Effects of Stirring Rates and Dodecyl Mercaptan on Nanocapsules containing n-octadecane Prepared by miniemulsion polymerization

摘要

Nano-encapsulated n-octadecane (NanoPCMs) was synthesized by miniemulsion polymerization using styrene-divinybenzene co-polymer as shell and n-octadecane as core. The surface morphology, phase change properties, thermal stability and diameter distribution were investigated using Scanning Electronic Microscopy (SEM), Transmission Electron Microscope (TEM), Differential Scanning Calorimetry (DSC),Thermogravimetric Analyzer (TG) and laser particle size analysis, respectively. The experimental results show that, the stirring rate of 6000 rpm is suitable for the nano-encapsulation. Dodecyl mercaptan (DDM) has great influence on the morphology of NanoPCMs. When DDM was employed in miniemulsion polymerization, the fabricated nanocapsules are almost spherical and their surfaces are smooth. The enthalpy of the nanocapsules is 84 J.g-1, which corresponds to 37 wt% n-octadecane. The super-cooling was not observed in the DSC cooling curve. The thermal resistant temperature of NanoPCMs is about 226oC.