water-soluble APS as the cores and polypyrrole doped with petroleum resin as the shells. The release pattern of the microcapsules is burst release, and its beginning release time could be precisely controlled by changing the type of doped resins and temperatures, which makes them promising candidates for oil exploration, monomer polymerization, fiber printing, batteries, and grease applications. [ABSTRACT FROM AUTHOR]