六羟基化合物为骨架的高分子固-固相变材料的合成与性能

分别使用三种含6个羟基的化合物(山梨醇、双季戊四醇和肌醇)作为分子骨架,聚乙二醇(PEG)作为相变功能链,4,4'-二苯基甲烷二异氰酸酯(MDI)为交联剂,合成了3种具有不同交联结构的新型固-固相变储能材料。通过傅里叶变换红外光谱(FT IR)、X-射线衍射(XRD)、偏光显微镜(POM)、示差扫描量热法(DSC)和热重量分析法(TG)分别对合成材料的分子结构、结晶性能、相变行为和热稳定性进行了研究。结果显示,所制备的材料在30~70℃温度范围内具有典型的固-固相变特性,其升温和冷却过程的相变焓最高可达107.5J/g和102.9J/g。此外,通过热重分析发现所合成材料具有较好的可重复使用性和热稳定性。因此,合成的新型固-固相变材料在热能储存和控温领域具有巨大的应用潜力。     

接枝共聚法制备聚乙二醇(PEG)/聚乙烯醇(PVA)高分子固-固相变材料性能研究

用接枝共聚法将具有相变特征的聚乙二醇(PEG)接枝到具有较高熔点的聚乙烯醇(PVA)主链上,得到了系列性能稳定的PEG/PVA高分子固-固相转变材料,用DSC,WAXD和POM对其相变行为及形态结构进行了研究.结果表明,该材料呈现出可逆的固-固相转变特性;其结晶峰值温度和相变焓比纯PEG低,接枝率对相变温度和归一化相变焓影响不大;接枝率只影响结晶与熔融行为,不影响结晶结构.     

聚乙二醇型聚氨酯软硬段对其相变储热性能的影响

以不同分子量的聚乙二醇(PEG)为软段,MDI-BDO为硬段,采用两步法溶液聚合合成一种具有固-固相变储热性能的聚氨酯材料.通过DSC,WAXD等测试手段对体系的软硬段结晶性,微相分离,相变可逆性及循环热稳定性进行研究,结果表明,聚氨酯中硬段的存在对软段结晶有着很大的影响,当软段分子量达到2000或以上时,软段才具有较大的结晶度和熔融相变焓,且硬段含量必须高于一定值才能形成较为完善的物理交联网络以保证材料在发生相变时维持固体状态.同时符合这两个条件的试样能具有较好的固-固相变储热性能.就软段PEG含量及分子量对材料储热性能的影响进行了研究,通过调节软段含量与分子量得到一系列具有不同相变焓和相变温度的聚氨酯固-固相变储热材料.经测试还发现,该材料具备很好的相变可逆性和循环热稳定性,是一类很有开发前景的相变储热材料.     

KBF4非等温固-固相变热性质的测定

利用DTA-TG和DSC热分析技术研究了无机塑晶材料KBF4固-固相变的热性能,测得转变温度为284.13℃,转变焓为105.73J/g.KBF4固-固相变的机理是随着温度的升高,晶体中离子键部分断裂,晶体逐渐由低对称的正交晶系向高对称立方晶系转变,并在这过程中,同时引入化学键的振动和转动无序,从而吸收大量的相变焓.     

聚乙二醇/二醋酸纤维素相变材料的组成与储能性能间的关系

以刚性的二醋酸纤维素 (CDA)链为骨架 ,接枝上聚乙二醇 (PEG)柔性链段 ,可得到一种具有固固相变性能的网状储能材料 .利用该材料的PEG支链从结晶态到无定形态间的相转变 ,可以实现储能和释能的目的 .具体研究了PEG的百分含量及PEG的分子量对材料储能性能的影响 .研究结果表明 ,通过改变PEG的百分含量与PEG的分子量 ,可以得到不同相变焓和不同相变温度的材料     

