Preparation and structural characterization of nanocrystalline poly(vinyl chloride)

This article describes the development of novel nanocrystalline poly(vinyl chloride) (PVC) for potential applications in PVC processes and reports improvements in the mechanical properties and thermal resistance. Before the preparation of nanocrystalline PVC via jet milling, PVC was spray‐treated and heat‐treated to improve its crystallinity. The pulverization and degradation, morphology, crystalline structure, and melting‐point changes of postmodified PVC during jet milling and the relationship between the distributions of the particle size and processing temperature were investigated. X‐ray analysis and density testing indicated increased density and improved crystallinity. The crystalline region of nanocrystalline PVC was less than 80 nm, with a particle size distribution of 5–20 μm and a melting point of less than 128°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 563–569, 2004     

Synthesis and structural characterization of two complex tantalum(V) siloxides

The reaction of tantalum(V) ethoxide, Ta(OEt)₅, with 1 equiv. of 1,1,3,3-tetraphenyl-disiloxane-1,3-diol, (HO)SiPh₂OSi-Ph₂(OH) (1), afforded the dinuclear tantalum(V) disiloxanediolate complex [{μ-(Ph₂OSiO)₂O}Ta(OEt)₂(μ-OEt)]₂ (3). Similarly, Ta(OEt)₅ reacted with the incompletely condensed silsesquioxane precursor Cy₇Si₇O₉(OH)₃ (2, Cy = cyclohexyl) in a 1:1 molar ratio to afford the dinuclear tantalasilsesquioxane derivative [Cy₇Si₇O₁₂Ta(OEt)(μ-OEt)]₂ (4) in 80% yield. Both new complexes were structurally characterized by single-crystal X-ray diffraction studies.     

New molybdenum(VI) complex with ONS-donor thiosemicarbazone ligand: Preparation,structural characterization,and catalytic applications in olefin epoxidation

New dioxomolybdenum(VI) complex was prepared by reacting 1-(2,4-dihydroxybenzylidene)-N-methyl-N-phenylthiosemicarbazone (H₂L) as ligand and [MoO₂(acac)₂] in acetonitrile solution. The doubly deprotonated ligand is coordinated to molybdenum through sulfur atom, hydrazinic nitrogen atom and phenolic oxygen atom. The resulting complex with the formula [MoO₂L(CH₃CN)] which contains an acetonitrile molecule in sixth site of coordination, was characterized by elemental analyses, ¹H NMR, IR and electronic spectroscopic studies and single crystal X-ray diffraction analysis. This complex was tested as a catalyst for the homogeneous epoxidation of olefins using tert-butyl hydrogen peroxide (TBHP) as an oxidant. The catalyst shows efficient reactivity in the olefins epoxidation reactions giving high yield and selectivity under atmospheric conditions, in most cases.     

新型阴离子水煤浆分散剂的制备与表征

以甲基丙烯酸(MAA)和丙烯磺酸钠(SAS)为原料,(NH4)2S2O8/NaHSO3氧化还原体系作为引发剂,NaH-SO3同时为链转移剂,采用水溶液自由基聚合反应,制得了甲基丙烯酸-丙烯磺酸钠共聚物(PMS)分散剂,通过TGA-DSC、GPC及IR等手段对聚合物的结构、热稳定性以及相对分子质量及其分布进行了表征和分析。并考察了PMS的合成条件及用量对水煤浆分散效果的影响。实验表明,PMS最佳合成条件为:甲基丙烯酸和丙烯磺酸钠的单体摩尔比为0.65∶0.35,引发剂用量占单体的质量分数8%,其中(NH4)2S2O8∶NHSO3=4∶1.67,反应温度为75℃,其用量为0.5%时,水煤浆的分散性能最佳。     

Preparation and structural characterisation of a Cd(II) complex with unusual geometry

Reaction of Cd(NO₃)₂ · 4H₂O with ethyl-2-pyridinecarboxylate yields [Cd(NO₃)₂(C₅H₄NCOOEt)₂]. Elemental analyses, conductivity measurements, infrared, ¹H and ¹³C{¹H} NMR spectroscopies and single-crystal X-ray diffraction enabled us to characterise this complex. The crystal structure consists of monomeric units in which the cadmium atom is eight-coordinated.     

