Preparation of polyurethane nanocapsules by miniemulsion polyaddition.
The encapsulation of organic liquids in polyurethane nanocapsules by interfacial miniemulsion polycondensation of isophorone diisocyanate and propanetriol has been performed. The influence of type and amount of encapsulated organic liquid has been studied and it was found that the encapsulation efficiency is dependent on the water solubility of the organic liquids, their interfacial tension against water and their compatibility with polyurethane. It was also shown how different types of surfactants and variations in pH and ionic strength of the continuous phase affected the stability during polymerization and the diameter of the miniemulsion droplets and the resulting nanocapsules. The long-chained anionic surfactant Disponil FES77 can be utilized over a larger pH range than SDS due to the contribution of steric stabilization. Relatively narrow size distributions were obtained.
Johnsen
Heidi
H
Department of Synthesis and Properties, SINTEF Materials and Chemistry, Trondheim, Norway. heidi.johnsen@sintef.no
Schmid
Ruth B
RB
D004655:Emulsions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017953:Isocyanates / Q000737:chemistry; D053769:Nanocapsules / Q000737:chemistry*; D009994:Osmolar Concentration; D010316:Particle Size; D011140:Polyurethanes / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry
D004655:Emulsions; D017953:Isocyanates; D053769:Nanocapsules; D011140:Polyurethanes; D013501:Surface-Active Agents; C015301:isophorone diisocyanate