三硒化二铒Er_2Se_3的合成与结构

采用高温固相反应和化学气相传输法合成三硒化二铒。晶体属于四方晶系，Ｍ_ｒ＝５７１．４０，空间群为Ｐ４／ｎｍｍ，ａ＝３．９８４（１），ｃ＝８．２２８（３），Ｖ＝１３０．５９（７），Ｚ＝１，Ｄ_ｃ＝７，２７ｇ／ｃｍ￣３，Ｆ（０００）＝２３８，μ（ＭｏＫα）＝５２８．８６ｃｍ￣（－１），对于１８７个Ｉ≥３σ（Ｉ）的独立衍射点，最后偏离因子Ｒ＝０．０６６，Ｒ_ｗ＝０．０７８。化合物Ｅｒ_２Ｓｅ_３的晶体结构是由Ｅｒ配位多面体的双层状结构通过共用Ｓｅ（２）原子，沿ｃ轴方向堆积而形成的三维结构。     

［Vmo_3O_4（O_2CEt）_8］_2Na_2的合成与结构

［ＶＭｏ３Ｏ４（Ｏ２ＣＥｔ）８］２Ｎａ２（１），三斜晶系，Ｐ１空间群，ａ＝１２．９７７（７），ｂ＝１４．０７０（６），ｃ＝１２．３３８（８），α＝１０９．８１（４），β＝１１７．２０（４），γ＝９０．５１（５）°，Ｖ＝１８４８．８３，Ｍｒ＝２０２０．６，Ｄｃ＝１．８１ｇ／ｃｍ３，Ｚ＝１，Ｆ（０００），μ＝１２．９ｃｍ１（ＭｏＫα）对３７４２个可观测反射点（Ｉ＞３σ（Ｉ））最终一致性因子为Ｒ＝０．０１８，Ｒω＝０．０５４。单晶结构分析表明，簇阴离子中两个［Ｍｏ３Ｏ４］４＋单元通过两个＂桥＂金属Ｖ原子连接成一个奇特的环状结构，Ｍｏ－Ｍｏ平均键长为２．５１９（１），Ｍｏ…Ｖ间平均距离为３．６５４。簇阴离子通过Ｎａ＋连成一个一维长链，Ｎａ原子与氧原子形成一个少见的五配位三角双锥结构，Ｎａ－Ｏ距离仅为２．３１２，Ｎａ－Ｏ间较强的相互作用以及无限长链的晶体结构很好地解释了簇合物（１）的稳定性和不溶性。     

氰尿酸钡的晶体结构

报道了氰尿酸钡［Ｂａ（Ｃ_３Ｈ_２Ｎ_３Ｏ_３）_２·（Ｈ_２Ｏ）_２］的晶体结构。晶体属三斜晶系，空间群为Ｐ１，晶胞参数为：ａ＝８．８８４（３）．ｂ＝９．４２２（４），ｃ＝７．２０１（４）Ａ，α＝９７．７５（４），β＝１０１．７６（４），γ＝８５．０５（３）°；Ｍ_ｒ＝４２９．４９，Ｚ＝２，Ｄ_ｃ＝２．４４ｇ／ｃｍ~３。Ｖ＝５８３．６（４）Ａ~３，μ＝３４．５６ｃｍ~（－１），λ（ＭｏＫα）＝０．７１０６９Ａ，Ｆ（０００）＝４１２，Ｉ＞３σ（Ｉ）的衍射点２０９１个。结构用ＴＥＸＳＡＮ程序包以直接法解出，经全距阵最小二乘法修正，最后Ｒ因子为０．０２９，Ｒ_ω＝０．０３７．中心离子Ｂａ~（２＋）的配位数为１０，Ｂａ~（２＋）离子处于６个配位原子形成的平面的中心位置上，另外４个配位原子则处于平面外，分布在Ｂａ~（２＋）离子的周围。     

