二元脂肪酸/生物基SiO_2复合相变材料的制备与性能

为了获得适用于建筑领域的相变材料和相变温度,选用月桂酸(LA)和棕榈酸(PA)共混制备的二元低共熔脂肪酸(LA-PA)作为储能材料,废弃稻草和稻草灰提取的生物基SiO_2(b-SiO_2)粉末作为载体,采用熔融浸渗法制备了LA-PA/b-SiO_2定形相变储能材料。采用FTIR、XRD、比表面测试、SEM、DSC、TGA对LA-PA/b-SiO_2复合相变材料的结构与性能进行分析。结果表明:LA-PA和b-SiO_2并不是简单的物理相互作用;LA-PA被束缚在b-SiO_2多孔网络中,从而在固相变为液相时,相变材料不会泄露。通过XRD分析可得,随着b-SiO_2含量的增加,LA-PA/b-SiO_2复合相变材料的结晶度降低。由DSC和TGA分析可知,LA-PA/b-SiO_2复合相变材料具有良好的相变性质和热稳定性,相变焓在67.36~146.0J/g之间。

Preparation and properties of binary fatty acids/bio-based SiO2 phase change composites

In order to obtain suitable phase change materials and phase transition temperature in the file of construction, lauric acid (LA)and palmitic acid (PA) were blended to prepare binary eutectic fatty acids (LA-PA) as energy storage material, bio-based SiO₂ (b-SiO₂)powder extracted from waste straw and straw ash was the carrier. Then LA-PA/b-SiO₂ amorphous phase change energy storage materials were prepared by melt impregnation method. The structure and properties of LA-PA/b-SiO₂ phase change composites were analyzed by FTIR, XRD, specific surface area analysis, SEM, DSC and TGA. The results show that there is not a simple physical interaction between the LA-PA and the b-SiO₂. LA-PA is bound to the b-SiO₂ porous network, thus the phase change materials will not leak when the solid phase is changed into a liquid phase. XRD analysis shows that the crystallinity of the LA-PA/b-SiO₂ phase change composite decreases with the increase of b-SiO₂ content. The DSC and TGA analysis show that the LA-PA/b-SiO₂ phase change composites have good properties of phase transformation and thermal stability. The enthalpy of phase change is between 67.36-146.0 J/g.