Encapsulation of nano Disperse Red 60 via modified miniemulsion polymerization. I. Preparation and characterization

Nanocolorant, nano Disperse Red 60, was successfully prepared via modified miniemulsion polymerization process. Transmission electron microscopy was employed to determine the droplet and particle sizes. The effects of the speed and the time of homogenization, the surfactant nature and its amount, the presence of dye, the initiator nature, and the presence of a crosslinker on the morphology and particle size of nanocolorant were studied. UVvis absorption spectra of nanocolorant with respect to the commercial corresponding dye showed a hypsochromic shift confirming the decrease in particle size. Fourier transform infrared spectra proved the chemical composition of nanocolorant particles assisting the incorporation of the dye within the polystyrene particles. The monomer conversion, surface tension, and apparent sedimentation stability also were measured. The relative electrical conductivity of the suspension was used for determining the polymerization mechanism. The kinetic polymerization was investigated using a pseudofirst-order and it is found that the rate constant of polymerization equals 0.01358 min-1. Zeta potential measurements were employed for miniemulsion which showed that it has good stability at all range of pH. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012