RPF-AA改性纤维的制备及耐硫酸侵蚀性研究

通过对普通腈纶进行特殊预处理和改性,制备出一种具有良好抗浓酸侵蚀性的反应性高分子纤维材料,对改性纤维材料的化学(酸)稳定性、力学性能、微结构等特征性能研究表明:该纤维材料在120℃和98%浓硫酸环境条件下,经过20 min的侵蚀性处理后,其材料仍能够保持一定的力学性能和微结构,显示了突出的抗浓硫酸侵蚀性.     

Exhaust Emissions from an Engine Fueled with Biodiesel from High-Oleic Soybeans

Biodiesel is a fuel comprising mono-alkyl esters of medium to long-chain fatty acids derived from vegetable oils or animal fats. Typically, engines operated on soybean-based biodiesel exhibit higher emissions of oxides of nitrogen (NOx) compared with petroleum diesel. The increase in NOx emissions might be an inherent characteristic of soybean oil’s polyunsaturation, because the level of saturation is known to affect the biodiesel’s cetane number, which can affect NOx. A feedstock that is mostly monounsaturated (i.e. oleate) helps to balance the tradeoff between cold flow and oxidative stability. Genetic modification has produced a soybean event, designated 335-13, with a fatty acid profile high in oleic acid (>85%) and with reduced palmitic acid (<4%). This high-oleic soybean oil was converted to biodiesel and run in a John Deere 4045T 4.5-L four-stroke, four-cylinder, turbocharged direct-injection diesel engine. The exhaust emissions were compared with those from conventional soybean oil biodiesel and commercial No. 2 diesel fuel. There was a significant reduction in NOx emissions (α = 0.05) using the high-oleic soybean biodiesel compared with regular soybean oil biodiesel. No significant differences were found between the regular and high-oleic biodiesel for unburned hydrocarbon and smoke emissions.     

聚四氟乙烯改性剂的制备及性能

介绍了隔膜法氯碱所用的聚四氟乙烯改性剂，即聚四氟乙烯乳液、聚四氟乙烯纤维（SM-1）、聚四氟乙烯类纤维（SM-2）的制造原理、制造方法以及在隔膜法氯碱上的应用效果。     

Electro-oxidation of hydrazine on electrodes modified with vitamin B12

In this paper we report a kinetic study of the electro-oxidation of hydrazine catalyzed by vitamin B₁₂ pre-adsorbed on an ordinary pyrolytic graphite electrode. Kinetic parameters were determined by linear sweep voltammetry and rotating-disk electrode polarization curves. The order of the reaction is 1 in OH⁻ ions and Tafel plots give slopes of 80 mV/decade. A possible redox-catalysis mechanistic scheme is proposed.     

Mechanical properties and crosslink density of rare earth‐modified high‐abrasion furnace‐filled powdered natural rubber

High‐abrasion furnace‐filled powdered natural rubber [P(NR/HAF)] has more advantages than traditional HAF‐filled bale NR (NR/HAF) because of its better environmental performance and easier processing quality, but its lower mechanical properties are disadvantageous. To improve the mechanical properties, rare earth‐modified HAF‐filled powdered NR [P(NR/HAF‐Ln)] (Ln = Sm,La,Pr) was prepared by means of coacervation–coprecipitation, using rare earth‐modified HAF as separant and filler. The effect on mechanical properties of P(NR/HAF‐Ln) vulcanizate exerted by the emulsifier/HAF ratio, powdering temperature, Ln/HAF ratio and type of Ln, and HAF content were studied. The results indicated that when optimum formulation, the mechanical properties of P(NR/HAF‐Ln) vulcanizate were better than P(NR/HAF) vulcanizate. In addition, the relationship of the apparent crosslink density and HAF content of P(NR/HAF‐Ln), P(NR/HAF), NR/HAF vulcanizates was also investigated, along with their SEM microphotographs of tensile fracture surface, which indicated that the excellent mechanical properties of P(NR/HAF‐Ln) vulcanizate was attributed to correct amount of Ln that could increase crosslink density and reinforce the interface structure of NR matrix/HAF‐Ln particle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1755–1762, 2006     

