Enzyme electrode based on gold-plated polyester cloth

Summary Diaphorase is immobilized on electrodes derived from metal-plated polyester cloth by entrapment method and coupled with an electron mediator. Cyclic voltammogram depended on the existence of the substrate NADH (for oxidation) or NAD⁺ (for reduction) and the flavo-enzyme was shown to exchange electron(s) with the cloth electrode by mediation of the ferrocene derivative (for oxidation cycle) or the viologen derivative (for reduction cycle), even in the immobilized state. Coupling of the NADH or NAD⁺ regenerating system with alcohol dehydrogenase was examined.     

玻璃纤维布/苎麻纤维布混杂增强不饱和聚酯树脂的研究

采用玻璃纤维布与苎麻纤维布混杂增强不饱和聚酯(UP)树脂制备复合材料,研究玻纤布与苎麻布的相对比例及偶联剂处理对复合材料力学性能的影响,研究了不同复合材料的吸水性并与玻璃纤维复合材料和苎麻纤维复合材料二者进行了比较。结果表明,混杂纤维增强复合材料的拉伸强度、拉伸模量随混杂纤维中苎麻布含量的增加而下降,弯曲强度及弯曲模量在混杂纤维中苎麻布与玻纤布的比例为10∶20和15∶15时分别达到最大值188.09 MPa和1.56 GPa;所有偶联剂处理均可明显改善复合材料的拉伸模量及弯曲模量,硅烷类偶联剂的效果更佳,NDZ401可使复合材料的拉伸强度得到最大幅度(37.66%)的提高,而KH570及NDZ401对改善弯曲强度效果最佳;复合材料吸水后,厚度变化率大于宽度变化率,温度升高,复合材料吸水后尺寸变化率及吸水率均增大,混杂纤维复合材料的吸水率与玻纤布复合材料的吸水率相近,远低于苎麻布复合材料的吸水率。     

Water-containing resin based on unsaturated polyester

Unsaturated polyester resins containing water were prepared through two steps: formation of a stable W/O emulsion of polyester prepolymer and subsequent polymerization of the emulsion. In this paper, conditions for formation of the resins from the W/O type emulsion and the heat-protection properties of the resulting water-containing resins are reported. The stability of the emulsions was measured, and the results are discussed in relation to the gelation time, since the polymerization of the emulsions is required to proceed faster than their disintegration. It was found that with increasing viscosity of the emulsions their stability increases and the gelation time shortens. The above requirement is fulfilled at almost all regions of emulsifier concentration where stable W/O emulsions are formed. Water-containing unsaturated polyester resins exhibit a remarkable heat-protection effect at elevated temperatures (500 and 2500°C.) in comparison with polyester resins not containing water.     

Electrolytic determination of exposed tungsten on gold-plated tungsten

The relative area of exposed tungsten on gold-plated tungsten wire has been determined by measuring the corrosion potential in KOH. Calibrations were carried out using short-circuited gold and tungsten samples of various geometries and using gold-plated tungsten wire with spots etched through the gold. Differences in potential were found between flat gold foil and gold wires of various diameters unless vigorous air agitation was provided. Twenty two samples of commercially prepared Au plated tungsten wire were measured by this technique. The average surface fraction of tungsten exposed was 0·0014; with values observed from a minimium of 0·00025 to a maximum of 0·0047. The technique gives quantitative results, is rapid to use, and appears reasonable as a quality-control procedure.     

Nanocomposites based on montmorillonite and unsaturated polyester

The concept of nanoscale reinforcement provides opportunity for synthesis of new polymer materials with unique properties. Montmorilonite (MMT) was derived from bentonite, purified, activated by sodium ions and mixed with reacting unsaturated polyester (UP). X-ray and transmission electron microscopy data were in support of the formation of a partially delaminated nanocomposite material. At an MMT content of only 1.5 vol%, the fracture energy, G_Q, of the nanocomposite was doubled, 138 J/m² as compared with 70 J/m² for the pure UP.     

表面处理对剑麻纤维布/不饱和树脂材料性能影响

采用碱、高锰酸钾及热对剑麻纤维布进行了表面处理,并由真空辅助树脂传递模塑成型(VARTM)工艺制备了剑麻纤维布增强不饱和聚酯树脂复合材料。通过对复合材料的力学性能及吸水性的测试,研究了不同剑麻纤维布表面处理对其不饱和聚酯树脂复合材料性能的影响。结果表明:经过碱处理,复合材料的拉伸、弯曲,冲击强度提高最大,可分别提高26.5%,16.5%和22.6%,吸水率降低了47.5%。对剑麻纤维布进行表面处理可使复合材料的界面性能得到改善,力学性能提高,吸水性降低。     

Effect of external flaws in texturized polyester yarns on the quality of cloth made from them

All-Russian Scientific-Research Institute of Polymer Chemical Fibres, Moscow. All-Russian Scientific-Research Institute of Synthetic Fibres, Tver'. Translated from Khimicheskie Volokna, No. 6, pp. 53–54, November–December, 1992.     

