Feasibility of conducting semi‐interpenetrating networks based on a poly(ethylene oxide) network and poly(3,4‐ethylenedioxythiophene) in actuator design

A new type of synthetic pathway—the use of interpenetrating polymer networks (IPNs)—is proposed to design conducting polymer‐based actuators. Two types of materials with interesting conducting properties were prepared: (1) a semi‐IPN between poly(3,4‐ethylenedioxythiophene) (PEDOT) and branched poly(ethylene oxide) (PEO) network; (2) a tricomponent IPN between PEDOT and a PEO/polycarbonate (PC)–based network as the ionic conducting partner. In the first case, the influence of the amount of branching in the PEO network on the EDOT uptake and electrochemical properties was studied. A maximum conductivity (15 S cm^?1) was obtained for 60 wt % branched PEO in the material. Moreover, the dispersion profile of PEDOT in the material was shown by elemental analysis and energy dispersion spectroscopy to follow a gradient through the thickness of the film leading to a built‐in three‐layered device. With respect to PEO/PC materials, the best results were obtained for about 80 wt % PEO in the matrix where the material remains sufficiently elastomeric. In this case, the conductivity reaches about 1 S cm^?1 for a 10 to 30 wt % polycarbonate content. These materials are capable of reversible 45° angular deflections under a 0.5V potential difference. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3569–3577, 2003     

PUR/EP/PPGDA三元IPN的光电子能谱研究

用X射线光电子能谱（XPS）分析了以聚氨酯（PUR）为第一网络的PUR／环氧树脂／聚－β－丙二醇二丙烯酸酯互穿聚合物网络（PUR／EP／PPGDA IPN）弹性体的表面元素分布，并用氩离子刻蚀进行材料内部元素分析。结果表明，三元IPN弹性体中主要元素C、O、N、Cl在材料表面和内部分布明显不一致，这种差异表明形成IPN后，三种组分聚合物在材料的表面和内部的分布是不均匀的，这种不均匀性与三种聚合物的比例有关。     

蓖麻油聚氨酯IPN黄变性能的研究

分别用2,4-甲苯二异氰酸酯(TDI)和六亚甲基二异氰酸酯(HDI)与蓖麻油反应制备出两种多异氰酸酯预聚体,再与交联剂(环氧树脂或烯类单体)反应制备出了不同的蓖麻油聚氨酯互穿网络型聚合物(IPN),通过黄色指数的测定,研究了体系组成对IPN黄变性能的影响。     

Thermal characteristics of interpenetrating polymer networks composed of poly(vinyl alcohol) and poly(N‐isopropylacrylamide)

Interpenetrating polymer networks (IPNs) composed of poly(vinyl alcohol) (PVA) and poly(N‐isopropylacrylamide) (PNIPAAm) were prepared by the sequential‐IPN method. The thermal characterization of the IPNs was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dielectric analysis (DEA). Depression of the melting temperature (T_m) of the PVA segment in IPNs was observed with increasing PNIPAAm content using DSC. DEA was employed to ascertain the glass‐transition temperature (T_g) of IPNs. From the result of DEA, IPNs exhibited two T_g values, indicating the presence of phase separation in the IPNs. The thermal decomposition of IPNs was investigated using TGA and appeared at near 200°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 881–885, 2003     

聚氨酯互穿网络防腐蚀涂料的制备

采用IPN方法,用丙烯酸树脂、聚丙烯腈、聚苯乙烯对蓖麻油聚氨酯进行共混改性,研究了改性后聚氨酯产物的红外光谱特征、耐化学腐蚀性、耐磨性、柔韧性等。结果表明:制得的聚氨酯互穿网络涂料的耐蚀性优异。     

Effect of Reaction Solvent on the Hydrogenation of Isophthalonitrile for Meta‐Xylylendiamine Preparation

This study focused on the effects of reaction solvent on the hydrogenation of isophthalonitrile (IPN) to produce m‐Xylylenediamine (MXDA) over Ni‐based commercial catalyst. The hydrogenation was carried out using various reaction solvents such as 1‐methylimidazole, mesitylene, benzyl ether and isopropanol under various reaction conditions. It was observed that 1‐methylimiazole outperformed the other reaction solvent, exhibiting a high MXDA yield and producing a low concentration of undesirable products.     

