含间位取代苯基聚醚酮酮的结晶与晶体结构研究

通过差示扫描法（ＤＳＣ）及广角Ｘ 射线衍射（ＷＡＸＤ）技术研究了含间位取代苯基聚醚酮酮（ＰＥＫｍＫ）的结晶行为与晶体结构．Ｘ 射线结果表明，从熔融态及玻璃态结晶时，ＰＥＫｍＫ只有一种晶型，其晶胞参数为：ａ＝０７６７２ｎｍ，ｂ＝０６１４９ｎｍ，ｃ＝１５９９ｎｍ．ＤＳＣ结果表明，ＰＥＫｍＫ热分析曲线都出现了熔融双峰，低熔融峰（ＤＯＷｎ）热焓占总热焓４～７％，它源于初始结晶形成的同一晶型不同厚度片晶．低熔融峰在２５０℃以上结晶转化成高熔融峰（Ｉ），ＰＥＫｍＫ平衡熔点为２９５℃     

(Ce_(0.67)Tb_(0.33))MgAl_(11)O_(19)和BaMgAl_(10)O_(17)∶Eu~(2 )荧光体的微波辐射合成及其发光性能

用微波辐射法合成了（Ｃｅ０．６７Ｔｂ０．３３）ＭｇＡｌ１１Ｏ１９（ＰＧ）和ＢａＭｇＡｌ１０Ｏ１７（ＰＢ）两种荧光体，经Ｘ射线粉末衍射分析，其ｄ值和Ｉ／Ｉ０值与ＪＣＰＤＦ３６７３和２６１６３基本一致。计算得到ＰＧ的晶胞参数ａ＝０５５８２ｎｍ，ｃ＝２１８８４ｎｍ；Ｐ－Ｂ的晶胞参数α＝０５６１６ｎｍ，ｃ＝２２６１４ｎｍ。测定了两种荧光体的激发光谱和发射光谱。Ｐ－Ｇ的色坐标ｘ＝０３１６，ｙ＝０５６５；Ｐ－Ｂ的色坐标ｘ＝０１５６，ｙ＝０１０６。与市售同类荧光粉相比，Ｐ－Ｇ的相对发光强度为８８％，Ｐ－Ｂ的相对发光强度为８０％。     

二次锂电池正极材料Li_xNi_（0．3）Co_（0．7）O_2的XPS与XRD

结果表明，ＬｉｘＮｉ０．３Ｃｏ０．７Ｏ２具有六方晶系Ｒ３－ｍ空间群结构。当Ｘ＝１，０．３１５时，其晶胞参数分别为ａ＝２．８２６ｎｍ，ｃ＝１４．１３０ｎｍ和ａ＝０．２８０８ｎｍ，ｃ＝１．４２５３ｎｍ；ＭＯ６（Ｍ＝Ｎｉ，Ｃｏ）八面体中Ｍ－Ｏ平均距离分别为０．１９４１ｎｍ和０．１９３３ｎｍ。ＸＰＳ分析结果表明ＬＩｘＮｉ０．３ＣＯ０．７Ｏ２表面存在Ｌｉ２Ｏ，同时探讨了其中过渡金属离子的３ｄ电子结构变化。     

二次锂电池正极材料LixNi0.3Co0.7O2的XPS与XRD研究

结果表明，ＬｉｘＮｉ０．３Ｃｏ０．７Ｏ２具有六方晶系Ｒ３＾－ｍ空间群结构。当Ｘ－１，０．３１５时，其晶胞参数分别为ａ＝２．８２６ｎｍ，ｃ＝１４．１３０ｎｍ和ａ＝０．２８０８ｎｍ，ｃ＝１．４２５３ｎｍ；ＭＯ６（Ｍ＝Ｎｉ，Ｃｏ）八面体中Ｍ－Ｏ平均距离分别为０。１９４１ｎｍ和０．１９３３ｎｍ。ＸＰＳ分析结果表明ＬＩｘＮｉ０．３ＣＯ０．７Ｏ２表面存在Ｌｉ２Ｏ，同时探讨了其中过渡金属离子的３ｄ电子结构变化。     