含硼苯并噁嗪玻璃布层压板的研制

以甲醛、苯酚、硼酸和二元胺为原料合成了含硼苯并噁嗪树脂(BBZ)。采用核磁共振仪、红外光谱仪、DSC及TGA分析研究了BBZ树脂的结构,树脂及其固化物(PBBZ)的热性能,并对树脂溶液和浸胶布的性能以及层压板的力学和电性能进行了测试。结果表明,BBZ具有较好的热稳定性;PBBZ的玻璃化温度(Tg)为183℃,并具有优良的热分解稳定性,5%热失重温度为423℃,800℃残炭率为65%。其层压板具有较好的热态保持率(180℃为74.5%,200℃为58.9%),燃烧等级达到V-0级,同时具有较好的电性能和力学性能。     

以声学处理聚酯为基础的聚氨酯

以经声学处理过的聚己二酸乙二醇酯（∏b）为基础的聚氨酯可以简化合成工艺,免除聚酯的烘干阶段,且能合成出合格的力学性能优良的聚氨酯。除此之外,还可以缩短聚氨酯的热固化时间及恒温调节时间,达到节能减排和保护环境的目的。     

Highly flexible supercapacitors with manganese oxide nanosheet/carbon cloth electrode

We report a simple and cost-effective synthesis of hierarchically porous structure composed of Birnessite-type manganese dioxide (MnO₂) nanosheets on flexible carbon cloth (CC) via anodic electrodeposition technique. Petal-shaped MnO₂, having sheet thickness of a few nm and typical width of 100 nm, with a strong adhesion on CC is observed. This hierarchically porous MnO₂–CC hybrid structure dose exhibit not only excellent capacitance properties, such as up to 425 F g⁻¹ in specific capacitance, but also high crack resistance owing to its efficient release of bending stress, as observed by cyclic voltammetry and galvanostatic charge/discharge measurements under different curvature of bending configurations. Furthermore, flexible supercapacitors based on this kind of MnO₂ nanosheet/CC electrode showed significantly improved stability in capacitive performance over 3000 cycles under the bending test, which is highly promising for future applications in flexible energy storage device.     

Moisture-cured polyurethane based on polyester and polycarbonate polyols

Moisture-cured polyurethanes were prepared by reacting toluene diisocyanate and sebacic acid-based hydroxy esters such as ethylene glycol sebacate, propylene glycol sebacate, diethylene glycol sebacate, and polyester polyols such as poly(ethylene glycol sebacate), poly(propylene glycol sebacate), poly(diethylene glycol sebacate), and poly(butane diol sebacate). The effect of molecular weight of the esters on film properties and the catalytic effect of 3–5% triethylamine, triethanolamine, and 2-diethylaminoethanol on curing of such films were investigated. Polyurethanes were also prepared using a blend of poly(butane diol carbonate) polyol with polyester polyols. Best polyurethane compositions were obtained when sebacic acid-based polyester polyols were blended with poly(butane diol carbonate) polyol in the ratio of 3:2. These polyurethanes show good tensile strength (120–215 kg/cm²) and elongation (340–460%) properties, having high melting points (247–268°C) and good resistance to solvents and chemicals. Moreover, they are colorless and transparent.     

生物基EG聚酯的合成及性能研究

利用生物基EG合成聚对苯二甲酸乙二醇酯,并与石油基EG进行了对比。结果表明,生物基EG无DEG、TEG等高沸点微量组分,220 nm紫外透过率略低;用生物基EG合成聚酯时,酯化出水速率和缩聚速率略快;生物基EG合成聚酯的端羧基和熔融结晶温度较低,流变性能与石油基EG合成聚酯相当。     

Carbon nanotube cloth as a promising electrode material for flexible aqueous supercapacitors

Journal of Applied Electrochemistry - Electrochemical cyclic recharging of a binder-free flexible carbon material in respect to supercapacitor applications is reported. To provide high enough and...     

Biophysical studies on bone cement composites based on polyester fumarate

In this study poly(vinlyl chloride) (PVC) was modified by using ethylenediamine, diethylenetriamine, and ethanolamine as a crosslinker in dimethylformamide. Reaction variables were optimized for getting desired crosslinked PVC, which was further reacted with maleic anhydride to form graft polymer. The anhydride group on further hydrolysis gives carboxylic group, which can exchange proton with other cations.The polymers were characterized by FTIR spectroscopy and thermal analysis (TGA/DTA). Swelling behavior was examined in various electrolytic solutions. Modified PVC have shown good thermal stabilities and absorption capacities in neutral and acidic media, due to which these polymers might find applications in cation exchanger resin and chromatography. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

