X-射线法测定间规-1,2聚丁二烯结晶度

根据X-射线衍射强度理论和高聚物两相模型概念,对沿用的作图法计算结晶度的公式进行了修正,求出间规-1,2聚丁二烯(St-1,2 PB)四个主要衍射峰的校正因子,从而导出了St-1,2 PB的结晶度计算公式。用所给公式计算的结晶度数值与用密度梯度法测得的结晶度数值相比,结果是满意的。     

X-射线衍射法测定尼龙1010结晶度

根据X-射线散射强度理论,使用图解多重峰方法对尼龙1010三个结晶峰及非晶峰的衍射强度进行校正,首次导出了尼龙1010结晶度计算公式,所得结果与密度及量热测定结果具有很好可比性。     

用X-射线衍射法测定聚对苯二甲酸乙二醇酯/聚对苯二甲酸丁二醇酯共混体系的结晶度

结晶度是表征聚合物性质的重要参数,它对聚合物的物理和机械性能有很大影响,在测定聚合物的结晶度的各种方法中,X-射线衍射法的意义明确且应用最为广泛。然而,用X-射线衍射法测定聚合物结晶度绝大部分只限于单组份体系,用于共混体系的报道尚不     

乙丙嵌段共聚物的X-射线衍射研究

用大角X-射线衍射(WAXD)方法对按嵌段聚合程序合成的聚丙烯(PP)和乙丙共聚物(EPR)的嵌段共聚物PP-EPR和PP-EPR-PP,以及相应的混合物进行对比研究.乙丙共聚物及其共混物均发现在2θ=20°处存在由EPR中PP链段引起的γ-晶型衍射峰.通过诠释X-射线衍射图,计算结晶度,微晶尺寸和晶格参数等表明,用δ-TiCl_3-Et_2AlCl催化剂获得了嵌段共聚物结构.     

聚合物材料结晶度（上）

本文介绍了结晶度概念及IUPAC高分子专业委员会最近有关结晶度各述语的一些规定,几种常用的结晶度测定方法,如X射线衍射、量热法、密度测量、红外光谱法等,对X射线衍射方法作了重点叙述.     

芦丁和槲皮素的几种快速鉴定方法

采用热分析(TA)、红外光谱法(FTIR)和X-射线衍射技术(XRD)对以槐米为原料制备的芦丁和槲皮素提取物进行了测定,通过分析二者谱图特征探讨快速鉴别这两种黄酮类化合物的方法。实验结果表明,芦丁的微商热重(DTG)曲线于278℃出现明显的热分解失重峰,差示扫描量热(DSC)曲线未出现明显相变峰;槲皮素的DTG曲线于349℃出现明显的失重峰,DSC曲线分别于323和361℃出现一个吸热峰和一个放热峰。红外谱图显示,3386 cm-1羟基伸缩振动吸收峰,1656 cm-1羰基伸缩振动吸收峰以及2931、1064、881 cm-1糖基的特征吸收峰可作为区分芦丁和槲皮素的标准峰。芦丁的X-射线衍射图谱呈多峰重叠的弥散峰,结晶度低;而槲皮素峰形明锐,结晶度高。因此,热分析、红外光谱及X-射线衍射技术可用于鉴别芦丁和槲皮素,相应谱图可作为它们各自的特征指纹图谱。     

高速纺PET纤维中介态的X-射线衍射研究

研究用X-射线衍射法分析纤维结构中介态的变化。直接以X-射线衍射法测量并计算高速纺PET纤维非晶区的取向因子及中介态的相对含量,提出利用晶区和非晶区取向因子的区别来分离非晶态衍射曲线的方法,建立了X-射线衍射法计算非晶区取向因子的公式及中介态百分含量的方法。     

由乙烯高效催化聚合而得的超高分子量聚乙烯的研究

本工作系研究以高效催化聚合获得的超高分子量聚乙烯的结构和性能。用扫描电子显微镜观察了高效催化剂及初生聚乙烯的形态。透射电子显微镜观察了初生聚乙烯粉未,发现毛遂边缘的超分子原纤维状织态结构。用偏光显微镜观察了不同分子量聚乙烯粉末的熔融和冷却结晶过程,生成的球晶随分子量增大而增大。用X-射线衍射、差热分析、倒换气相色谱测定了初生聚乙烯的结晶度随分子量而增大;用X-射线衍射、差热分析及密度梯度法测定经退火或热压制的聚乙烯样品的结晶度均随分子量增大而下降。X-射线衍射测定其晶粒尺寸亦随分子量增大而减小。差热分析和倒换气相色谱测定超高分子量聚乙烯粉末的结晶熔点温度(T_m)要比普通分子量聚乙烯高8-12℃。不同分子量聚乙烯的热形变曲线表明,超高分子量聚乙烯在熔融温度后出现明显的橡胶态。此外,还用差热与热重分析研究了超高分子量聚乙烯的热老化行为。测定了超高分子量聚乙烯的优异抗冲强度和沙浆磨耗量。并用扫描电镜对比观察了常规分子量和超高分子量聚乙烯试样的冲击断面的织态结构。     