1-[(Z)-2-(-苯基二溴化锡基)乙烯基]环戊醇的合成及晶体结构

通过１［（Ｚ）２（三苯基锡基）乙烯基］环戊醇与Ｂｒ２反应制得了新化合物１［（Ｚ）２（苯基二溴化锡基）乙烯基］环戊醇．通过元素分析、锡含量测定、ＩＲ、１ＨＮＭＲ对其进行了表征并用Ｘ射线衍射法测得了所合成化合物的晶体结构．该化合物属正交晶系，Ｐ２１２１２１空间群，晶胞参数：ａ＝０８６７５（４）ｎｍ，ｂ＝１２５２３（７）ｎｍ，ｃ＝１４００９（８）ｎｍ；Ｚ＝４，Ｖ＝１５２１９ｎｍ３，Ｄｃ＝２．３９ｃｍ３，ｕ＝２３．７２ｃｍ－１．结构分析表明，标题化合物分子为畸变的三角双锥构架，双键的两个氢取顺式结构，分子中Ｏ与Ｓｎ配位，形成五元螯合环结构     

四氢咪啶[2,1—a]并—2,3—二苯基—1,4—二氮杂—3—环己烯…

对由二乙烯三胺与联苯甲酰合成的标题化合物进行了ＭＳ、ＩＲ、ＵＶ、ＮＭＲ谱的表征及Ｘ射线单晶衍射结构分析。该化合物Ｍｒ＝２７７．３９，晶体属Ｐ２１／ｎ空间群，晶胞参数ａ＝０．９４４２（２）ｎｍ，ｂ＝１．４３４４（４）ｎｍ，ｃ＝１．１８２４（３）ｎｍ，β＝１１２．９２（２）°，Ｚ＝４，Ｄｃ＝１．２５ｇ·ｃｍ＾－３。晶体结构由直接法解出，１８２７个可观察衍射参与最小二乘法修正，最终偏差因子Ｒ＝０．０５０     

聚乙烯串晶在单轴拉伸形变过程中的微结构变化和机理

本文采用电子显微镜和小角Ｘ－射线散射（ＳＡＸＳ）技术研究了含有串晶结构（Ｓｈｉｓｈ—ｋｅｂａｂ）的高密度聚乙烯（ＨＤＰＥ）／超高分子量聚乙烯（ＵＨＭＷＰＥ）共混物高取向膜在单轴拉伸过程中的微结构变化．深入探讨了拉伸温度对聚乙烯在形变过程中微结构变化的影响．室温拉伸时，聚乙烯串晶结构主要发生了解结晶过程；高温（１１５℃）形变时，主要表现为折叠链片晶直接转变为伸展链纤维晶的应变诱导结晶过程．     

聚对苯甲酰胺薄膜的结构

聚对苯甲酰胺溶于ＤＭＳＯ ＮａＨ系中，变成聚合物阴离子，形成均相溶液．从此溶液中蒸发掉ＤＭＳＯ，用有机溶剂再生后获得再生薄膜．室温下干燥的薄膜基本上是无定形的，１３０℃的热处理对薄膜的结构几乎不发生大的影响，２５０℃或者３００℃的热处理后，薄膜的结构由无定性变成结晶１型及新的结晶２型．与结晶１型相比，结晶２型的ｄ＝０４９ｎｍ与ｄ＝０２８ｎｍ的反射强烈出现，而且相对于结晶１型的ｄ＝０３１ｎｍ的反射看不见或者看不清楚     

（Ce0.67Tb0.33）MgAl11O19和BaMgAl10O17：Eu^2＋荧光体的微波辐 …

用微波辐射法合成了（Ｃｅ０．６７Ｔｂ０．３３）ＭｇＡｌ１１Ｏ１９（Ｐ－Ｇ）和ＢａｍｇＡｌ１０Ｏ１７（Ｐ－Ｂ）两种荧光体，经Ｘ射线粉末衍射分析，其ｄ值和Ｉ／Ｉ０值与ＪＣＰＤＦ３６－７３和２６－１６３基本一致。计算得到Ｐ－Ｇ的晶胞参数ａ＝０．５５８２ｎｍ，ｃ＝２．１８８４ｎｍ；Ｐ－Ｂ的晶胞参数ａ＝０．５６１６ｎｍ，ｃ＝２．２６１４ｎｍ，测定了两种荧光体的激发光谱和发射光谱，Ｐ－Ｇ的色坐标ｘ＝０．３１６     

