Synthesis and characterization of multi-hollow opaque polymer pigments

A new generation multihollow opaque polymer pigment was synthesized by suspension polymerization of water-in-oil-in-water emulsion method, where methyl methacrylate and ethylene glycol dimethacrylate monomer mixture was used as oil phase. The effects of surfactant and cosurfactant composition in terms of hydrophilic/lipophilic balance on the stability of the water-in-oil emulsion and the size of water droplets were studied. Low droplet sizes and the optimum stability were obtained with Span 80&Tween 80 surfactant mixture at an HLB value of 8. The desired size distribution was obtained at monomer/surfactant/water ratio of 75.5/9.4/15.1 at an ultrasonic mixing power of 80 W lasting for 30 s. The surface morphology and hollow structure of polymer pigments were analyzed by scanning and transmission electron microscopy techniques. L*a*b color and gloss properties of polymer pigments were examined. The opacity values were assessed by contrast ratio measurements, and the pigments provided up to 97.3% opacity with 50% v/v solid content in resin. In addition, the pigments exhibited low gloss values and yielded matte films. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43696.