纤维素丙酸酯-g-二乙二醇正十六烷基醚固-固相变材料的制备及性能

以二月桂酸二丁基锡(DBTDL)为催化剂,微晶纤维素为骨架材料,二乙二醇正十六烷基醚(E2C16)为相变材料,采用化学接枝法制备了系列纤维素丙酸酯-g-二乙二醇正十六烷基醚(CP-g-E2C16)固-固相变材料.利用傅里叶变换红外光谱(FTIR)、核磁共振氢谱(1H NMR)、差示扫描量热仪(DSC)、热重分析(TG)和X射线衍射(XRD)对CP-g-E2C16相变材料的结构和热性能进行了表征.结果表明,得到了E2C16的取代度和接枝含量分别为0.12~0.37和17.1%~33.4%的CP-g-E2C16固-固相变材料.CP-g-E2C16接枝共聚物的相变温度和相变焓分别为25~34℃和40~62 J/g,符合人的体感舒适温度范围.CP-g-E2C16固-固相变材料的耐热温度高于237℃,与E2C16相比提高21~40℃,有望应用于熔融纺丝法制备纤维素基储热调温纤维领域.     

癸二醇和十二烷二醇及其混合物的液固相变研究

使用差示扫描量热法（DSC）和红外光谱法（IR）对1，10-癸二醇（1，10-C10H22O2，A）与1，12-十二烷二醇（1，12-C12H26O2，B）及其二元混合物系统液固相变进行研究。测定了该二元混合系统的相变温度、相变焓和液固平衡相图。该二元系统存在低共熔混合物，其组成为xB=0．333，低共熔温度为328K。该二元混合系统的IR图谱显示存在氢键缔合现象，长链烷烃中的亚甲基在晶格中是有序规则排列的。该系统具有较低的相变温度和较高的相变焓，是一种潜在的低温储能材料。     

氟氢化钾固-固相变的变温红外光谱测定

氟氢化钾（KHF2）晶体随着温度的升高,在196℃发生可逆的固－固相变,晶型由低对称的西方晶系转变到高对称的立方晶系^[1]。由于氟氢化钾的固－固相变焓高,可应用于热能的贮存^[2],它的高温相可用做高电导率的离子导体^[3]。氟氢化钾的应用强烈依赖于本身的晶体性,因此利用各种光谱、X－射线衍射、热分析等技术手段以及量子化学计算对两种晶相结构的研究已日趋完善^[4,5]。而对于其固－固相变升温过程中的动态测定还未见报道,这是由于一般的实验手段难以对升温过程进行原位跟踪所致。变温红外光变法具有简便、快速、实用等优点,因而成为研究相变的有力工具^[6]。本文采用变温红外光谱技术测定了氟氢化钾在不同温度下的红外光谱,发现当温度升高到固－固相变温度时,氟氢化钾的各个特征吸收峰的位置、强度及峰形均发生较大程度的变化,从而为验证氟氢化钾的固－固相变机理提供了依据。     

丙烯腈-衣康酸共聚物接枝聚乙二醇固-固相变材料的制备及表征

将衣康酸与丙烯腈共聚,构建具有双端羧基活性点的聚合物骨架,以二苯甲烷二异氰酸酯(MDI)为桥基,将聚乙二醇(PEG)接枝到聚合物骨架上,制备了丙烯腈-衣康酸共聚物接枝聚乙二醇(AIPCMs).采用红外光谱、差示扫描量热、X射线衍射、偏光显微镜、热失重及水静态接触角等方法研究了其结构、相变潜热性能、结晶性能、结晶形态、热稳定性及亲水性.结果表明,合成的AIPCMs具有固-固相变特性及优异的热储能性能,相变潜热达到70.5 J/g.化学接枝改变了AIPCMs中PEG的结晶结构及结晶形态.AIPCMs的热稳定性优异,初始分解温度达289℃,并且其亲水性较好,接触角最小可达33.71°.     