双核钨氧柠檬酸配合物K_6[W_2O_5(cit)_2]·6H_2O的合成及晶体结构

标题化合物是通过四硫代钨酸铵和柠檬酸钾反应而得。用ＩＲ、ＸＰＳ、元素分析进行了结构表征，Ｘ－ｒａｙ结构测定进一步肯定了以上结论。该晶体为三斜晶系，Ｐ１空间群，晶胞参数为：ａ＝０．８５１１１（９）ｎｍ，ｂ＝０．９７８４（１０）ｎｍ，ｃ＝１．０８２（１１）ｎｍ，α＝１１４．８５（１２）°，β＝１０６．５８（１１）°，γ＝９８．８９（１０）°，Ｚ＝１，Ｖ＝０．７４３６（１３）ｎｍ３，Ｄｃ＝２．５９４ｇ／ｃｍ３，Ｆ（０００）＝５５４，μ＝８６．６１ｃｍ－１，一致性因子Ｒ＝０．０７５，ＷＲ２＝０．１８８９。     

Influence of draw ratio on morphological and structural changes in hot-drawing of UHMW polyethylene fibres as revealed by DSC

The melting behaviour of gel-spun, ultra-high molecular weight polyethylene fibres was investigated in an attempt to characterize their morphology after various stages of hot-drawing at 148 C. In this drawing process a shish-kebab morphology is transformed into a smooth fibrillar structure. It was concluded that this transition initially proceeds by pulling elastically inactive loops, originally present in the folded chain lamellae of the shish-kebabs, taut between entanglements. Thereafter a considerable amount of entanglements is removed by pulling molecular chain ends through them, until ca. 2.5 entangelements per molecule remain in the ultimately drawn fibres. The fibrils in the fully drawn fibres were found to be composed of chain-extended orthorhombic crystallites with an average length of 70 nm, which are interrupted by defect regions (containing trapped entanglements and chain ends) of about 4 nm in length. If free shrinkage of the fibre was allowed, this structure had an equilibrium melting temperature of 140.5 C. Upon constrained melting of the filaments, a solid-solid phase transition could be observed in the DSC thermograms (at a temperature of ca. 150 C), associated with a transition of the chain-extended orthorhombic blocks in the fibrils into a hexagonal phase. The heat effect associated with this solid-solid transition in perfectly crystalline polyethylene (H _o–h ) was estimated to be 205 kJ/kg, whereas for the heat of fusion of the hexagonal phase (H _h–m ) a value of 81 kJ/kg was assessed.     

天然橡胶在单向拉伸下的结晶与取向

<正> 从研究聚乙烯由球晶结构转变到纤维结构的过程得知,聚乙烯纤维由一束平行排列的细纤维(microfibril)组成,细纤维则由垂直于纤维轴互相平行排列的折迭链块(foldedchain block)组成,折迭链块之间有链段相连.处于高弹态的天然橡胶(-78°—28℃),进行单向拉伸,可发生取向并同时结晶,形成纤维,但是它与聚乙烯的起始态不同,为阐明天然橡胶拉伸后是否也有类似聚乙烯纤维的结构单元,本文采用透射式电子     

Crystal deformation during the growth of kink bands in oriented polyethylene

When oriented polyethylene is sheared at an angle to the orientation axis, kink bands often develop and grow, with a resulting change of the crystalline orientation. Beside the crystalline reorientation, the following changes within the kink bands have been observed with wide-angle x-rays: (a) partial transformation to a monoclinic from the normal orthorhombic unit cell; (b) partial alignment of the orthorhombic b axes; (c) rotation of the orthorhombic c axes of a fraction of the crystals around the kinks by an extra 40 to 60° beyond that of the fibrils; and (d) misalignment of the orthorhombic (hk0) planes by a few degrees. These results are suggested to arise, at least in part, from crystal flattening and from crystal twinning or pseudotwinning on planes intersecting the molecular axes.     

Effect of the Drawing Process on the Thermal Stability of Gelatine-polyacrylonitrile Graft Copolymer Fibres

The thermal stability of gelatine-polyacrylonitrile graft copolymers fibres obtained under various conditions of deformation has been studied. The thermal properties of examined fibres depend on the synthetic component of the fibre forming material – polyacrylonitrile which appears in the form of grafted PAN chains and PAN homopolymer. It was stated that the highest thermal stability have those fibres which formation process included two stages of drawing with the use of deformation close to the maximal values, with the value of the total draw ratio amounting to 691%. It should be supposed that with such a drawing process, already in its first stage, are created advantageous conditions for the formation of paracrystalline regions to a larger extent and their orientation along the fibre axis. This revised version was published online in August 2006 with corrections to the Cover Date.     