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℃     

氰尿酸镍的晶体结构

标题化合物Ｎｉ（Ｃ＿３Ｈ＿２Ｎ＿３Ｏ＿３）＿２（Ｈ２Ｏ）＿４属正交晶系，空间群为Ｆｍｍｍ（编号６９）。晶胞参数：ａ＝７．２８２（４），ｂ＝１２．０５７（２），ｃ＝１６．０７２（２），Ｖ＝１４１１（１），Ｄ＿ｃ＝１．８２ｇ／ｃｍ￣３，Ｚ＝４，Ｍ＿ｒ＝３８６．８９，λ（ＭｏＫα）＝０．７１０６９，μ＝１４．４３ｃｍ￣（－１），Ｆ（０００）＝７９２。最终偏离因子Ｒ＝０．０４５，Ｒ＿ｗ＝０．０６０。独立可观测点数（Ｉ≥３σ（Ｉ））为３８５个。在配合物中，镍离子与来自氰尿酸的两个氮原子和来自水分子的四个氧原子配位。     

呋喃醛双缩二氨基硫脲腙的合成和结构测定

由ＣＳ＿２，Ｎ＿２Ｈ＿４和Ｃ＿４Ｈ＿３ＯＣＨＯ合成Ｃ＿（１１）Ｈ＿（１０）Ｎ＿４Ｏ＿２Ｓ·１／２ＤＭＦ，Ｍ＿ｒ＝２９８．７９，橙黄针状晶体，三斜晶系，空间群Ｐ１，ａ＝８．９１２（３），ｂ＝９．９８９（３），ｃ＝１６．１０７（４），ａ＝８３．６１８（６），β＝８７．１０５（５），γ＝８６．１１５（３）°，Ｖ＝１４２０．４，Ｚ＝４，Ｄ＿ｘ＝１．３９７ｇ／ｃｍ￣３，λ（ＭｏＫα）＝０．７１０７３，μ＝２．１７０ｃｍ￣（－１），Ｆ（０００）＝６１６。３２２６个可观察的独立反射（Ｉ＞３σ（Ｉ）使结构顺利解出，并精修到Ｒ＝０．０４８，△ρ＿（ｍａｘ）＝０．２８６。单晶体结构分析表明不对称单位含有二个非结晶学对称相关的独立分子和一个溶剂分子ＤＭＦ，通过ＤＭＦ中的ｏ原子和亚胺Ｈ形成Ｎ－Ｈ…Ｏ…Ｈ－Ｎ类型双氢键，使两个分立分子缔合一起而自成独立的结构单元。     

酞菁锰-表面活性剂薄膜电极的电化学表征及其对三氯乙酸的电化学催化作用的研究

将酞菁锰（ＭｎＰｃ）掺入阳离子表面活性剂双十二烷基二甲基溴化铵（ＤＤＡＢ）的氯仿溶液，并涂布于热解石墨电极表面，待氯仿挥发后即制得ＭｎＰｃ－ＤＤＡＢ薄膜电极。循环伏安实验表明，在ＫＢｒ溶液中，该薄膜电极有两对还原氧化峰，第一对峰的Ｅｐｃ１＝－０．２７Ｖ，Ｅｐａ１＝０．０１Ｖ；第二对峰的Ｅｐｃ２＝－０．７６Ｖ，Ｅｐａ２＝－０．６２Ｖ（ｖｓ．ＳＣＥ）。本文着重探讨了第二对峰的电化学行为，估计了该体系的电荷传递扩散系数Ｄｃｔ和表观非均相电极反应速率常数Ｋ０′等电化学参数，并可将该薄膜电极用于催化三氯乙酸的电化学还原。     

Eu（β－NMA）_3PHEN的晶体结构及光谱研究

标题化合物Ｍ＝８４５．６９，三斜晶系，空间群，ａ＝１．１７１８（２）ｎｍ，ｂ＝１．５６７０（３）ｎｍ，ｃ＝１．０００２（２）ｎｍ，α＝９９．９７（１）°，β＝９０．１３（１）°，γ＝９８．３６（２）°，Ｖ＝１．７８８９（５）ｎｍ~３，Ｚ＝２，Ｆ（０００）＝８４８，Ｄ_ｘ＝１．５７ｇ·ｃｍ~３，λ（ＭｏＫα）＝０．０７１０６９ｎｍ，μ＝１８．０６ｃｍ~（－１），Ｔ＝２９５Ｋ，Ｒ＝０．０４０．中心Ｅｕ（Ⅲ）离子与周围６个氧和１对氮原子配位，配位多面体属四方反棱柱体，其点对称性为Ｃ_１。     

