Preparation Of Capsulated Dodecanol Phase-change Materials By Suspension Polymerization And Orifice Method

In this paper, dodecanol microencapsulated phase change materials were prepared using dodecanol ?DA? as the core material, polymethyl methacrylate ?PMMA? as wall materiall by suspension polymerization. The influence on dodecanol microcapsules preparation of key factors, including dispersant content, type and content of initiator, core/wall ratio, stirring speed and cross-linking agent content were systematically evaluated. The morphology, chemical structure, phase transition temperature and enthalpy, thermal properties of the dodecanol microcapsules were investigated by scanning electron microscopy ?SEM?, fourier transform infrared spectroscopy ?FT-IR?, differential scanning calorimetry ?DSC?, thermal gravimetric analysis ?TGA? and laser particle diameter analyzer ?PSD?. The results show that the best conditions for preparation of microcapsules were:Sodium salt of styrene-maleic anhydride polymer ?SMA? as dispersant, dispersant content is 7.5%,7.5% 2,2'-azobisisobutyronitrile ?AIBN? as the initiator, the core/shell ratio is 2:1,25% PETRA as crosslinker.The contents of DA in microcapsules nearly 66% and the latent heats of melting was found to be 137.6. Phase transition temperature was 24.33?. Thermal cycling test showed that the microPCMs have good thermal reliability and chemical stability after 500 thermal cyclings. SEM images show spherical microcapsules. The size distribution appears as homogeneous and the particle size intensively ranges from 15.14 ?m to 35.90 ?m. The particles have a mean particle size of 25.65 ?m.Dodecanol macroencapsulated phase change materials were prepared by orifice method. The influence on dodecanol macrocapsules preparation of key factors, including CaCl₂ solution, sodium alginate solution and the addition of dodecanol microcapsules. The optimum conditions for preparation of macrocapsules were:the CaCl₂ concentration is 2%, sodium alginate solution concentration is 1%. According to demand, prepared containing different quality microcapsules, particle size more than 1mm dodecanol macrocapsules. This paper realized the diameter controllable of dodecanol capsules through the selection of method and the other factors in preparation process,which extends the application field of the phase change material.