Preparation and characterization of anion exchangers from petroleum asphaltites

The chloromethylation reaction of an asphaltite and styrene graft copolymer followed by the amination of the chloromethylated products was optimized. New strongly basic anion exchangers with an exchange capacity of 2.5 mg-equiv/g and a mechanical strength of 93% were prepared.     

Synthesis and X-ray structural characterization of square-pyramidal copper(II) complex with aminoguanidine derivative

Aminoguanidine and its derivatives have shown antiglycation activity and are effective antioxidants. Complexes with ligands derived from aminoguanidine are relevant to both medicinal and bioinorganic chemistry. In this article, we describe the synthesis and characterization of a new mononuclear complex of copper(II) with a chelating ligand derived from aminoguanidine. Single crystals of the resulting complex were obtained by recrystallization from isopropanol. The molecular structure of the complex was obtained by X-ray diffraction which shows a distorted square pyramidal geometry, where copper(II) is coordinated to four nitrogen atoms (base of the pyramid) and to one chlorine atom (pyramid peak). The spectroscopic behavior (FT-IR and UV–vis) of both the complex and the ligand were examined.     

TOSPA复合物的制备及其结构表征

4,1′,6′-三氯-2,3,6,3′,4′-五乙酰基蔗糖(TOSPA)是全基团法制备三氯蔗糖的关键中间体,采用苄基三乙基氯化胺(TEBA)为催化剂,氯化亚砜为氯化剂合成了TOSPA。研究结果表明:氯化亚砜用量、反应温度对收率有较大影响,当氯化亚砜过量50%,90℃下反应6h,收率达到90%。实验中制备了TOSPA与甲苯的复合物,并经X射线单晶衍射、核磁、红外、元素分析进行了验证。利用TOSPA与甲苯复合物的物理特性,分离纯化得到了高纯度的TOSPA,具有工业化应用的前景。     

Synthesis, structural characterization, and magnetism of a butterfly-shaped hexanuclear Ni(II) complex

A new butterfly-shaped hexanuclear complex [Ni₆L₄H₂O(C₅H₅N)₄] · 2DMF (L = anion of N-(3-t-butylbenzoyl)-5-bromosalicylhydrazide) has been synthesized and characterized structurally and magnetically, which contains two trinuclear [Ni₃L₂(py)₂] subunits bridged by two μ₂-O(carbonyl) and one μ₂-O(H₂O) groups. It exhibits obvious ferromagnetic interaction owe to the central Ni(II) dimer with octahedral geometries.     

掺杂双核咪唑离子液体阴离子膜的制备与表征

以双核N-十二烷基咪唑与1,4-二溴丁烷为原料,异丙醇为溶剂,通过两步法合成双核咪唑离子液体。以壳聚糖为基料,掺杂双核咪唑离子液体,用戊二醛(GA)交联,制备一系列交联型阴离子交换膜。考察了离子液体的加入量和交联剂的用量对膜含水率、机械强度、离子交换量(IEC)、电导率等各项性能的影响。结果表明,交联剂和离子液体加入量的增加可有效降低膜的含水率,增加离子交换量和导电率,其中交联剂对机械性提高效果明显,交联剂和离子液体的加入量为6%和5%时,取得合适的含水率和溶胀度,分别为106%和131%。在温度70℃时,复合膜的电导率最高可达0.063 5 S/cm。     

Silver(I) cis-diphenylphosphinoethylene complexes: Spectroscopic and structural characterization

Adducts of the diphosphine cis-Ph₂P(CHCH)PPh₂ (L) with AgX (X = NO₃, BF₄, ClO₄ or CF₃SO₃) have been synthesized and characterized both in solution (¹H, ³¹P NMR) and in the solid state (IR, single crystal X-ray structure analysis). The topologies of the structures in the solid state were found to depend on the nature of the counter-ion X. The adduct AgNO₃:L (2:1)₂ is tetranuclear, derivative of the chair form, the bidentate ligands bridging peripheral silver centers, the nitrates being coordinated through two oxygen atoms, the first O,O′-bridging the second bridging bidentate.     

