NdCl3-FeCl3-石墨层间化合物的合成

采用熔盐交换法成功地合成了ＮｄＣｌ３ＦｅＣｌ３ＧＩＣ, 用ＸＲＤ 技术和Ｘ射线能谱仪（ＥＤＳ） 对其层间结构及各元素的相对含量进行了表征。研究表明, 其结构为２,３ ,４ 阶混合结构,３ 阶ＮｄＣｌ３ 的特征层间距为１－６５３６ ±０－００２４ ｎｍ , 并探讨了稀土氯化物石墨层间化合物的形成机制。     

石墨层间化合物FeCl3-CrO3-GIC的制备及性能研究

以天然鳞片石墨、CrO₃、CH₃NO₂、FeCl₃为原料，按物质的量的比34∶1.5∶22∶1，利用化学氧化法制备出低温易膨胀、高膨胀容积的石墨层间化合物，300 ℃时膨胀容积为420 mL·g^-1，800 ℃时达到最大膨胀容积630 mL·g^-1，明显优于传统硫酸、硝酸插层的石墨层间化合物。采用SEM、EDS、FTIR、XRD、TG、VSM等技术对石墨层间化合物的组成、结构、性能进行了表征和分析。     

NdCl3-FeCl3-石墨层间化合物的XPS研究

通过熔盐交换法合成了ＮｄＣｌ３－ＦｅＣｌ３－ＧＩＣ,采用Ｘ射线电子能谱（ＸＰＳ）分析插入剂在石墨层间的存在形式,并测定了试样中Ｎｄ,Ｆｅ,Ｃｌ和Ｃ的相对含量。ＮｄＣｌ３－ＦｅＣｌ３－ＧＩＣ中Ｆｅ２ｐ的结合能为７１１．２０－７１０．３ｅＶ,Ｎｄ３ｄ的结合能为９８３．２０－９８３．０８ｅＶ,并发现Ｆｅ在石墨层ｅ＾３＋,Ｆｅ＾２＋形式存在。     

金属石墨层间化合物的量子化学和热力学研究

采用量子化学密度泛函B3LYP方法,对碱金属、碱土金属和过渡金属石墨层间化合物(A-GIC,AE-GIC和T-GIC)进行计算.从原子净电荷、Mulliken重叠布居和轨道电子数等角度讨论了A-GIC和AE-GIC的电子结构与成键特性,初步阐明了结构与性能的关系.根据计算结果,结合热力学分析,讨论实验上尚未知的过渡金属石墨层间化合物合成的可能性.     

磷酸铵与多聚磷酸铵插层可膨胀石墨的制备

Expandable graphite intercalated by ammonium phosphate (AP) or ammonium polyphosphate (APP) was prepared by direct intercalation and two-step method, respectively. The products from two-step method show higher expansion volume, more weight increase and more weight loss after expansion, suggesting that the two-step method is a favorable method for preparation of APP intercalated EG. XRD provides convincing evidence for successful formation of APP-EG by showing strong diffraction peak at much lower 2θ angle. Scanning electron microscopy (SEM) with energy dispersive X-ray Spectroscopy (EDS) gives more evidence for intercalation of APP in the graphite layers.     

增大层间距对天然石墨可逆储锂性能的影响研究

利用石墨嵌入化合物(GIC)制备技术处理天然石墨, 然后在其表面包覆一层软炭前驱体, 并在惰性气氛下热处理. 所得样品不但层间距保持了拉大的状态, 而且还在天然石墨内部预留了膨胀空间. 成功地找到了在保持天然石墨粒度和碳六角平面直径不显著改变情况下, 提高石墨层间距, 预留膨胀空间的石墨改性方法. 分析表明, 石墨嵌入化合物表面含有的大量含氧官能团, 在软炭前驱体包覆石墨嵌入化合物的过程中, 含氧官能团与沥青之间的反应和石墨嵌入化合物分解产生气体的溢出阻碍了层间距和预留空间的恢复. 将这种材料用于锂离子电池负极材料, 石墨的可逆储锂容量变化不大, 但是倍率放电性能和循环性能得到明显改善. 这主要是因为加大层间距和预留膨胀空间, 拓宽了锂离子扩散通道, 降低了石墨嵌锂膨胀引起的包覆层破裂.     

NdCl3-FeCl3-石墨层间化合物的合成及结构模型

通过扫描电子显微镜(SEM)和能谱分析(EDS)研究了NdCl3-FeCl3-石墨层间化合物的微观形貌和元素分布. 结果表明, Nd元素插入石墨层间并形成了NdCl3-FeCl3-石墨层间化合物, 同时发现在石墨中Nd, Fe元素分布均匀. 在此实验基础上, 建立了稀土氯化物(RECl3)插入石墨的结构模型; 依据模型, 计算了RECl3-石墨层间化合物的特征层间距dPP值和间隔能指数, 计算值与实验值吻合较好, 其相对误差约为±2%; 并且发现TbCl3～LuCl3以(001)晶面插入石墨层间时, 其所需间隔能最小, 而LaCl3～GdCl3以(111)晶面为最优取向.     

