凝胶化条件对定型相变材料热性能的影响  

Influence of Gelatinization Conditions on Thermal Properties of Shape-Stabilized Phase Change Materials for Thermal Energy Storage

作　　者：何丽红[1] 李菁若[2] 朱洪洲[1] 卢章天 

机构地区：[1]重庆交通大学交通土建工程材料国家地方联合工程实验室,重庆400074 [2]招商局重庆交通科研设计院有限公司,重庆400067

出　　处：《高分子材料科学与工程》2015年第3期59-64,共6页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(51178491);交通运输部科技项目(2012-319-814-200)

摘　　要：根据溶胶凝胶化原理,从热力学不稳定与反离子聚沉角度出发,分别采用温度促凝法与反离子促凝法制备了PEG(聚乙二醇)/SiO2(二氧化硅)定型相变材料(SS-PCMs)。运用差示扫描量热、X射线衍射与红外光谱分析对比研究了凝胶化条件对SS-PCMs相变焓与相变峰温的影响。结果表明,温度促凝法制备的PEG/SiO2SS-PCMs相变焓为36.1~128.4J/g,较相同质量比例的纯PEG低,相变峰温也稍有降低;PEG/SiO2SS-PCMs中PEG与SiO2仅为物理作用,PEG相变行为主要受SiO2内外界面的牵制作用与微孔结构的空间位阻作用的影响。反离子促凝法制备的Ca-PEG/SiO2SS-PCMs相变焓为32.6~91.5 J/g,相变焓损失率高,但相变峰温较纯PEG有所升高;Ca-PEG/SiO2SS-PCMs中,PEG相变行为除了受限于SiO2的物理作用,PEG中C-O-C键的氧亦给出孤对电子与Ca2+形成配位键,改变PEG分子构象与结晶结构,导致相变焓损失严重。即凝胶化条件决定了SS-PCMs组分间相互作用方式,从而影响着PEG/SiO2定型相变材料的热性能。经对比分析,温度促凝法较反离子(CaCl2)促凝法更适合制备PEG/SiO2SS-PCMs。According to gelatinization principle,PEG / SiO2 shape-stabilized phase change materials(SS-PCMs) were prepared by temperature-assisted sol-gel method and countra-ion coagulant-assisted sol-gel method in thermodynamic instability and countra-ion coagulation.The influences of gelatinization conditions on phase change enthalpies and temperature of SS-PCMs were studied by DSC,XRD and FT-IR.The results show that enthalpies of PEG / SiO2 SS-PCMs prepared by temperature-assisted sol-gel method are 36.1 ~ 128.4J / g,which are lower than that of pure PEG with the same mass fraction; and phase change temperatures are slightly lower.For PEG / SiO2SS-PCMs,the interaction between PEG and SiO2 is physical mechanism.The phase transition behavior of PEG is mainly reflected in drag effect of inside and outside interfaces of SiO2 and steric effect of SiO2 mesoporous structure.Enthalpies of Ca-PEG / SiO2 SS-PCMs prepared by countra-ion coagulant-assisted sol-gel method are 32.6 ~ 91.5J / g,the corresponding enthalpy loss rate is high and phase change temperatures are increased.For Ca-PEG / SiO2 SS-PCMs,the enthalpies are severely damaged because the molecular conformation and crystallization structure of PEG are changed due to formation of the coordinate bond between O of PEG C- O- C and Ca2 +.Of course those enthalpies are also affected by the physical action of SiO2.That is,the gelatinization conditions determine the interaction mechanism among components of SS-PCMs and influence the thermal properties of PEG / SiO2 SS-PCMs.The analysis results show that temperature-assisted sol-gel method is more appropriate method to prepare PEG / SiO2 SS-PCMs than countra-ion(CaCl2) coagulant-assisted sol-gel method.

关 键 词：聚乙二醇 温度促凝法 反离子促凝法 定型相变材料 热性能 

分 类 号：TB34[一般工业技术—材料科学与工程]