簇合物〔WOS_3Cu_3(V-pic)_6〕Br 的合成和晶体结构

簇合物〔ＷＯＳ３Ｃｕ３（γ－ｐｉｃ）６〕Ｂｒ（Ｃ３６Ｈ４２ＢｒＯＮ６Ｓ３Ｃｕ３Ｗ, Ｍｒ＝ １１２５．３４） 属于三方晶系,空间群为Ｐ３,晶胞参数为：ａ＝ １２．２６４（５）, ｃ＝ １５．９０５（８） , γ＝ １２０．００°, Ｖ＝２０７１（２）３, μ（ＭｏＫα）＝ ５．４９０ｍ ｍ － １, Ｚ＝ ２, Ｄｃ＝ １．８０４ｇ／ｃｍ ３, Ｆ（０００）＝ １１０４ , Ｒ＝ ０．０５２ , ｗ Ｒ＝ ０．０５３． 可观察衍射点１９０１ （Ｉ≥２σ（Ｉ））。该簇合物的分子由游离的阴离子Ｂｒ－ 和簇阳离子〔ＷＯＳ３Ｃｕ３（γ－ｐｉｃ）６〕＋ 构成。阳离子中的Ｗ 原子、Ｓ原子和Ｃｕ原子构成１ 个巢状骨架结构,且该结构中存在一个通过Ｗ 和Ｏ原子的Ｃ３ 轴。     

CDF分析方法研究取向非晶PET的结构

用对称透射法收集聚酯(PET)单轴拉伸取向非晶薄膜样的二维广角X射线散射强度I_C(K,(?)),将不同方位角(?)上的I_C(K,(?))非晶重叠峰曲线进行计算机分峰,获得伊易空间中分子链间原子散射引起的2个主峰:K_A(K=0.122),K_B(K=0.171),分子链内原子散射引起的2个主峰;K_C(K=0.310),K_D(K=0.548).进一步通过抽样转换法由强度函数I_E(K,(?))计算出实空间的圆柱分布函数CDF(R,α),得到与K_A,K_B,K_C和K_D峰对应的实空间的峰依次为R_A(R=0.658),R_B(R=0.456),R_C(R=0.253)和R_D(R=0.152).从理论上分析了上述相应峰在倒易空间和实空间中的等效关系及其分布特征,以及引起这些峰的结构起源,详细地研究了取向非晶PET的细微结构信息.     

Structural study of oriented non-crystalline PET by CDF method

The two-dimensional wide angle X-ray scattering (WAXS) intensities of oriented non-crystalline polyethylene terephthalate (PET) films extended umaxially are collected by the symmetrical transmission method; he-sides,the overlapped non-crystalline peaks at WAXS intensity curves,I(K) obtained at different azimuthal angles are also separated by computer,resulting in two peaks caused by interchain atomic scattering in the reciprocal space,KA(K=0.122),KB(K=0.171),and the other two peaks from intracham atomic scattering,Kc(K=0.310) and KD(K=0.548); their cylindrical distribution functions (CDF),CDF(R,α) in the real space are further calcu lated from the intensity functions,IE(K) using sampled transforms,thereof arising in turn the peaks in the real space as,RA(R=0.658),RB(R=0.456),RC(R=0.253) and RD(R=0.152),corresponding to KA,KP,K,and KD The equivalent relationships and distribution characteristics of the above-mentioned corresponding peaks in the reciprocal and real space,as well as their sources of struc     

Confirmation of a nanohybrid shish‐kebab (NHSK) structure in composites of PET and MWCNTs

Here, the confirmation of an oriented nanohybrid shish‐kebab (NHSK) crystalline structure in a series of composites of poly(ethylene terephthalate) (PET) and multiwall carbon nanotubes (MWCNTs) is reported. The combined use of small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) and thermal analysis has been used to investigate the morphology development in PET‐MWCNT nanocomposites under hot isothermal crystallization conditions. The MWCNTs act as both heterogeneous nucleating agents and surfaces (oriented shish structures) for the epitaxial growth of PET crystallites (kebabs) giving an oriented crystalline morphology. In contrast, the PET homopolymer does not show any residual oriented crystalline morphology during isothermal crystallization but gave a sporadic nucleation of a classic unoriented lamellar structure with slower crystallization kinetics. The results provide a valuable insight into the role of MWCNTs as nanoparticulate fillers in the morphology development and subsequent modification of physical properties in engineering polymers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 132–137     