UV curing of composites based on modified unsaturated polyester

Synthesis and photocrosslinking of glass fiber-reinforced composites, based on epoxy acrylate-modified unsaturated polyester, have been investigated. The efficiency of the photocrosslinking process for glass fiber laminates of the polyesters that contain different comonomers has been evaluated by measuring mechanical properties. The data show (i) that 2 mm thick laminates, containing 30–40% glass fiber mats, are cured with UV irradiation for 15 sec at room temperature in air; (ii) that multifunctional acrylate or acrylether monomers added to the polyester resin improve the tensile and flexural properties of the photocured product to a greater extent than do added allylic monomers, due to the different photocrosslinking mechanisms; (iii) that the physical properties of the photocrosslinked laminates are well correlated with the molecular weight of the polyester, the amount of multifunctional monomer added, and the glass fiber content. © 1994 John Wiley & Sons, Inc.     

Enzymatic hydrolysis of polyester based coatings

The potential of two hydrolytic enzymes, namely a lipase from Thermomyces lanuginosus (TlL) and a cutinase from Humicola insolens (HiC) for hydrolysis of the phthalic acid backbone based polyester coatings was assessed. Two phthalic acid/trimethylolpropane based model substrates resembling the structure of the polyester backbone of coatings were synthesized. Out of both enzymes, only the cutinase was able to hydrolyze both model substrates while the larger substrate was hydrolyzed at a lower rate. The cutinase was also able to hydrolyze a coating (alkyd resin) both in suspension and as dried film. LC–MS analysis of the hydrolysis products released from the coating revealed the presence of oleic acid, its monoglyceride, phthalic acid and 2-((3-((2-((2,3-dihydroxypropoxy)carbonyl)benzoyl)oxy)-2-hydroxypropoxy)carbonyl)benzoic acid. These results indicate that the enzyme was able to hydrolyze the polyester backbone as well as to release fatty acid side chains. Consequently, enzymatic hydrolysis has a potential for the removal of coatings, their recycling or their functionalization.     

Side-chain polyesters and polyester hydrochlorides based on terephthalic acid

Side-chain polyesters and polyester hydrochlorides were synthesized from α-(bis(2-hydroxyethyl)amino)-ω-(4′-methoxy biphenyl-4-oxy) alkanes with different spacer lengths (Cn-diol, n=6, 8, 10) and terephthaloyl chloride. Since N-substituted diethanolamine acts as a stronger acid acceptor than triethylamine or pyridine, polyester hydrochlorides are formed during polyesterification instead of polyesters. Polyesters can be prepared from a chloroform solution of polyester hydrochlorides by extraction of HCl. During the polyesterification, linear polymers as well as cyclic oligomers are formed. All polymers were analyzed by ¹H NMR, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), X-ray spectroscopy (XND) and polarizing optical microscopy (POM). Polyesters and polyester hydrochlorides differ greatly in solubility and thermal properties. Although no liquid crystalline phase transitions were detected for either kind of polymer, an ordered structure was observed in XRD experiments for both polymers and was ascribed to a crystal smectic E phase.     

Unsaturated polyester based on poly(ethylene glycol)

Unsaturated polyesters were prepared by one-stage melt condensation of maleic anhydride, phthalic anhydride, propylene glycol, and poly(ethylene glycol)s with different molecular weight, and the properties of their castings from styrenated resins were investigated. Tensile and flexural properties decrease with the increase of molecular weight of poly(ethylene glycol), but impact strength, elongation, and water absorption have an inverse effect. This study improves the understanding of the effect of chain length of poly(ethylene glycol) in unsaturated polyester on the properties of its castings.     

Composite materials based on polyester resin and chemical fibres

The essential role of the strength, textile structure, and compatibility of reinforcing chemical fibres with the polymer binder in formation of the structure and properties of composite materials based on polyester resin was demonstrated. Technical documentation was developed for fabrication of polyester prepregs reinforced with chemical fibres and their processing into articles by compression molding. Translated from Khimicheskie Volokna, No. 4, pp. 20–22, July–August, 1998.     

Pt电极双酶生物传感器的研究和应用

在双酶(乳酸脱氢酶、丙酮酸氧化酶)体系中加入乳酸时,在一定的范围内,随着乳酸浓度的增加,该体系发光强度不断增加。这是由于乳酸与乳酸脱氢酶在辅酶I的作用下,反应生成丙酮酸,丙酮酸同空气中的氧气在丙酮酸氧化酶的作用下反应产生的过氧化氢可以增敏鲁米诺的电化学发光。将双酶通过碳纳米管附载的方式修饰在电极表面上,得到的修饰电极对鲁米诺电化学发光产生的增敏作用是裸电极的2倍多,且修饰后的最低定量限为8.9×10-12 Mol/L。并将它应用于人体汗液中乳酸的测定及其运动员耐力训练水平的预测,得到的结果满意,重现性高,稳定性好,酶膜不容易脱落。