Dye diffusion in anisotropic polyamide fibres

Radioactive tracer techniques have been used to study the diffusion of three dyes in polyamide fibres produced under different conditions. It has been shown that drawn nylon fibres have a surface barrier layer which limits diffusion. The permeability of the layer is reduced by drawing, and varies with drawing conditions. The dependence of dye diffusion on concentration, ionic size and draw ratio is less in the surface than in the bulk of the fibre, but variations in dyeing behaviour have been shown to follow surface rather than bulk diffusion characteristics.     

Influence of drawing and heat treatment on surface free energies of polyethylene terephthalate fibers

The surface free energies of polyethylene terepthalate fibers with different draw ratios were experimentally determined by contact angle measurements inn-alkane/water systems. The dispersive component of the surface free energy increased with increasing draw ratio, whereas the nondispersive one remained almost constant. After heat treatment, the dispersive surface free energy increased, but was reduced above 140°C. The nondispersive component increased by heat treatment at 190°C. The increases in the density and birefringence of the fibres due to the drawing and heat treatment suggested that the increase in the dispersive surface free energy was caused by the increase in the atomic density at the fiber surface due to drawing and heat treatment. ESCA results indicated that the increment in the nondispersive surface free energy due to heat treatment was caused by the addition of functional groups to the fiber surface due to heat treatment.     

Two-beam interference detection of the changes in fibre structural parameters during low drawing process

A Pluta polarizing interference microscope with a fibre stretching device attached was used to detect the changes in molecular structure that occur during the fibre cold drawing process. Fibres drawn with low draw ratios show different types of deformation mechanisms. The interference patterns recorded at different draw ratios are used to relate the deformation mechanisms with the measured structural parameters. Some optical parameters are measured such as; refractive indices nand n birefringence n, the polarizability per unit volume , the orientation distribution function f(θ), the angle θ between the stretching direction and the chain axis, and the angle θ_m which the transition dipole moment of the molecular species makes with the molecular axis (chain axis). Three polymeric fibres (Polyethylene terephthalate PET, Polypropylene PP and Polyamide PA) were used in this study and their interferograms are illustrated.     

Thermal properties of fibres from a new polymer of the polyimideamide group

The paper presents the thermal properties of fibres made of a modified polyimideamide. The effects of as-spun draw ratio and deformation during the fibre drawing stage on the structure, thermal properties, moisture absorption and tenacity of the obtained fibres have been determined. Based on the findings obtained by the DTA and DSC methods, it has been found that the modification of the polymer under investigation causes its glass transition temperature to decrease through the increase of molecular mobility. At the same time, the heat-resistant fibres with the amorphous oriented structure are characterized by a tenacity of 16 cN/tex, good absorption properties and increased porosity. The thermal stability indices of the examined fibres have been determined on the basis of thermogravimetric curves obtained both under air and inert gas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Study of β relaxation in polypropylene fibres modified by several techniques

Polypropylene fibres prepared from polypropylene (PP) blended with 8 wt% of an ethylene aminoalkylacrylate copolymer were studied by means of ¹H nuclear magnetic resonance (NMR) and dynamic mechanical techniques. Measurements were carried out on the fibres spun at the spinning speeds 400 and 1200 m.min⁻¹ and then drawn to the draw ratio λ = 3.5. Spin ‐ lattice relaxation time T₁ and storage E' and loss E'' components of a dynamic mechanical modulus were measured in the temperature region of the glass transition. Broad line NMR spectra were detected at 313 K. The experimental results show that drawing of the fibres prepared at both spinning speeds results in a restriction of the molecular motion. Simultaneously with the restriction, a chain mobility enhancement was observed in noncrystalline regions of the fibres. Similar effects were induced also by rising the spinning speed. Reasons for this behavior are discussed in the paper.     

Effect of preparation of sol-gel coatings on the strength of optical fibres

SiO₂, TiO₂, ZrO₂, and TiO₂-ZrO₂ thin coatings were applied by sol-gel method on quartz fibres during the fibre drawing. Durable layers with the thicknesses up to 0.7 m were obtained. The layer smoothness and thickness were determined using electron microprobe analyzer and electron or optical microscopy. In order to investigate a decrease in the strength of sol-gel coated fibres a novel method employing silica capillaries was developed. The fibre strength decrease was explained by the influence of water penetrating as a result of the coating process into the flaws on the fibre surface.