表面改性对VGCF分散性质的影响

针对气相生长碳纤维极易团聚及与树脂基体界面结合能力较差的难题,采用双氧水-浓硝酸二步法对VGCF进行表面改性处理。利用X射线衍射仪、热重分析仪、傅立叶红外光谱仪、紫外可见分光光度计等测试分析了改性前后VGCF的表面结构和在溶剂中的分散性,并以形状记忆聚氨酯为基体,采用溶液混合法制备了气相生长碳纤维/形状记忆聚氨酯的复合材料,测试了复合材料的力学性能。经过改性后,VGCF的石墨晶型结构几乎没有改变,VGCF表面的含氧官能团浓度得到较大提高,且其在有机溶剂中的分散性及分散稳定性也得到很大提高;在气相生长碳纤维/形状记忆聚氨酯的复合材料截面中,扫描电镜观察表明表面改性使得VGCF在基体中的分散性及与基体的界面结合能力都得到一定程度的提高;经二步法改性处理后的气相生长碳纤维比未处理气相生长碳纤维对复合材料的力学性能的增强效果更为明显。     

Pro-porous coordination polymers of the 1,4-bis((3,5-dimethyl-1H-pyrazol-4-yl)-methyl)benzene ligand with late transition metals

Solvothermal reactions of the flexible, pyrazole-based 1,4-bis((3,5-dimethyl-1H-pyrazol-4-yl)methyl)benzene ligand (H(2)BDMPX) with late transition metal ions allowed the isolation of the four coordination compounds M(x)(BDMPX) (x = 1 for M = Zn, 1; Co, 2; Cd, 3; x = 2 for M = Cu, 4). The investigation of the thermal behavior assessed the high thermal robustness of these materials, which are stable in air at least up to 300 °C, with the Cd(II) derivative starting to decompose only around 500 °C. As retrieved by ab initio X-ray powder diffraction, the isomorphous compounds 1-3 possess a dense 3-D network featuring rhombic motifs hinged about rigid and parallel chains of tetrahedral MN(4) chromophores. As demonstrated by thermodiffractometric measurements, temperature increase triggers framework flexibility. The latter is at work also when N(2) adsorption is assayed at 77 K: 1 and 2 show permanent porosity, with BET and Langmuir specific surface areas of 515, 667 m(2)/g and 209, 384 m(2)/g, respectively. 1 and 2 thus represent an intriguing example of "porosity without pores", their pro-porous nature being explained in terms of the flexibility of the rhombic motifs, stimulated by the gas probe and facilitated by the nature of the ligand.     

Solubilization of various fluorocarbons in a fluorinated surfactant/water system: relation with the design of porous materials

We have investigated the phase behavior of the R(F)(7)(EO)(8) surfactant in water as well as the effect of the solubilization of various fluorocarbons in this system. Results show that the cloud point (CP) curve is shifted to high temperatures upon addition of fluorocarbons, following the sequence 1-bromo-perfluorooctane (PFOB) < perfluorodecalin (PFD) < perfluorooctane (PFO). The values of the phase inversion temperature (PIT) associated with these systems increase in the same order: PFOB approximately 65 degrees C, PFD approximately 82 degrees C, and PFO > 90 degrees C. Starting from these systems, we have prepared mesoporous and hierarchical porous materials. The formation of the ordered mesoporous materials has been related to the CP curve. Indeed, our results show that mesoporous materials with a high degree of ordering are obtained from systems whose CP curve is shifted toward high temperatures. We have also correlated the formation of the hierarchical porous silica to the PIT. It appears that the design of macro-mesoporous materials is favored with systems that exhibit a high value of the PIT.     