层间化合物hNB—Cu稳定性的理论研究

以分子簇为模型，用从头算方法，在６－３１Ｇ＾＊基组水平上对六方氮化硼（ｈＢＮ）进行几何全优化，再用优化构型对Ｃｕ的六方氮化硼层间化合物（ｈＮＢ－Ｃｕ）做单点计算，根据计算结果，从层间距、Ｍｕｌｌｉｋｅｎ布居、轨道相互作用、原子净电荷及前线轨道等角度分析了ｈＢＮ－Ｃｕ的电子结构及其稳定性，通过劝分析计算确认了这一层间化合物只是一个介稳结构，阐明了Ｃｕ使六方氮化硼陶瓷致密化的作用机理以及ｈＮＢ－Ｃｕ的弱抗氧化性。     

六方氮化硼与石墨在形成层间化合物上的差异的理论研究

根据量子化学密度泛函B3LYP方法的计算结果,从六方氮化硼(h-BN）与石墨的前线轨道能级和两对离子探针（C^ 和C^-）的作用能所表现出来的在电亲和性上的差异以及金属层间化合物的电子结构,分析了h-BN不能形成金属层间化合物的原因。     

富烯碳原子簇的石墨层间闭合形成机理

本文提出了富烯碳原子簇的石墨层间闭合形成机理，由该机理推出的许多结果与实验事实符合很好。我们认为碳原子簇自由基的快速淬灭及其淬灭速度是富烯碳原子簇形成及其丰度的决定因素。由此得出富烯碳原子簇在给定实验条件下产生的必然性，并预言不同大小的富烯碳原子簇可以通过优化实验条件选择性地合成。     

Thermal Decomposition of Ternary Sodium Graphite Intercalation Compounds

Graphite intercalation compounds (GICs) are often used to produce exfoliated or functionalised graphene related materials (GRMs) in a specific solvent. This study explores the formation of the Na-tetrahydrofuran (THF)-GIC and a new ternary system based on dimethylacetamide (DMAc). Detailed comparisons of in situ temperature dependent XRD with TGA-MS and Raman measurements reveal a series of dynamic transformations during heating. Surprisingly, the bulk of the intercalation compound is stable under ambient conditions, trapped between the graphene sheets. The heating process drives a reorganisation of the solvent and Na molecules, then an evaporation of the solvent; however, the solvent loss is arrested by restacking of the graphene layers, leading to trapped solvent bubbles. Eventually, the bubbles rupture, releasing the remaining solvent and creating expanded graphite. These trapped dopants may provide useful property enhancements, but also potentially confound measurements of grafting efficiency in liquid-phase covalent functionalization experiments on 2D materials.     

Model for the Thermal Expansion of Modified Graphite Nitrates

The thermal expansion of modified graphite nitrates was studied under close-to-equilibrium conditions. A model was proposed based on the expansion of a cavity in the sample similar to a Griffith crack. In accord with this model, the increase in the volume of the sample is proportional to the sixth power of the temperature due to the synergistic action of three factors: 1) accumulation of gas in the cavity, 2) increase in the temperature, and 3) decrease in the limiting pressure that the cavity can withstand without expanding.     

Investigations of Deintercalation Processes in Graphite Intercalation Compounds With SbCl5 and ICl

Results of the investigations of deintercalation process in intercalation compounds graphite-SbCl₅ and graphite-ICl are presented. It was found that sample mass losses have a step character that testifies to the discrete transition from one stage of graphite intercalation compounds to another. The increase in the rate of heating breaks the step character of mass loss dependence on temperature and intensive mass losses occur without stage transitions. This revised version was published online in August 2006 with corrections to the Cover Date.     

氧化铜和聚磷酸铵对聚酰胺6热降解行为的影响

氧化铜和聚磷酸铵对聚酰胺6热降解行为的影响     

TG-FTIR studies on lignin-based polycaprolactones

Thermal degradation behaviour of alcoholysis lignin-based polycaprolactones (ALPCL's) with various molar ratios of β-caprolactone monomer to each hydroxyl group of lignin (CL/OH ratios) was studied by TG-FTIR. The temperature was varied from 20 to 800°C. Thermal degradation temperatures (T_d's) of alcoholysis lignin (AL) and ALPCL's were determined using TG curves. T_d increased with increasing CL/OH ratio, suggesting that AL becomes thermally stable after the derivatization with PCL chains. Mass residue (MR) at 500°C was also determined using TG curves. MR values decreased with increasing CL/OH ratios. The evolved gases formed by thermal degradation of ALPCL's at various temperatures were simultaneously analyzed by FTIR. The main peaks observed for the samples are as follows: wavenumber (assignment): 1160 cm^-1 (vC-O-), 1260 cm^-1(-C(=O)-O-C-), 1517 and 1617 cm^-1 (vC=C), 1770 cm^-1 (vC=O), 2345 cm^-1 (vCO2), 2945 cm^-1 (vC-H) and 3700 cm^-1 (vOH). It was found that the peak intensities for C=O, CH, C-O-C, OH peaks, which were observed for evolved gases at 430°C, increased with increasing CL/OH ratios, suggesting that the evolved gases at 430°C are mainly formed by thermal degradation of PCL chains in ALPCL's. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal degradation of PVC cable insulation studied by simultaneous TG-FTIR and TG-EGA methods

Thermogravimetry (TG/DTG) coupled with evolved gas analysis (MS detection) of volatiles was used to characterize the thermal behavior of commercial PVC cable insulation material during heating in the range 20-800°C in air and nitrogen, respectively. In addition, simultaneous TG/FTIR was used to elucidate chemical processes that caused the thermal degradation of the sample. A good agreement between results of the methods was found. The thermal degradation of the sample took place in three temperature ranges, namely 200-340, 360-530 and 530-770°C. The degradation of PVC backbone started in the range 200-340°C accompanied by the release of HCl, H₂O, CO₂ and benzene. The non-isothermal kinetics of thermal degradation of the PVC cable insulation in the temperature range 200-340°C was determined from TG results measured at heating rates of 1.5, 5, 10, 15 and 20 K min^-1 in nitrogen and air, respectively. The activation energy values of the thermal degradation process in the range 200-340°C of the PVC cable insulation sample were determined from TG results by ASTM method. This revised version was published online in July 2006 with corrections to the Cover Date.