非晶体的X-射线衍射图

David Sayre及其合作者首次得到了非晶样品的衍射图。他们的革命性的功绩在于能得到不可能结晶的大量物质的衍射图 ,这些非晶体可以是从细胞到个别蛋白质分子的任何材料 ,并且可得到超高分辨率衍射图。他们首次得到的是一批微小的金粉的衍射图 ,分辩率为 75nm,虽然这比不上晶体样品 X-射线衍射的分辩率 ,但已经比最好的光学显微镜的分辩率高。要从单个分子获得足够多的衍射数据 ,需要比现在所用的 X-射线亮几十亿倍的新的 X-射线。非晶体的X-射线衍射图@万家义     

利用X射线衍射法测定固相氯化法氯化聚乙烯的结晶度

本实验根据X射线衍射强度理论和聚合物两相模型概念,采用逐级近似的方法,利用X射线衍射技术,测得了固相氯化法CPR的结晶度。结果表明,当Cl%≤12.0%时,随着氯含量的增加,固相氯化法CPE的结晶度逐渐减小。     

THE DEGREE OF CRYSTALLINITY OF MULTICOMPONENT POLYMERS BY WAXD

Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of the multicomponent polymers were derived in terms of WAXDtheory and improved graphic multipeak resolution methods. The results calculated aresatisfactory in comparison with the density measurement.     

Numerical analysis of complex dielectric mixture formulae

As a continuation of our earlier work (Ref. [9]) the complex (frequency dependent) dielectric behaviour of some mixture formulae are studied numerically. These include matrix-inclusion type formulae (as the Wagner-Sillars or the Bruggeman-Boyle equations), mean-field statistical mixture formulae (as the Böttcher-Hsu equation) and symmetrical integral formulae (as the Looyenga equation). The frequency dependent dielectric properties are first calculated for a model system at various particle shapes, field orientations and volume fractions. After this, the validity of these equations is checked on typical sets of experimental data. For low loss powders, the Böttcher and Looyenga equations are suggested; for emulsions, suspensions and filled polymers, the matrix-inclusion type formulae give acceptable results in most cases, while for metal-insulator composites mean-field statistical mixture formulae have to be used, as they are capable of describing the percolation phenomenon.     

Charge carrier transport in heterogeneous conducting polymer materials

The similarities of conductivity mechanisms of composites and nanocomposites and doped conjugated polymers that are also characteristic of specific heterogeneity are discussed. It is shown that the formulae developed to account for internal heterogeneity of conductive polymers can be applied also for polymer composites in spite of low overall content of the conductive phase. For fully organic nanocomposites (reticulate doped polymers) showing metal-like conductivity and a crossover temperature effective contribution of metallic phase is estimated. Examples of different properties of nanoparticles forming conducting networks as compared with the bulk crystals are discussed.     

Polymers from a levopimaric acid–acrylic acid Diels–Alder adduct: Synthesis and characterization

The Diels–Alder adduct of levopimaric acid with acrylic acid was efficiently prepared from resin acids. When the adduct was subjected to a dehydrodecarboxylation reaction, a ketone diacid derivative was obtained. New ketone type linear polymers were synthesized by the advanced dehyrodecarboxylation, a nonconventional polycondensation reaction, of both the above in presence of sulfonic catalysts. The polyketones turned out to be excellent tackifiers in adhesive formulae. The ketone polymers were condensed with diamines to give crosslinked polyazomethines. The structures of the monomers and polymers were established by means of elemental analysis, IR and NMR spectroscopy, and molecular weight determinations. Both the polyketones and polyazomethines were low‐molecular‐weight polymers, soluble in some polar and nonpolar solvents. The thermal behavior of the monomers and polymers was evaluated by thermogravimetric analysis. The thermal studies showed that the polymers were substances with good thermal stability, except the polyazomethine synthesized by the condensation of polyketone with an aromatic diamine, which appeared to be a substance with high thermal stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5979–5990, 2007     

INVERSION OF MULTILAYERED VARIABLE DENSITY MODELS AND STUDY OF CRUSTAL AND UPPER MANTLE STRUCTURE

This paper presents a direct gravity inverse method of multilayered variable density models, and gives gravity forward formulae under various conditions of density-depth functions such as the constant, exponential, linear, sine and cosine, cubic spline, and Fourier progression. The testing of theoretical models and the analysis of real examples have been made for the cubic spline function and have proved that the method is effective. Other formulae can be applied under corresponding conditions by means of optimization or other methods.     