Novel coordination frameworks incorporating the 4,4'-bipyrazolyl ditopic ligand

The reaction of the rigid spacer 4,4'-bipyrazole (H(2)BPZ) with late transition metals, either following conventional routes or under solvothermal conditions, afforded the coordination polymers [M(BPZ)]·Solv (M = Zn, 1; Co, 2; Cd, 3; Hg, 4; Cu, 5; Ni, 6; Pd, 7; Solv = DMF, 3; MeCN, 5 and 6; H(2)O, 7), [Cu(H(2)BPZ)(2)(NO(3))(2)] (8), and [Cd(H(2)BPZ)(CH(3)COO)(2)] (9). State-of-the-art laboratory powder diffraction methods allowed to disclose the isomorphous character of 1 and 2, as well as of 5 and 6, which feature 3D porous networks containing 1D channels of square and rhombic shape, respectively. 3, crystallizing in the relatively rare P6(1)22 space group, consists of homochiral helices of octahedral Cd(II) ions, packing in bundles mutually linked by "radial", nonplanar BPZ ligands. Finally, the dense species 8 and 9 contain parallel 2D layers of square and rectangular meshes, respectively. Thermogravimetric analyses witnessed the relevant thermal robustness of all the [M(BPZ)] materials [except the mercury(II) derivative], which are stable in air at least up to 300 °C, with the zinc(II) derivative decomposing only around 450 °C. Variable-temperature powder diffraction experiments highlighted the permanent porosity of 1-3, 5, and 6, retained along consecutive temperature cycles in all cases but 3. When probed with N(2) at 77 K, 1-3 and 5-7 showed Brunauer-Emmett-Teller and Langmuir specific surface areas in the ranges 314(2)-993(11) and 509(16)-1105(1) m(2)/g, respectively.     

Alcohols solubilization in a nonionic fluorinated surfactant based system: effects on the characteristics of mesoporous silica

In this study, we have used hydrogenated alcohols with different chain lengths and one fluorinated alcohol as additives to determine their effect on the characteristics of mesoporous materials prepared from fluorinated micelles.     

Synthesis and Crystal Structure of a Novel Tetravanadate Modified by Chiral Racemoid Zirconium Complex

1 INTRODUCTION Polyoxometalate anions are a broad class of dis- crete metal-oxide compounds MxOyn–, which are of both fundamental and practical interest in a range of areas, including catalysis, biochemistry, medicine and solid state devices[1~6]. Recently, the structural chemistry of vanadium oxides in combination with secondary metal-ligand cations has attracted much attention[7~17]. These hybrid materials manifest the structural influences both of coordination preferen- ces of the sec…     

Isolation and Crystal Structure of 1',4'-Trans-diol of Abscisic Acid

1 INTRODUCTION It has been reported that botrytis cinerea, a plant pathogenic fungus, can produce abscisic acid ((2- cis,4-trans)-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2- cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid 1)[1] and 1?,4?-trans-diol of abscisic acid 2 that is a pre- cursor of 1[2]. Abscisic acid is an important plant hormone that can inhibit the germination of seeds[3]. Meanwhile, the derivatives of 2, 1?,4?-trans-diol of abscisic acid ester 3 and 4?-methoxy derivative 4, are oil…     

Synthesis and Crystal Structure of 1,4,Bis-（benztriazol-1-ylmethyl）-2,3,5,6-tetramethylbenzene

1 INTRODUCTION Crystal engineering of supramolecular arrays hasbeen one of the most important areas of researchwith wide implications for the rational design offunctional materials[1]. Two major directions[2] havebeen actively pursued: the construction of organicnetworks consolidated by directional non-covalentinteractions[3] and that of coordination polymers sus-tained by coordinated covalent bonds[4, . One of the 5]most remarkable developm…     

Synthesis, Crystal Structure and Optical Properties of a New Nd(III) Nitronyl Nitroxide Complex [Nd(NIT2Py)_2(NO_3)_3]

1 INTRODUCTION Nitronyl nitroxides, independently or in combina- tion with metal ions, have been one of the most widely studied systems in molecular magnetism for understanding the radical-radical or metal-radical interactions as well as for synthesizing organic ferro- magnets and metal-radical magnetic materials[1～3]. Meanwhile, investigations on molecular coordina- tion compounds of lanthanide ions have also attrac- ted great attention due to their luminescence[4, 5] or magnetic propert…     

Syntheses of Binuclear Copper(I) Complexes Containing Benzimidazole

1 INTRODUCTION Procedures to synthesize copper(I) complexes are of great interest due to the diversity of products resulting from almost the same methodology. It has been long known that four-electron-donordipho- sphine compounds Ph2P(CH2)nPPh2 are excellent bi- dentate ligands[1, 2]. The chelating tendency of bis- (diphenylphosphino) methane is one of the dipho- sphine ligands most suitable to lock two metal atoms together in close proximity[3]. Many examples of bi- or polynuclear com…