摘要
无机水合盐相变储能材料较低的导热系数导致了其缓慢的吸放热速率,限制了水合盐的实际应用。本工作以芒硝(Na_(2)SO_(4)·10H_(2)O)为相变材料、聚丙烯酸钠(PSA)为支撑材料,利用硼砂改善相变体系的过冷度,借助高导热的碳纳米纤维(CNFs)来提升复合相变材料的导热系数。从SEM图中可知,CNFs-Na_(2)SO_(4)·10H_(2)O/PSA被成功制备,且芒硝和功能化的CNFs嵌入到PSA形成的三维网络结构中。拉曼光谱和红外光谱的结果表明相变体系各组分之间具有良好的化学相容性。DSC曲线表明,聚丙烯酸钠与芒硝之间的相互作用使得体系相变行为得到调整,Na_(2)SO_(4)·10H_(2)O/PSA的熔融焓和结晶焓分别为197.2 J/g和137.0 J/g。与Na_(2)SO_(4)·10H_(2)O/PSA相比,CNFs-Na_(2)SO_(4)·10H_(2)O/PSA的导热系数得到显著提升,固态热导率达到1.2 W/(m·K)左右,液态热导率达到1.0 W/(m·K)左右。此外,经过300次的循环试验,复合相变材料的熔融焓和结晶焓分别下降了23.3%、28.8%。
The low thermal conductivity is a hindrance to salt hydrate as it leads to slow rates of heat absorption and release,which limits the practical application of inorganic hydrate salts.In this work,a series of Na_(2)SO_(4)·10H_(2)O/PSA composite materials with different weight ratios were fabricated by using the Na_(2)SO_(4)·10H_(2)O as phase change materials and polyacrylic acid sodium as a supporting materials,and by adding carbon nanofibers to enhance thermal conductivity.Scanning electron microscopy micrographs revealed that composite PCMs have been successfully prepared,and Na_(2)SO_(4)·10H_(2)O and functionalized carbon nanofibers are embedded in 3D networks of PSA,the above three materials bonding together to form a smooth network structure.FTIR and Raman spectra results indicated that there were no chemical interactions between components in phase transition system.Differential scanning calorimetry suggested that phase transition behavior of the system was adjusted by the interaction between polyacrylic acid sodium and Na_(2)SO_(4)·10H_(2)O,as melting and crystallization enthalpy are 197.2 J/g and 137.0 J/g,respectively.Compared with Na_(2)SO_(4)·10H_(2)O/PSA,thermal conductivity of CNFs-Na_(2)SO_(4)·10H_(2)O/PSA significantly increased,of which thermal conductivity of solid state reached about 1.2 W/(m·K)and thermal conductivity of liquid state was about 1.0 W/(m·K).Moreover,after 300 thermal cycles,melting and crystallization enthalpy of composite phase change materials decreased by 23.3%and 28.8%respectively.
作者
魏宁
铁生年
WEI Ning;TIE Shengnian(College of Chemical Engineering,Qinghai University,Xining 810016,China;New Energy(Photovoltaic)Industry Research Center,Qinghai University,Xining 810016,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第6期16-22,共7页
Materials Reports
基金
青海省自然基金项目(2020-ZJ-909)
材料复合新技术国家重点实验室(武汉理工大学)开放基金项目(2020-KF-1)。
关键词
芒硝
相变材料
碳纳米纤维
功能化
相变行为
导热系数
Na_(2)SO_(4)·10H_(2)O
phase change materials
carbon nanofibers
functional
phase transition behaviors
thermal conductivity
