Abstract
Microencapsulated n-octadecane with melamine-formaldehyde resin (MF) as shell was successfully fabricated by in-situ polymerization. Three kinds of emulsifiers, sodium dodecyl sulfate (SDS), styrene-maleic anhydride copolymer (TA) and sodium dodecylbenzene sulfonate (DBS) were used in the emulsification. The effects of pH values of the emulsion on morphology of microcapsules were investigated. In addition, the effects of diameters ranging from 5 to 200 µm of n-octadecane emulsion droplets and the microcapsules on crystallizing behavior were studied using Optical Microscope (OM) and Differential Scanning Calorimeter (DSC), respectively. The results indicated that the optimum microcapsules were synthesized with SDS under pH 3.0. The crystallization rates of liquid n-octadecane emulsion droplets and the microcapsules lowered with reducing its size regularly.
ACKNOWLEDGMENTS
The authors are thankful to the National Natural Science Foundation of China (No. 50573058) and Specialized Research Foundation for the Doctoral Program of Higher Education (No. 20050058004) for the financial support.
Notes
ΔH-average enthalpy of |ΔHm| and |ΔHc|; Measured PCM content-ratio of ΔH of MicroPCMs and that of corresponding n-octadecane bulk.