[n—CnH2n＋1NH3]2ZnCl4配合物相变研究

采用差示扫描量热法(DSC)和热重法(TG),研究了〔n-C_nH_(2n 1)NH_3〕_2ZnCl_4(n=9～12)配合物的热稳定性和固-固相变。该系列配合物的分解反应活化能和热稳定性基本上不随烷基链长而变化。配合物在280～370K存在固-固相变。相变数目表现出奇偶效应。相变热焓ΔH和熵ΔS随着烷基链长的增加而线性增大。主转变的峰值温度随烷基链的增长而升高,相应的相变被归属为烷基铵链的结构相变。     

钴氰化钠/氯化钠固体溶液微晶体的电化学制备及其特性

钴氰化钠与铁氰化钠结构类似,而其在固/液界面上的电子转移特性却并不显著. 使用扫描电化学显微镜（SECM）构建了fL~pL体积的电化学微体系. 在微体系中溶剂蒸发,电解质则会浓缩结晶. 当电活性物质与支持电解质的晶格参数匹配时,二者可发生共结晶形成固体溶液. 本文采用该方法制得钴氰化钠/氯化钠固体溶液微晶体,结合微加工技术构建了固体电极/固体溶液界面,该钴氰化钠在固体溶液中即有很好的电子转移特性.     

Preparation and Characterization of Al8.31Si1.91Mg3.78O20/Al4.8Si1.2O9.6/Mg2.0Al4.02Si4.98O18 Multiphase Material

A two-step sintering method was used to prepare Al8.31Si1.91Mg3.78O20 (corundum solid solution)/Al4.8Si1.2O9.6 (mullite solid solution)/Mg2.0Al4.02Si4.98O18 (cordierite solid solution) multiphase material, for the purposes of making these three crystal structures have point defects which could help the particles diffuse and transfer at high temperature, accelerate the sintering efficiently and enhance the material strength as well as the bulk density. The impacts of different formulas on the structure and properties of the multiphase material were investigated. With XRD and SEM analyses, for each sample, the crystal structure and microstructure were characterized, the crystalline phase content and cell parameters were determined with Rietveld Quantification software, and the properties were tested. The comparative optimal formula determined was calcinated chamotte of 80wt% and calcinated sludge of 20wt%; and its corresponding bending strength and retention rate of bending strength after a thermal shock were 29.74 MPa and 80.15%, respectively.     

Thermodynamics of ionic solid solutions. A new treatment of existing distribution data

Excess amounts of two isomorphous salts, which differ with respect to only one ion (the exchanging ions), added to water and equilibrated produce an aqueous solution of the two salts and a solid solution of one salt in the other. The ratio of the two salts in the liquid phase is, in general, different from that in the coexisting solid. Data for twenty-nine such systems, including pairs of double salts (alums and picromerites), and pairs of simple salts, at or near 25°C, have been reviewed. By making the plausible assumption that the activity coefficients of the exchanging ions in the liquid phase are equal, it has been possible to derive the activity coefficients of the salts in the solid phase in addition to the thermodynamic equilibrium constants for the distributions. The interpretation of the data is compared with that of an earlier paper which drew different conclusions and was based on what is shown to be an erroneous premise. Solid solutions of alums are found, for the most part, to be ideal or nearly so. Of nine picromerite solid solutions containing sulfate as the only anion, seven pairs deviate positively from ideality, one deviates negatively, and one shows both positive and negative deviations. Three other picromerite pairs involving exchange of sulfate, selenate, and chromate ions, show only negative deviations. For the pairs [(NH₄)₂,K₂]SO₄, (NH₄,K)Cl, Ag(Cl,Br), K(Br,Cl), Rb(Br,Cl), (Rb,K)Br, and (Rb,K)Cl the deviations are positive; those for Pb(Cl,Br)₂ are negative, and those for Ba(ClO₃)₂·H₂O are both positive and negative. Independent supporting evidence for some of the conclusions is presented.     

