Copolymers of methyl methacrylate and fluoroalkyl methacrylates: Effects of fluoroalkyl groups on the thermal and optical properties of the copolymers

Fluoroalkyl methacrylates, 2,2,2‐trifluoroethyl methacrylate ( 1 ), hexafluoroisopropyl methacrylate ( 2 ), 1,1,1,3,3,3‐hexafluoro‐2‐methyl‐2‐propyl methacrylate ( 3 ), and perfluoro t‐butyl methacrylate ( 4 ) were synthesized. Homopolymers and copolymers of these fluoroalkyl methacrylates with methyl methacrylate (MMA) were prepared and characterized. With the exception of the copolymers of MMA and 2,2,2‐trifluoroethyl methacrylate ( 1 ), the glass transition temperatures (T_gs) of the copolymers were found to deviate positively from the Gordon‐Taylor equation. The positive deviation from the Gordon‐Taylor equation could be accounted for by the dipole–dipole intrachain interaction between the methyl ester group and the fluoroalkyl ester group of the monomer units. These T_g values of the copolymers were found to fit with the Schneider equation. The fitting parameters in the Schneider equation were calculated, and R² values, the coefficients of determination, were almost 1.0. The refractive indices of the copolymers, measured at 532, 633, and 839 nm wavelengths, were lower than that of PMMA and showed a linear relationship with monomer composition in the copolymers. 2 and MMA have a tendency to polymerize in an alternating uniform monomer composition, resulting in less light scattering. This result suggests that the copolymer prepared with an equal molar ratio of 2 and MMA may have useful properties with applications in optical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4748–4755, 2008     

An efficient synthesis of 3-aryl-2,3-dihydrothiophene-2-carboxamide derivatives by one-pot, four-component reaction

An efficient and convenient method for the preparation of 3-aryl-2,3-dihydr-othiophene-2-carboxamide derivatives in absolute ethyl alcohol by thiazolidine-2,4-dione, aromatic aldehyde, malononitrile and n-butylamine without using any other catalysts was reported. This methodology has the advantages of high yields, simple work-up procedure and mild reaction conditions.     

功能梯度材料结构热力耦合概率分析方法

基于自洽平均微观力学W-T(Wakashima-Tsukamoto)模型和拉丁超立方抽样,建立一种功能梯度平板热力耦合概率分析方法.以材料物理属性和空间分布的不确定性随机参数作为概率分析的输入,以热应力作为输出,基于本征正交分解POD(Proper Orthogonal Decomposition)对热应力的随机时间历...     

Highly porous 4,8-connected metal-organic frameworks: synthesis, characterization, and hydrogen uptake

A series of highly porous 4,8-connected isoreticular MOFs of the scu topology [Cu(4)(L(1))(H(2)O)(4)]·20DEF, [Cu(4)(L(2))(H(2)O)(4)]·16DMF·5H(2)O, and [Cu(4)(L(3))(H(2)O)(4)]·14DMF (L(1)-L(3) are (R)-1,1'-binaphthyl-derived octacarboxylate bridging ligands) were synthesized and characterized by single-crystal X-ray crystallography. Although the frameworks exhibit some distortion during the solvent removal process, the high-connectivity nature of the building blocks helps in stabilizing the frameworks, leading to high surface areas (S(BET) = 1189-2448 m(2)/g) and significant hydrogen uptake of up to 1.8 wt % (77 K, 1 atm).     

Chan-Lam-type S-arylation of thiols with boronic acids at room temperature

In this work, an efficient CuSO(4)-catalyzed S-arylation of thiols with aryl and heteroaryl boronic acids at room temperature is established. This catalytic system can tolerate a wide variety of thiols and arylboronic acids in the presence of only 5 mol % of CuSO(4) as the catalyst and inexpensive 1,10-phen·H(2)O as the ligand. Moreover, this catalytic system used environment-friendly solvent (EtOH) and oxidant (oxygen).     

Preparation and characterization of electrospun fibers based on poly(L-lactic acid)/cellulose acetate

PLLA/CA mixtures of different compositions were successfully electrospun to obtain composite nanofibrous membranes.The microstructures of the membrances changed from homogeneous to heterogeneous with the addition of CA, which was observed by FE-ESEM.The PLLA/CA fabric membranes were characterized by mechanical testing,DSC and contact angle measurements.The tensile stress of the composite fibrous membranes increased obviously with the increase of CA content.DSC results indicated that the CA component was the main factor for the changes of enthalpies in the composite fibers.Contact angle measurements showed the hydrophilicity of the electrospun nanofiber membranes was improved with the addition of CA.     

Synthesis and characterization of emulsifier-free trilayer core–shell polysilsesquioxane/polyacrylate/poly(fluorinated acrylate) hybrid latex particles

The trilayer core–shell polysilsesquioxane/polyacrylate/poly(fluorinated acrylate) (PSQ/PA/PFA) hybrid latex particles are successfully prepared, using functional PSQ latex particles with reactive methacryloxypropyl groups synthesized by the hydrolysis and polycondensation of (3-methacryloxypropyl)trimethoxysilane in the presence of a reactive emulsifier as seeds. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and dynamic light scattering (DLS) confirm that the resultant hybrid latex particles have evident trilayer core–shell structure and a narrow size distribution. The Fourier transform infrared (FTIR) spectra show that fluorinated acrylate monomers are effectively involved in the emulsion copolymerization and formed the fluorine-containing hybrid latex particles. XPS analysis of the obtained hybrid latex film reveals that the intensity of fluorine signal in the film–air interface is higher than that in the film–glass interface. In addition, compared with pure polyacrylate latex film, the obtained fluorine-containing hybrid film shows higher hydrophobicity and thermal stability, and lower surface free energy.     

布南色林与人血清白蛋白相互作用的光谱学研究

采用荧光光谱研究了模拟生理务件下抗精神病药布南色林与人血清白蛋白的相互作用,结果表明,布南色林对人血清白蛋白的内源性荧光具有猝灭作用且猝灭方式为静态猝灭.布南色林与人血清白蛋白形成了1∶1的复合物,结合常数K=1.80×104L/mol,且金属离子对结合反应具有较显著的影响.根据不同温度下的热力学函数确定了布南色林与人...