Study On Preparation And Properties Of Microcapsulation Of Reversible Thermochromic Cobaltous Chloride/ Polyethylene- Ethyl Cellulose(CC/PE-EC)

Reversible thermochromic materials are high performance in industry, national defence and daily life etc. Nowadays, an increasing number of attentions have been paid to the microcapsule-type reversible thermochromic materials because of its high performance of reversibility, stability and compatibility. Microcapsule technology and its development were introduced in this paper. Microcapsule with water-soluble materials preparation was solved in this paper. The background, meaning and the way of my study were pointed out.In this paper, using ethyl cellulose (EC), polyethylene (PE), cyclohexane (HC) and Span80 to prepare PE/EC thermochromic microcapsule by oil phase separation method. The wall of microcapsule is made of ethyl cellulose and polyethylene, whereas the core is made of thermochromatic material (CoCl₂·6H₂O). HC and Span80 are used as solvent and emulsifier, respectively. The effects of the processing parameters, including the mass ratio of core material to shell material, the rate of stiring, the time of phase separation, shell material content, stabilizer content, solvent content and emulsifier concentration were mainly discussed. Mechanism of preparing PE/EC thermochromic microcapsule by oil phase separation method was analysed in this paper. The physical properties of microcapsules were investigated using scanning electron microscopy (SEM), optical photographic microscopy (OM), differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and HS-POM. And the heat resistance, solvent resistance, chemical stability and polymer compatibility of the thermochromic microencapsules were investigated. At last, the effects on thermochromism and project performance of the coating and paint in different content of the thermochromic microcapsule were discussed.The results presented here offer an outstanding CC/PE-EC thermochromic microencapsule and show that the reversible thermochromism, environment adaptability and polymer compatibility of the thermochromic microencapsule were improved by microencapsulation. The temperature of color changing of the microencapsule is 41℃, while the time of color changing, the time of color fading of the thermochromic microencapsule were 39s, 48s respectively. And the mean size of microcapsules is 4.5μm. So, the CC/PE-EC microcapsule has possessed a promising applications.