十八醇/DMDBS凝胶态相变材料的制备与性能研究

摘要

A 1-octadecanol (OD) / 1,3 ∶ 2,4-di-(3,4-dimethyl) benzylidene sorbitol (DMDBS) composite was prepared as a novel form-stable phase change material (PCM),and the properties of the composites such as the gel-to-sol transition temperature,the latent heat and the thermal storage performance were characterized.The composite was prepared by impregnating DMDBS into OD and the maximum feasible weight percentage of OD was determined to be 94.2wt％.The gel-to-sol transition temperature of the composite PCM was 177.4-189.8℃,which is well above the melting point of 1-octadecanol.Differential scanning calorimeter (DSC) was used to determine the melting and freezing enthalpies of 1-octadecanol in the composite PCM and the values are 184.4 and 180.9J/g,respectively.After 100 thermal cycles,the phase change temperature changed little,and the enthalpies reduced slightly.The microstructure of the composite PCM and xerogel were observed by SEM.The relationship between the amount of DMDBS additive and the leakage was also discussed.The thermal conductivity of the composite PCM was improved by doping with exfoliated graphite.%研究了凝胶因子在醇类复合相变材料中的应用,以十八醇为储能材料,以二(3,4-二甲基苄叉)山梨醇(DMDBS)为凝胶因子制备了一种新的凝胶态复合相变材料,得到的复合相变材料具有较高的储能密度,相变材料的含量可达到94.2％.所制备的复合相变材料不易发生泄漏,DMDBS添加量为3％时,复合相变材料的凝胶解缔温度为177.4～189.8℃,远高于十八醇的熔点.DSC结果表明,复合相变材料的熔融焓变和凝固焓变分别为184.4和180.9J/g.经过100次热循环实验后,复合相变材料的相变温度没有明显变化,焓变值略有降低.通过SEM观察了复合相变材料和干凝胶的表面形态.通过添加膨胀石墨(EG)提高了复合PCM的导热性,使升温和降温时间分别缩短了54.75％和56.36％.