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

Samples of phase-change materials (PCM) microcapsules containing solidparaffin or camel fat as core materials were synthesized by in situ polymerizationusing melamine-formaldehyde as shell material. The microcapsuleswere made in two consecutive steps, emulsification of PCMs in water and the,encapsulation. Differential scanning calorimetry (DSC), Fourier transform infra-red(FTIR) spectroscopy, optical and scanning electron microscopy (SEM) and particle sizeanalysis were used to characterize the microcapsules. A simple test method wasdevised to visually examine the oil seepage and leaking from microcapsules. Forparaffin microcapsules the effect of agitation speed, through a limited range, wasexamined on the size of microcapsules during the formation of pre-polymer. Themicrocapsules were prepared from camel fat by the similar procedure used for theparaffin microcapsules. The microcapsules were spherical in shape with harsh surfacesas 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 resinwas strong and stable enough to prevent the liquid oils from seepage and leaching at80°C. The effect of prepared camel fat microcapsules on the delay of heat wasdetermined through examining a covered polyester/viscose-fibre fabric. The loadedfabric samples with 10% (w/w) camel fat microcapsules delayed the rise of temperatureof the covered thermometer when exposed to heat at 50°C oven. Newton''s law of cooling was applied to determine the delay in temperature change.