Oriented and thermal crystallization of poly(ethylene terephthalate)

The oriented and thermal crystallization of amorphous poly(ethylene terephthalate) (PET) films was investigated in terms of the morphological aspects. When the amorphous PET films were stretched up to the desired draw ratios in a hot water bath at 62, 72, and 80 °C, the birefringence of the specimens increased with increasing draw ratio (λ). This tendency becomes most significant when the specimen was drawn in the bath at 62 °C. The storage modulus of the specimen drawn at 62 °C was higher than those of the specimens drawn at 72 and 80 °C. The exothermic peak in the DSC curves was observed clearly for the specimen drawn up to λ=4 in the hot water bath at 80 °C, while the peak did not appear for the specimen drawn up to λ=4 at 62 °C. Under an H_v polarization condition, light scattering patterns from the specimens drawn in the hot water bath showed four lobes at small azimuthal angles and four sharp streaks at large azimuthal angles. Such a profile was independent of the drawing temperatures from 62 to 80 °C. Based on the observed H_v patterns, a model was proposed by assuming the existence of a row-nucleated sheaf-like structure whose rows were preferentially oriented at a particular angle with respect to the stretching direction. The patterns calculated by using the above model were rather close to the patterns observed. This agreement implies that row-nucleated sheaf-like texture arises with lamellar overgrowth.

     

Studies of miscibility,transesterification and crystallization in blends of poly(ethylene terephthalate) and Poly(ethylene-2,6-naphthalene dicarboxylate)

Blends of poly(ethylene terephthalate) (PET) and poly(ethylene-2,6-naphthalene dicarboxylate) (PEN) were obtained by coprecipitation from solution followed by melt-pressing for different timest _mand quenching in iced water. When the melt-pressing time was 0.2 and 0.5 min, two glass transition temperaturesT _gwere observed by means of dynamic mechanical analysis (DMA), indicating that there are two phases present, a PEN-rich phase and a PET-rich phase. The differential scanning calorimetry (DSC) curves show two crystallization peaks and two melting peaks which, according to wide-angle x-ray scattering (WAXS) measurements, can be attributed to PET and PEN, respectively. In the case oft _m=2 min or longer, a single value ofT _gand thus a single phase is found to exist. Fort _m=10 min and 45 min no crystallization and melting at all is observed during heating with 10°C/min, indicating that a copolyester of PET and PEN has been formed by transesterfication during melt-pressing.Time-resolved WAXS measurements during isothermal crystallization show that, in the blend, the half-time of crystallization of PET is different from that of PEN, and not the same as that which is found in the pure polymer.Dedicated with best wishes to Prof. Dr. E.W. Fischer on the occasion of his 65th birthday     

Crystalline β‐structure of PHBV grown epitaxially on silicate layers of MMT

The poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV)/montmorillonite(MMT) nanocomposites were investigated by wide‐angle X‐ray scattering (WAXS). The aim of the investigation was solution intercalation of MMT with PHBV. Beside the usual orthorhombic unit cell, a stable pseudohexagonal β‐structure of PHBV was obtained. Well known β‐structure has one common WAXS reflection (d = 0.480 nm), which corresponds to the mean distance of PHBV chains in the pseudohexagonal structure. The new β‐structure has two diffraction peaks in the WAXS pattern. It is a three‐dimensionally ordered crystalline structure oriented in parallel with the silica layers of MMT. The new polymorphic form is supposed to be growing on the layers of MMT. Its layers serve as primary nucleation centers for epitaxial growth of the β‐structure. After annealing, this polymorphic form of PHBV disappears and it is transformed into the more stable α‐form leading to an enhanced total crystallinity of the polymer comprised in the nanocomposite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 751–755, 2009     

Microstructure rearrangement during the heat-treatment of melt-drawn poly(ethylene terephthalate) fibers

