Preparation of Phase-change Material Microcapsules with Paraffin or Camel Fat Cores: Application to Fabrics

摘要

Samples of phase-change materials (PCM) microcapsules containing solid paraffin or camel fat as core materials were synthesized by in situ polymerization using melamine-formaldehyde as shell material. The microcapsules were made in two consecutive steps, emulsification of PCMs in water and then, encapsulation. Differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) spectroscopy, optical and scanning electron microscopy (SEM) and particle size analysis were used to characterize the microcapsules. A simple test method was devised to visually examine the oil seepage and leaking from microcapsules. For paraffin microcapsules the effect of agitation speed, through a limited range, was examined on the size of microcapsules during the formation of pre-polymer. The microcapsules were prepared from camel fat by the similar procedure used for the paraffin microcapsules. The microcapsules were spherical in shape with harsh surfaces as observed by SEM. The average diameter of camel fat microcapsules with 95% confidence limits is 1515±199 nm and that of paraffin is 1600±341 nm. The shell resin was strong and stable enough to prevent the liquid oils from seepage and leaching at 80℃. The effect of prepared camel fat microcapsules on the delay of heat was determined through examining a covered polyester/viscose-fibre fabric. The loaded fabric samples with 10% (w/w) camel fat microcapsules delayed the rise of temperature of the covered thermometer when exposed to heat at 50℃ oven. Newton's law of cooling was applied to determine the delay in temperature change.