Synthesis and Study of Some New Co(II) Polyphosphinates Determination of the Kinetic Parameters for the Thermal Decomposition Reactions

This paper reports the synthesis and study of some Co(II) coordination polymers with the following acids as ligands: 2,8-dimethylphenoxyphosphinic, diphenyloxyphosphinacetic, diphenylthiophosphinacetic and dihexylphosphinic acids. The study was performed by means of chemical analysis, gel chromatography, IR spectroscopy, ESR, X-ray diffraction, thermogravimetry and electric resistance measurements. The experimental results were used to propose the structural formulae of these compounds and to calculate the kinetic parameters of the thermal decomposition reactions. This revised version was published online in July 2006 with corrections to the Cover Date.     

一类新的刚性链侧链型液晶高分子的合成

以自由基聚合方法，合成了一系列含有三个苯环通过酯键相联的液晶性单体及其聚合物．在这类新的液晶高分子中，刚性液晶基元不通过柔性间隔基而直接竖挂在聚甲基丙烯酸酯大分子主链上．这些高分子有很高的玻璃化转变温度，表明其分子链刚性较大，因而代表了一类新的刚性链侧链型液晶高分子．它们的液晶行为用ＤＳＣ、偏光显微镜和Ｘ－光衍射进行了表征．发现所有单体和聚合物均为向列型热致性液晶．     

偶氮苯侧链结构对聚丙烯酸酯三阶非线性光学性能影响

设计合成了一系列含偶氮苯非线性生色团的丙烯酸酯,并采用溶液聚合法合成了功能化的聚丙烯酸酯,利用FTIR、NMR、UV等对化合物的结构进行了表征,证实得到了指定结构的化合物.利用Z扫描技术对合成的聚丙烯酸酯的非线性光学性能进行了研究,通过对聚合物的非线性光学吸收拟合,计算得到非线性吸收系数β和三阶非线性系数χ(3),并探讨了取代基生色团分子结构与高分子三阶非线性光学性能的关系,结果显示增大侧链生色团π电子离域长度或强DπA(推拉基团)结构均可有效提高聚合物的三阶非线性光学性能.     

芳香族二胺聚合物的合成及其性能

<正> 在导电性有机固体研究领域中导电聚合物的研究占有不可忽视的地位,特别是70年代以来聚苯胺及其掺杂物导电性的发现更加引起了人们对有机导体的极大兴趣,人们从聚合物的合成到性能的表征展开了广泛研究,主要工作集中在聚苯胺、聚吡咯等各种合成方法及电性能表征方面。有关芳香族多胺聚合物的合成及表征却很少见文献报道,Tsuchida等人曾报道了在铁盐与含氮化合物形成的络合物存在下对苯二胺及对苯二酚氧化聚合得到具有顺磁性、电导率为10~(-10)Scm~(-1)的聚合物。80年代末期Torrance报道了在较缓和的条件下均苯三胺聚合可以得到铁磁性聚合物,本文对三种苯二胺聚合物的合成及其电性能、热稳定性能等做了初步研究。     

一系列新的席夫碱型液晶高分子冠醚的合成与表征

以 4,4′ (α,ω 烷亚甲基二酰氧 )二苯甲醛和二氨基二苯并 1 5 冠 5为单体 ,采用溶液缩聚方法 ,合成了一类新的席夫碱型液晶高分子冠醚 .一种单体采用脂族二酰氯和对羟基苯甲醛反应制备 ,另一种新的单体采用二硝基二苯并 1 5 冠 5 ,在钯 碳催化剂存在下 ,水合肼还原制备 .合成的二硝基和二氨基 二苯并 1 5 冠 5 ,未能从IR和1 H NMR谱图上区分它们的几何异构体 .聚合物的分子量不高 ,Mn 在 1 0 1 0 0～ 1 3 0 0 0之间 .单体的结构通过元素分析、IR、1 H NMR和MS等方法确证 .聚合物的性质采用GPC、DSC、TG和POM等方法进行了研究 .发现所有的聚合物加热到各自的熔融温度 (Tm)以上都能形成液晶态 ,在液晶态可以观察到向列相的丝状织构和纹影织构 .聚合物的玻璃化转变温度 (Tg)、熔融温度和各向同性温度 (Ti)随聚合物分子中柔性间隔基的变化而变化 ,它们有较高的清亮点温度和宽的液晶态温度范围 .WAXD的研究进一步证实了聚合物的液晶性