二元脂肪酸/生物基SiO_2复合相变材料的制备与性能

Preparation and properties of binary fatty acids/bio-based SiO_2 phase change composites

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。

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 SiO_2（b-SiO_2）powder extracted from waste straw and straw ash was the carrier.Then LA-PA/b-SiO_2 amorphous phase change energy storage materials were prepared by melt impregnation method.The structure and properties of LA-PA/b-SiO_2 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-SiO_2.LA-PA is bound to the b-SiO_2 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-SiO_2 phase change composite decreases with the increase of b-SiO_2 content.The DSC and TGA analysis show that the LA-PA/b-SiO_2 phase change composites have good properties of phase transformation and thermal stability.The enthalpy of phase change is between 67.36-146.0J/g.