环氧树脂的紫外光引发阳离子／自由基固化

研究了两类阳离子引发剂复合苯基硫钅翁盐和芳茂铁盐的紫外光引发活性以及它们分别与自由基引发剂的复合体系的增强光引发活性，并讨论了强氧化剂异丙苯过氧化氢对于芳茂铁盐引发效率的促进作用以及适量多元醇对于提高阳离子固化体系交联度所起的作用     

From monotonic to oscillatory decay of correlations: Analytical approximation for the two-dimensional,one-component plasma

An approximate evaluation of the pair distribution and the structure factor is performed analytically for the two-dimensional, one-component plasma at any value of the coupling constant. The approximate distribution remains positive and satisfies three sum rules, including the compressibility one. When 0 or 2, exact results are found. At=2 the transition from monotonie (<2) to oscillatory (>2) decay of correlations takes place. Comparison with the Monte Carlo simulations shows good agreement for 0<<4.     

长条形空间反射镜无热化胶层的优化设计

为了实现尺寸为1 200 mm×484 mm的大长宽比长条形空间反射镜的无热装配,减小反射镜面形精度受热应力的影响,本文对环氧胶(GHJ-01(Z))胶层厚度对反射镜面形的影响及胶层在静、动力学载荷下的应力进行了研究。首先,介绍了现有的几种基于胡克定律推导的无热粘结厚度方程及其假设条件,并推导了带有锥度的背部盲孔反射镜无热粘结胶层厚度的方程,得出无热粘结胶层厚度曲线;然后,建立了6种不同胶层厚度的反射镜组件模型并进行了分析与比较。通过分析,在+5℃温升工况下,反射镜胶层厚度为0.07 mm时具有最好的面形精度,其RMS值0.0178λ,其检测方向在自重作用下的面形精度RMS值为0.0173λ,一阶频率为220.17 Hz;最后对胶层无热化设计后的反射镜组件进行了振动试验和粘结剂剪切强度试验,分析与试验表明:反射镜组件一阶频率为216.4 Hz,与有限元分析结果相对误差为1.71%;满足动静态刚度要求;同时,在动力学载荷下该厚度胶层的应力均小于其固化后的抗剪强度,安全裕度为2.46;各项指标满足设计要求。     

Two-dimensional models for an electrode with adsorption sites

Through a new method, the following model is solved exactly in the framework of classical equilibrium statistical mechanics of two-dimensional Coulomb systems, for the special value=2 of the coupling constant: the mobile charges of a one-component plasma are attracted by a line of equidistant sticky adsorption sites embedded in a background, the density of which varies in the direction orthogonal to the line. First the general expressions are given for the densities and correlation functions of nonadsorbed and adsorbed particles. Then these results are used to investigate two models of electrodes with localized adsorption: the externally charged hard wall and the impermeable polarized membrane. In each case the influence of the adsorption upon macroscopic features is studied: the potential drop across the interface, the contact theorem, and the Lippmann equation, which involves the surface free energy.     

Sum rules for the one-component plasma with additional short-range forces

It is proved that, in the one-component plasma, with interactions including a non-Coulombic short-range part, the density derivative of the correlation functions _n (r ₁,,r _n) can be simply expressed as an integral of _n+1(r ₁,,r _n+1). This result is applied to prove the relation between the fourth moment of ₂ and the compressibility.     

Molecular design of three-dimensional artificial extracellular matrix: Photosensitive polymers containing cell adhesive peptide

A photodimerizable monomer, methacrylic acid-(7-coumaroxy) ethyl ester, was synthesized and was copolymerized with a hydrophilic monomer (N,N-dimethylacrylamide) to obtain a water-soluble photosensitive polymer. Irradiation of the copolymer film and aqueous solution with a high-pressure mercury lamp resulted in highly hydrated gel. The gel yield was enhanced with the content of the photodimerizable group in the copolymer and the irradiation time. The degree of swelling of the gels decreased concomitantly. Incorporation of the well-known cell adhesive peptidyl ligand Arg-Gly-Asp-Ser(RGDS) into photosensitive copolymers attained a biologically active hydrophilic gel matrix upon UV light irradiation. Irradiation of a buffer solution of the latter copolymer premixed with smooth muscle cells entrapped the cells throughout the gel matrix. This indicates that the designed polymer and the resulting cell-incorporated hydrogel are biomimic to an extracellular matrix and to the media of the vascular wall, respectively. © 1993 John Wiley & Sons, Inc.     

