Preparation and properties of polymer-encapsulated phthalocyanine blue pigment via emulsion polymerization

Polymer-encapsulated phthalocyanine blue pigment dispersion was prepared with a polymerizable dispersant by emulsion polymerization method, and the effect of preparation conditions on the particle size of dispersion was investigated. Dynamic light scattering measurement demonstrated that allyloxy nonyl-phenoxypropanolpolyoxyethyleneetherammonium sulfonate (ANPS) was suitable for phthalocyanine blue pigment modification. The polymer-encapsulated phthalocyanine blue pigment dispersion with the small particles was obtained when the mass ratio of ANPS to phthalocyanine blue pigment, styrene (St) to phthalocyanine blue pigment, and ammonium persulfate (APS) to St was about 0.2, 0.2, and 0.01, respectively. Transmission electron microscopy (TEM), Fourier transforms infrared spectra (FTIR) and thermogravimetric analyses (TGA) provided supporting evidences for the encapsulation of phthalocyanine blue pigment with the formed copolymer. The polymer-encapsulated phthalocyanine blue pigment dispersion showed excellent stabilities to freeze–thaw treatment and centrifugal force.

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► Polymer-encapsulated phthalocyanine blue pigment was prepared using mini-emulsion polymerization with the polymerizable dispersant.
► Styrene and APS were the optimal co-monomer and initiator for phthalocyanine blue pigment encapsulation.
► The thickness of the layer increased with an increase of amount of styrene.
► The stability of phthalocyanine blue pigment dispersion was greatly improved after encapsulation.