高稳定性CaO-ZrO2固体碱催化剂的表征和催化性能

用共沉淀法经高温焙烧制备了CaO摩尔分数从10%至50%的CaO-ZrO₂系列催化剂, 将其应用于碳酸丙烯酯和甲醇酯交换合成碳酸二甲酯过程, 并通过XRD, FT-IR, BET, ICP, CO₂-TPD, XPS等表征手段研究了催化剂的物性及其催化性能随组成变化的的规律. 结果表明, 当CaO摩尔分数高于30%时, 表面出现游离的CaO, 虽然具有强碱性和高活性, 但是稳定性差; 而当CaO摩尔分数低于30%时, Ca^2＋进入ZrO₂晶格, CaO与ZrO₂形成连续固溶体, 并且随着CaO含量的增加, 晶格氧的电荷密度增加, 催化剂的碱性增强, 使得CaO-ZrO₂催化剂在碳酸丙烯酯和甲醇酯交换合成碳酸二甲酯过程中获得了高活性和高稳定性.     

Solid phase reactivity of sodium oxosalts of manganese

The observed relationships are presented of the solid phase reactivity of the following salts: NaMnO₄, Na₂MnO₄, Na₃MnO₄, Na₄MnO₄, Na₂MnO₃, Na₂Mn₂O₅, Na₅MnO₄, Na₄Mn₂O₅, NaMnO₂, Na₄MnO₃, Na₂MnO₂ and Na₂Mn₂O₃.     

Differentiation between the Green and Turkish Blue Solid Solutions of Vanadium in a Zircon Lattice Obtained by the Sol-Gel Process

In this communication, zircon containing vanadium samples which gradually turn greenish have been prepared by controlling the composition (fluoride addition) and the method of preparation (sol-gel, ceramic and solid impregnation) in order to investigate how to affect the shape and size of the vanadium particles, and their location, clustering and distribution. The level of green color, and consequently the amount of V5+ in the sample, could be associated with the development of an Si-O-Si network in the zircon lattice, bonding with the highly reactive zirconium precursors.     

固相微萃取的发展近况

固相微萃取（SPME）是一种新型的样品预处理方法，随着对此技术发展的深入理解，新型SPME装置不断得到应用和发展。本文对其原理、装置、应用和发展的现状进行了综述。     

高温固体氧化物燃料电池（SOFC）进展

固体氧化物燃料电池(SOFC) 采用的是全固体的电池结构, 不存在液体电解质带来的腐蚀和流失等问题, 而且具有燃料适应性广等突出优点, 近几年发展非常迅速, 已经展示出作为集中或分散发电新技术的前景。本文较详细地介绍了固体氧化物燃料电池的特点、工作原理和关键电池材料的研制, 并全面阐述了国内外发展现状和发展趋势。     

变温红外确定硫氰化铵固-固相变机理(英文)

硫氰化铵分子晶体在固 固转变时 ,能可逆地吸收大量的热。作者利用变温红外光谱确定了其固 固相变机理。结果表明 ,随着温度升高 ,固 固转变时分子晶体内相邻的氢键断裂 ,晶型由低对称转变为高对称并引入振动和转动无序 ,吸收大量热。     

Inorganic functional materials: optimization of properties by structural and compositional control

A review is given of the strategies used to dope inorganic solids and the consequences for properties such as ionic and electronic conductivity. Doping mechanisms involve either substitution of foreign ions onto lattice sites, creation of vacancies on either cation or anion sites, or population of normally empty interstitial sites by either anions or cations. Mechanisms for charge compensation associated with aliovalent doping are reviewed and examples are given in the fields of solid state ionics and high-temperature superconductivity. The strategies used for targeting materials with new properties are reviewed, including a surprising number of cases where startling new properties are encountered in well-known materials. Specific examples discussed include MgB2 superconductor, Na beta-alumina sodium ion conductor, Ca12Al14O33 oxide ion conductor, LiCoMnO4 lithium battery cathode, doped Li4SiO4 tunable lithium ion conductor, and La-doped BaTiO3 ferroelectric, which can be either semiconducting or insulating. Examples are also given of a curious observation that extraordinary properties are often encountered in materials that are on the edge of stability, either structurally or compositionally or at the crossover between different property types.