Frictional behaviors of three kinds of nanotextured surfaces

Nanodot‐textured surface, nanorod‐textured surface and nanocomposite‐textured surface were prepared by the hydrothermal technique and successive ion layer absorption and reaction technique. The adhesion and friction properties of the three kinds of nanotextured surfaces were investigated using an atomic force microscope colloidal probe. Experimental results revealed that the nanorod‐textured surface and nanocomposite‐textured surface can significantly reduce adhesive and friction forces compared with a nanodot‐textured surface. The main reason for this phenomenon was that the nanorod and nanocomposite textures can reduce contact area between the sample surface and the colloidal probe. The effects of surface root mean square roughness, applied load and sliding velocity on the adhesion and friction behaviors of the nanotextured surfaces were investigated. The adhesive and friction forces of the nanotextured surfaces decreased with the increasing surface root mean square roughness. Compared with the nanocomposite‐textured surface, the nanorod‐textured surface has better adhesion and frictional performance. Copyright © 2016 John Wiley & Sons, Ltd.     

Strong,Removable, and Photoluminescent Hyperbranched Polyamide-amine Hot Melt Adhesive

The development of adhesive technology is gaining increasing attention in machinery, electronics, aviation, and other fields. However,traditional adhesives are difficult to be peeled and removed after cross-linking and curing due to the limited solubility in common solvents, which causes pollution and damage to the surface of the adherend. In this work, we synthesized random hyperbranched polyamide-amine hot melt adhesives through Michael addition of 1,8-octanediamine and N,N'-methylene diacrylamide(ODA-RHP HMA). Owing to the presence of various polar groups, ODA-RHP HMA exhibited robust lap shear strength to different substrates, including glass(6.6 MPa), ceramics(10.3 MPa), steel(11.5 MPa), and aluminum(11.8 MPa). Due to the hydrogen bonds in ODA-RHP, the HMA demonstrated intrinsic self-healing ability, which can be used repeatedly when being subjected to cyclic heating and cooling. Since ODA-RHP HMA can be swollen or dissolved in ethanol, the adhesives can be easily removed through erasing. In addition, ODA-RHP exhibited aggregation-induced luminescence due to the tertiary amine structure in the molecular structure of ODA-RHP, which can be used in the field of cultural relics restoration.     

Mechanisms and applications of bioinspired underwater/wet adhesives

In nature, many organisms can effectively fix to contact substrates and move and prey in complex living environments, such as underwater, seawater, and tidal environments, owing to special secreted chemical components and/or special micro/nanostructures on the adhesive surface of these organisms. Inspired by the adhesive performance of organisms, extensive research related to adhesive components and adhesive surfaces has been conducted recently. To better understand the underlying adhesive mechanisms and facilitate further continuous inspiration, a brief overview of recent wet/underwater adhesive materials is provided herein. First, the adhesive processes and underlying mechanisms of commonly researched organisms, such as mussels, octopuses, clingfish, and tree frogs, are discussed, and the corresponding bioinspired artificial adhesives are presented. Then, the applications of these bioinspired adhesives, such as intelligent robots (signal monitoring and sensing devices), wearable devices (including wet climbing and electronic skin), biomedicines (including wound dressings, bone adhesion, and rapid hemostasis), are presented and summarized. Finally, we offer our perspective on the future challenges and development of bioinspired artificial adhesives.     

Synthesis and photopolymerizations of first monomers with phosphonate and bisphosphonate or phosphonic and bisphosphonic acid functionalities for potential dental applications

The first monomers containing both phosphonate and bisphosphonate (M1) or phosphonic and bisphosphonic acid (M2) functionalities are synthesized, aiming to improve binding abilities of self-etching adhesive systems and composites: An amine having both phosphonate and bisphosphonate functionalities is prepared via Michael addition reaction between diethyl (6-aminohexyl)phosphonate and tetraethyl vinylidene bisphosphonate, its reaction with 2-isocyanatoethyl methacrylate gives M1 which is converted to M2 by selective dealkylation of the phosphonate/bisphosphonate ester groups. Their copolymerization with commercial dental monomers (bisphenol A glycidyl methacrylate, triethylene glycol dimethacrylate, and 2-hydroxyethyl methacrylate) investigated by photo-differential scanning calorimetry shows adequate photopolymerization rate and conversion. X-ray diffraction, Fourier transform infrared, and X-ray photoelectron spectroscopy analyses of M2-treated hydroxyapatite particles show formation of stable M2-calcium salts. These monomers are assessed to be not toxic according to MTT standards by in vitro cytotoxicity studies with NIH 3T3, U2OS, and Saos-2 cells. All these properties make these monomers potential candidates as biocompatible components for dental adhesives and composites. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2739–2751