Semi‐interpenetrating polymer network beads of crosslinked chitosan–glycine for controlled release of chlorphenramine maleate

Spherical, semi‐interpenetrating polymer network beads of chitosan and glycine, crosslinked with different concentrations of glutaraldehyde were prepared for controlled release of drugs. The structural and morphological studies of the beads were carried out with FTIR and SEM techniques. The swelling behavior of the beads at different time intervals was monitored in solutions of different pH. Structural changes of the beads in response to solution pH were put forward using the data obtained from IR/UV spectral analysis. The release experiments were performed in solutions of pH 2.0 and pH 7.4 at 37°C, using chlorphenramine maleate as a model drug. The results indicate that, chitosan might be useful as a vehicle for controlled release of drugs. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 672–683, 2000     

Electrical response characterization of PVA–P(AA/AMPS) IPN hydrogels in aqueous Na2SO4 solution

Interpenetrating polymer networks (IPN) hydrogels composed of poly(vinyl acohol) (PVA) and poly(acrylic acid-co-2-acrylamido-2-methyl propyl sulfonic acid) (P(AA/AMPS)) were synthesized by solution polymerization. The IPN hydrogels were characterized using Fourier-transform infrared (FT-IR) and X-ray diffraction (XRD). The results indicated that strong hydrogen bond was formed between PVA and P(AA/AMPS), and the crystallinity of PVA in IPN hydrogels was declined significantly. The swelling/deswelling properties of IPN hydrogel in aqueous Na₂SO₄ solution were studied. When a sheet of water swollen IPN hydrogel (all the samples were swollen in deionized water) was placed in aqueous Na₂SO₄ solution, the IPN hydrogel shrunk. However, if a voltage was applied, the IPN hydrogel shrunk at high concentration of Na₂SO₄ solution, but swelled at low concentration. The results show that the critical concentration of Na₂SO₄ solution is about 0.005 mol/L. The stimuli response of the IPN hydrogel in electric field was also investigated. When water swollen samples were placed between a pair of electrodes in aqueous Na₂SO₄ solution, the IPN hydrogel showed significant bending behavior upon the application of an electric field. The bending direction of the IPN hydrogel depends on the concentration of Na₂SO₄ solution. At high concentration the IPN hydrogel bended toward anode, contrarily, at low concentration the IPN hydrogel bended toward cathode. The critical concentration of Na₂SO₄ solution is also about 0.005 mol/L. Further investigation showed that the gel component, concentration of aqueous Na₂SO₄ solution and the applied voltage influenced the bending speed of IPN hydrogel.     

聚氨酯IPN阻尼材料研究进展

介绍了互穿聚合物网络(IPN)材料的阻尼机理及其表征方法,并重点综述了聚氨酯(PU)IPN材料的研究进展。     

硝酸正丙酯和硝酸异丙酯的密度泛函理论研究

用密度泛函理论(DFT)中的B3LYP、B3PW91、B3P86方法研究硝酸正丙酯(n-propyl nitrate,NPN)和硝酸异丙醣(isopro- pyl nitrate,IPN)的平衡分子构型、前线轨道能(E_(HOMO)、E_(LUMO))、能差(△E=E_(LUMO)-E_(HOMO))和O-NO_2键的裂解能(BDE)。分析了两种硝酸酯分子和对应自由基的热稳定性。NPN和IPN中的O-NO_2键的裂解能用B3P86方法计算出最接近实验值。由O- NO_2键的裂解能符合文献中对应物质的表观活化能,推知两种物质的热分解反应只是单分子O-NO_2键的均裂反应。