有机硅改性丙烯酸乳液性能的研究

采用含乙烯基官能团的有机硅单体与甲基丙烯酸酯、丙烯酸酯和丙烯酸羟基酯等单体通过种子乳液聚合方法进行共聚,合成了有机硅改性丙烯酸酯共聚乳液,考察了有机硅单体用量对乳液机械稳定性、热稳定性、电解质稳定性和冻融稳定性的影响,同时还考察了乳液胶膜的机械性能和吸水率改进。     

环氧有机硅阳离子型光敏预聚物的合成及其光敏性能的研究

合成了环氧有机硅光敏预聚物及阳离子光引发剂甲苯茂铁四氟硼酸盐，研究光引发剂种类、预聚物与单体配比、增感剂结构等因素对固化速度的影响，发现预聚物体系的感度较高，最小感度值为165mJ/cm^2；并讨论了甲苯茂铁四氟硼酸盐的暗聚合能力。     

Nafion/ORMOSIL nanocomposites via polymer-in situ sol-gel reactions. 1. Probe of ORMOSIL phase nanostructures by Si solid-state NMR spectroscopy

A series of Nafion^®/ORMOSIL hybrids, generated by in situ sol-gel co-polymerizations of tetraethylorthosilicate (TEOS) and semi-organic R′_nSi(OR)_4−n co-monomers (SOC), were developed to generate a spectrum of nanoscale chemical environments within the Nafion^® morphological template. The molecular structures of the ORMOSIL phases were analyzed by means of ²⁹Si solid-state NMR (SSNMR) spectroscopy. A high average degree of Si atom coordination about SiO₄ molecular sub-units can be achieved, but a significant number of unreacted SiOH groups on reacted Q=Si(O_1/2)₄ units is always present. The shifting, with relative ORMOSIL composition, of D=RR′Si(O_1/2)₂ or T=R″Si(O_1/2)₃ (R, R′ and R″ are organic moeities) peak envelopes for difunctional or trifunctional SOCs is suggested to reflect random co-condensation rather than distinct Q and D (or T) block formation. The numbers of membrane-incorporated Q and D (or T) units per fixed sulfonate group were calculated from the ²⁹Si SSNMR spectra for those particular hybrids that had a reasonably low noise/signal aspect. Spectra for hybrids based on in situ sol-gel reactions for TEOS (no SOC present) suggest that inserted hydroquinone molecules interfere with condensation reactions between (RO)_4−xSi(OH)_x molecules and silanol oligomers to yield silicate structures with lower average coordination. While earlier small angle X-ray scattering studies indicated that ORMOSIL structures can be grown within the polar regions of Nafion^®, the results reported here address the specific compositions of these nanoscale structures.     

Interpenetrating polymer networks based on polyol modified castor oil polyurethane and poly(2‐ethoxyethyl methacrylate): Synthesis,chemical, mechanical,thermal properties,and morphology

Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC‐PU) and poly(2‐ethoxyethyl methacrylate) poly(2‐EOEMA) were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate (EGDM) as crosslinker. GC‐PU/poly (2‐EOEMA) interpenetrating polymer networks were obtained by transfer molding. The novel GC‐PU/poly (2‐EOEMA) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents thermal behavior (DSC, TGA) and mechanical behavior, including tensile strength, Young's modulus, shore A hardness, and elongation. The morphological behavior was studied by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1029–1034, 2004     

一种汉语方言编码与转换机制的研究

回顾了汉语拼音方案的组成和特点,分析了方言编码的可行性。引入二进制编码方式对汉字发音进行编码。编码序列包括了声母、韵母、音调、儿化音等编码部分。建立了方言音、修饰音、标准音之间的转换关系。以湘汨地区的方言为例,详细论述了方言编码和转换的过程。以人工代谢算法作为寻优策略,结合特定语言环境,将方言音转换成标准音。通过实例分析论述了该方案的可行性和合理性。