Preparation and characterization of poly(p-phenylenediamine-co-xylidine)

p-Phenylenediamine (PPDA) homopolymer and its copolymers with 2,3-xylidine (XY) were synthesized by oxidative polymerization using potassium persulfate as an oxidant in HCl medium at room temperature. The yield, intrinsic viscosity, and solubility of the polymers were significantly dependent on the monomer ratio. The resulting polymers were characterized by Fourier transform IR spectroscopy, ¹H-NMR spectroscopy, wide-angle X-ray diffraction, and thermogravimetry methods. The results showed that the number-average degree of polymerization of the PPDA homopolymer was 33 and the actual content of XY units in the copolymer was slightly higher than the feed XY unit content. The polymers were substantially amorphous and showed the strongest diffraction at a Bragg angle of 3°. The polymers exhibited a thermal decomposition temperature higher than 436°C, the maximum weight-loss rate was slower than 4%/min, and the char yield was larger than 24 wt % at 600°C in nitrogen. The activation energy of thermal decomposition for the polymers increased from 19 to 25 kJ/mol with increasing XY unit contents from 0 to 10 mol %. The polymers showed higher thermostability but lower activation energy of decomposition in nitrogen than in air. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3107–3116, 2001     

Preparation of a new type of half-sandwich (alkoxylalkylcyclopentadienyl)titanium trichloride complex and X-ray structural characterization of (CH3OCH2CH(CH3)C5H4)TiCl3

New substituted alkoxylalkylcyclopentadienyl titanium trichloride complexes, CH₃OCH₂CH(CH₃)C₅H₄TiCl₃ (3), CH₃OCH(CH₃)CH₂C₅H₄TiCl₃ (4) and CH₃OCH₂CH₂CH₂C₅H₄TiCl₃ (5) have been synthesized and 3 has been studied by X-ray diffraction. The crystal structure of 3 shows that there is an intramolecular coordination between the ethereal oxygen atom in the side chain on the Cp ring and the titanium atom with an average Ti–O bond length of 2.24 Å. Due to steric limitation around the coordination sphere of titanium, the oxygen atoms in the side chain in complexes 4 and 5 do not coordinate with the central metals.     

聚吡咯/凹凸棒土纳米复合材料的制备及结构表征

以十二烷基磺酸钠为掺杂剂,FeCl3·6H2O为氧化剂,引发吡咯单体（Py）发生化学氧化聚合,制备出聚吡咯/凹凸棒土纳米复合材料（PPy/ATP）,并通过XRD、TG-DTA、FTIR和TEM等技术手段对所得的复合材料进行了表征。体积电阻率测量表明,随着Py用量的增大,纳米复合材料的体积电阻率逐渐变小,当Py/ATP的质量比≥0.25时体积电阻率变化不大。XRD和TEM显示,聚吡咯以非晶态形式包覆在凹凸棒土单晶的表面,形成核-壳棒状纳米结构,包覆层厚度约为2 nm。TG-DTA表明凹凸棒土纳米复合材料的耐热性能与纯聚吡咯相比明显提高。FTIR表明纳米复合材料中聚吡咯与凹凸棒土之间存在物理作用。     

Influence of selected cation and anion species on the adsorption of mercury (II) by montmorillonite

