Preparation of ultrafine encapsulated pigment dispersion by free-radical sediment polymerization

Polymer encapsulating method was adopted for the surface modification of organic pigment with the purposes of improving the lightfastness and weather fastness of the pigment,enhancing its compatibility with the substrate,and broadening the application field of the pigment.In this study,ultrafine C.I.Pigment Yellow 13 /poly-styrene-maleic acid(P.Y.13 /PSMA composite) dispersion was prepared by free-radical precipitation polymerization.The effects of PSMA structure on the property of the encapsulated pigment were investigated.Experimental results revealed that the weight ratio of feeding monomers to pigment(WC/P),the molar ratio of feeding maleic acid to styrene(Mm/s) and the weight ratio of feeding initiator to monomer(Wi/c) in aqueous medium had significant influences on particle size and contact angle of the P.Y.13 /PSMA composite dispersion.The optimal P.Y.13 /PSMA composite dispersion was achieved when using WC/P at 24%,Mm/s at 1.0 and Wi/c at 0.8%.Fourier transform infrared(FTIR) spectra and transmission electron microscopy(TEM) demonstrated that P.Y.13 was successfully encapsulated with PSMA.