十六醇/十六酸/十二酸三元复合相变体系研究

Study on the Ternary Phase Change System of H/PA/LA

采用步冷曲线法测定了不同质量比的十六醇(H)/十六酸(PA)二元体系的相变温度,绘制了该体系的t-x相图;在其最低共熔点附近引入十二酸(LA)组成三元体系,同样测定了该三元体系在不同质量比下的相变温度,得到了其t-x相图.采用差示扫描量热仪(DSC)和傅里叶变换红外光谱(FTIR)对上述二元和三元体系中低共熔物的热性能和稳定性进行表征.结果表明:不同质量比的H-PA二元体系均能形成共熔物,H与PA的质量比分别为6∶4和7∶3时引入LA的三元体系能形成最低共熔物;H,PA,LA这三者的质量分数之比分别为30∶20∶50和35∶15∶50的三元体系,其相变焓和相变温度分别为179.63,177.87J/g及26.5,27.0℃,连续相变过程无分层现象,1 200次热循环后热稳定性好.

The t-x phase diagram and phase change temperature of hexadeeanol（H） and palmitic acid（PA） with different proportions were determined by cooling curve method. The ternary system was formed by introducing lauric acid（LA） at near lowest eutectic point. With the same method the phase change temper- atures and t-x phase diagram of the ternary system of H/PA/LA were determined. The thermal properties and stability performance of the composite phase change material were investigated by differential scanning calorimetry（DSC） and fourier transform infrared spectroscopic（FTIR） techniques. Experimental results show that the binary eutectic mixture is formed at the different ratio of H to PA. The ternary eutectic sys- tems can be formed by introducing LA in the binary system of H/PA when the mass ratios of H to PA are 6：4 and 7： 3. At a mass proportion of 30 ： 20 ： 50 and 35 ： 15： 50（H/PA/LA）, the latent heat and the lowest eutectic point are 179.63 J/g and 177.87 J/g, 26.5 ℃ and 27.0 ℃, respectively. During the contin- uous phase change process of the ternary system no stratification was observed. The good thermal stability of the ternary system was proved by the FTIR and DSC after 1 200 thermal cycles.