The influence of Cl⁻, NO₃⁻, ClO₄⁻, Na⁺, and Ca²⁺ on the kinetics of the Hg adsorption by montmorillonite was studied. The data indicate that the Hg adsorption process in different salt solutions obeyed multiple first order kinetics. In the absence of salts, the Hg adsorption in the fast process was 1.6, 2.0, 2.0, 4.6, and 4.6 times faster than that in the presence of NaClO₄, NaNO₃, Ca(NO₃)₂, NaCl, and CaCl₂, respectively. Similarly, after the initial rapid adsorption, the system in the presence of the strong complexing ligand, Cl⁻, had a slower adsorption rate than the systems in the absence of salts or in the presence of weaker ligands, NO₃⁻ and ClO₄⁻. However, the bulk of the Hg adsorption by montmorillonite took place in the initial rapid adsorption process. The magnitude of the reduction in the rate of the Hg adsorption was evidently dependent upon the ability of the ligands to complex with Hg. No significant differences between Na⁺ and Ca²⁺ in their ability to suppress the Hg adsorption were observed. When the Cl/Hg and ClO₄/Hg molar ratios were higher than 50 and 500, respectively, their suppressing effects on the adsorption of Hg by montmorillonite were evident.     

Preparation,characterization and antioxidant activity of acetylated garlic polysaccharide,and garlic polysaccharide-Zn (II) complex

Garlic polysaccharide (PS) was extracted from garlic by hot-water extraction. Acetylated garlic polysaccharide (AcPS) and garlic polysaccharide-zinc complex (ZnPS) were synthesized. The results of Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy analysis showed that the modifications were successful. The antioxidant activities of PS, AcPS, and ZnPS were further investigated in vitro, including scavenging superoxide anion and hydroxyl radicals, antilipid peroxidation capacity, and reducing power. The results showed that the scavenging abilities of AcPS and ZnPS on hydroxyl radical (The IC₅₀ of PS, AcPS, and ZnPS were 2.86, 1.62 and, 1.49 mg/ml, respectively,) and superoxide anion radical (The scavenging rate of PS, AcPS, and ZnPS were 1.5% and 1.8%, and 2.3%, respectively, when concentration was at 1.0 mg/ml.) were stronger than that of PS, and the inhibitory effect of AcPS on lipid peroxidation was significantly stronger than that of PS (The IC₅₀ of PS and AcPS were 1.05 and 0.53 mg/ml, respectively.). It indicated that the acetylation was a favorable way to enhance the antioxidant activity of garlic PS; ZnPS complex could be applied as potential candidate for antioxidant and Zn supplement.     

N-十二烷基二亚甲基膦酸钠的制备及表征

基于Mannich反应,以十二胺、甲醛和亚磷酸为原料,盐酸为催化剂制备出N-十二烷基二亚甲基膦酸,产率达95.75%。使用氢氧化钠与N-十二烷基二亚甲基膦酸反应,制备出了目的产物N-十二烷基二亚甲基膦酸钠。通过对产物进行31PNMR,1HNMR和元素分析,证明所制备产物为目的产物,且较为纯净。对产物溶液的表面张力进行了测定,发现其表面张力随着p H的变化呈现有规律的变化,且变化趋势与其结构信息一致。     

聚联苯四甲酰亚胺合成与表征

采用5,6-二苯基-1,2,3,4-联苯四甲酸二酐和一系列芳香族二胺为原料,经溶液亲核取代反应,聚合得到取代聚联苯四甲酰亚胺均聚物和共聚物。采用红外和核磁共振等分析方法进行了结构表征,研究在不同溶剂中的溶解性能,以及通过差示扫描量热法和热失重分析研究了热性能。     

Preparation and characterization of poly(ethylene-graft-ethylene oxide)

Graft copolymers containing poly(ethylene oxide) side chains attached to a polyethylene backbone were prepared by coupling of poly(ethylene-co-acrylic acid) (PEAA) and poly(ethylene oxide) monomethyl ethers (MPEO) by esterification in o-xylene at 140°C. The MPEO side chains had molecular weights of 750 to 5000. The chemical composition of the graft copolymers was analyzed by NMR and FT–IR spectroscopy. The weight fraction of the MPEO grafts in the graft copolymers was found to be around 0.4. The graft copolymers exhibited a phase-separated morphology with the backbones and the MPEO phase had a melting temperature 8–25°C lower than the corresponding MPEO homopolymers, as determined by DSC. The melting point of the crystalline phase formed by the PEAA main chains was close to that of the pure PEAA. Crystallinity was also confirmed by x-ray diffraction. © 1996 John Wiley & Sons, Inc.