Melt-spun poly(ethylene terephthalate) fibers were isothermally heat-treated at constant length. Microstructural changes occurring during the heat-treatment were monitored using specific gravity, wide-angle x-ray scattering (WAXS), small-angle x-ray scattering (SAXS), optical birefringence, and static mechanical testing. Major changes in the density of the most highly oriented fiber examined occurred in times below 100 ms. For less oriented fibers, the time scale for significant density change increases to the 1–10 s range. The course of birefringence increase approximates that of the density. WAXS measurements show that crystallinity develops at essentially constant crystal perfection, but that the orientation of the crystallites first decreases and then increases with time. SAXS results show development of a four-point pattern, the azimuthal angle of the lobes decreasing with initial orientation, with temperature, and with time. A streak transverse to the fiber axis develops more rapidly than do the lobes. A two-stage transformation process is envisaged, the first stage being the formation of defective crystal fibrils and the second being internal rearrangement of the fibrils to form more perfect crystallites, separated by more amorphous zones. Changes in the crystallite orientation are related to constraints of the noncrystalline material on the crystallites.     

Influence of cobalt complex on thermal properties of poly(ethylene terephthalate)/polycarbonate blend

The effects of processing time and concentration of cobalt acetylacetonate III complex in poly(ethylene terephthalate)/polycarbonate reactive blending were investigated. The blend was prepared in an internal mixer at 270°C, 60 rpm, at different processing times (5–20 min) and catalyst concentration (0.00625–0.075 mass%). The reaction product was evaluated by differential scanning calorimetry (DSC), thermogravimetry (TG) and wide angle X-rays scattering (WAXS). In general, the DSC curves showed two glass transition temperatures (T _g’s) close to each homopolymer, independent of the processing time and complex’s concentration, suggesting the presence of two phases: one rich in PET and other one rich in PC. In all cases, melting temperature (T _m), cold crystallization temperature (T _cc) and crystallinity degree (X _c) were progressively reduced with blending conditions. The TG curves presented two decays. The first one represented the PET rich phase and the other one was related to the PC phase. The WAXS diffractograms showed that the Bragg’s angle and interplanar spacing of PET remaining practically unchanged.     

Phase transitions in poly(heptane-1,7-diyl biphenyl-4,4′-dicarboxylate). SAXS,WAXS and DSC study

The main-chain thermotropic liquid-crystalline poly(heptane-1,7-diyl biphenyl-4,4′-dicarboxylate) (P7MB) was investigated by time-resolved small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and differential scanning calorimerty (DSC). Nonisothermal crystallisation with different rates of cooling and heating was used. On cooling, two phase transitions are observed, isotropic melt - smectic (I-Sm) and Sm- three-dimensional crystalline structure (Sm-Cr), whereas on heating only one transition is observed, Cr-I transition. The transition enthalpies were calculated. Temperature dependences of d-spacings of all crystalline peaks and of the peak observed at high values of scattering vector in the SAXS region were derived. The temperature dependence of the degree of crystallinity was established, based on the integrated intensities of the crystalline peaks and amorphous halo in WAXS.     

Integrated mechanism for the morphological structure development in HDPE melt‐blown and machine‐direction‐oriented films

The morphologies of a series of blown films and machine‐direction‐oriented (MDO) films, all produced from high density polyethylene, were characterized. In the blown film process, the crystalline morphology develops while the melt is under extensional stress. In the MDO process, drawing takes place in the solid state and deforms the crystalline morphology of the starting film. The films were characterized by wide‐angle X‐ray scattering (WAXS), small‐angle X‐ray scattering (SAXS) and atomic force microscopy to determine the lamellar morphology. The effect of the type of deformation on the lamellar morphology was studied and relationships were developed between the lamellar and polymer chain morphology using SAXS and WAXS. Blown and MDO films were found to have very different morphologies. However, an integrated mechanism was developed linking the sequential events in the deformation and morphology development in blown and MDO films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1834–1844, 2007     

Kinetics of fiber heat treatment. II. Poly(ethylene terephthalate) fibers

Microstructural changes occurring during the process of crystallization in as-spun poly(ethylene terephthalate) (PET) have been monitored using wide- and small-angle X-ray scattering, optical birefringence, shrinkage measurements, and specific gravity. Shrinkage and birefringence results show a competition between two processes: chain re-coiling on the one hand and crystallization on the other hand. A consistent correlation among WAXS, SAXS, shrinkage, and birefringence results is demonstrated. SAXS data show a fibrillar morphology. On the basis of WAXS results, the crystallization is envisioned as a two stage process: first, the formation of defective fibrils, and then the formation of more perfect crystals. WAXS results also demonstrate a remelting phenomenon in samples which have experienced positive shrinking.