十二酸/十六酸/十四酸三元复合相变体系研究

采用步冷曲线法测定了不同比例的十二酸(LA)/十六酸(PA)二元体系的相变温度,绘制了该体系的T-X相图。在其最低共熔点处引入十四酸(MA)组成三元体系,测定了该三元体系不同组成的相变温度,绘制其T-X相图。采用差式扫描量热仪(DSC)和红外光谱(FT-IR)对三元体系中最低共熔物的热性能和稳定性能进行表征。结果表明:LA/PA质量比为76∶24时形成最低共熔物,其最低共熔温度为31.7℃,相变焓为272.9J/g;LA/PA/MA三元体系在质量比为60.8∶19.2∶20时能形成低共熔物,其低共熔温度为26.9℃,相变焓为264.2J/g,连续相变过程无分层现象,300次热循环后热稳定性好。

Study on the ternary phase change system of LA/PA/MA

The T-X phase diagram and phase change temperature of Lauric acid(LA) and Palmitic acid(PA) with different proportions were detected by cooling curve method.The ternary system was formed by introducing myristic acid(MA) nearby the lowest eutectic point.With the same method the phase change temperatures and T-X phase diagram of the ternary system of LA/PA/MA were determined.The thermal properties and stability performance of the composite phase change material(PCM) were investigated by differential scanning calorimetry(DSC) and Fourier transform infrared(FT-IR) techniques.Experimental results showed that the binary eutectic mixture was formed when the mass ratio of LA/PA was 76:24,and its phase change temperature and latent heat were 31.7 ℃ and 272.9 J/g,respectively.The ternary eutectic system of LA/PA/MA can be earned when the mass ratio of LA/PA/MA was 60.8:19.2:20,and its phase change temperature and latent heat were proved as 26.9 ℃ and 264.2 J/g,respectively.No stratification has been observed during the continuous phase process of the ternary system.The good thermal stability of the ternary system after 300 thermal cycles was proved by the FT-IR.