新型难燃输送带胶粘剂的研制

以改性氯丁橡胶为主料、多异氰酸酯为固化剂制成的新型难燃输送带胶粘剂,具有粘接强度高、耐热性好、干燥时间短、难燃等特点,在常温常压下粘接输送带接头,固化30min即可负荷运行。     

Continuous formation of slurry ice by cooling water–oil emulsion in a tube

Water-silicone oil emulsion with an additive, (C₂H₅O)₃SiC₃H₆NH₂, was examined as a heat storage material. A spiral tube used as a heat exchanger was immersed in a low temperature bath and the emulsion was circulated in the tube to make ice continuously. Ice was separated from the ice–liquid suspension in an outlet tank. The amount of formed ice, the temperatures of the inlet and the outlet of the heat exchanger, and the temperatures in the tube wall were measured and the overall heat transfer coefficient and the heat flux through the tube were calculated. Experiments were carried out, varying the flow rate, the temperature of cooling brine, and the thickness of tube wall. The condition under which slurry ice was formed continuously without adhesion of ice to the cooling wall was clarified. Though decrease in the thermal resistance of the tube increased the rate of ice formation or raised the brine temperature, it narrowed the range of the flow rate and of the brine temperature in which slurry ice was formed continuously.     

Investigations of surface characterization of silicone rubber due to tracking phenomena under a.c. and d.c. voltages

In the present work, tracking phenomena has been studied with silicone rubber material under the a.c. and d.c. voltages following IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric differential thermal analysis (TG-DTA) studies. The tracking time was different for a.c. and d.c. voltages.     

Thermoplastic elastomeric composition based on maleic anhydride–grafted ground rubber tire

Ground rubber tire (GRT) powder was maleated in an internal mixer using maleic anhydride and dicumyl peroxide at 160°C. Maleated GRT was characterized by using X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, wettability, and differential scanning calorimetry. The physical properties of the dynamically vulcanized 60 : 40, rubber : plastic composition based on acrylated high‐density polyethylene as the plastic phase and ethylene propylene diene rubber containing maleated GRT as the rubber phase were found to be greater than the corresponding composition containing nonmaleated GRT. The blend was found to be reprocessable, like themoplastic elastomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 370–378, 2002; DOI 10.1002/app.10348     

Development and characterization of magnetorheological polymer gels

Magnetorheological materials have been used in many applications in recent years. To develop new materials, polyurethane and silicone polymer gels were investigated. Rheology is qualitatively controlled for each system by controlling the concentration of reactants and diluents. The resulting polymers have solid, gel, or liquid states, depending on the crosslinking and dilution. The gels were characterized through kinetic analysis. Differential scanning calorimetry (DSC) was used with analysis methods to find the kinetic properties for diluted and undiluted polyurethane systems. Heat of reaction, order of reaction, preexponential constant, and activation energy were obtained from the experimental DSC data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2733–2742, 2002     

丁腈橡胶/导电粒子复合材料的正温度系数(PTC)特性

将导电粒子碳黑和铜粉分别与丁腈橡胶混合制备导电聚合物复合材料，其中碳黑（Ｎ５５０）／丁腈橡胶复合材料的电阻率随温度的变化呈现较强的正温度系数（ＰＴＣ）效应。讨论了掺入导电粒子浓度、结构和表面性质以及混炼硫化工艺等对该类材料的室温电阻率及ＰＴＣ效应的影响。     

Microstructure-related fracture toughness and fatigue crack growth behaviour in toughened, anhydride-cured epoxy resins

Fracture toughness and fatigue crack propagation (FCP) of plain and modified anhydride-cured epoxy resin (EP) were studied at ambient temperature. Liquid carboxyl-terminated acrylonitrile-butadiene (CTBN) and silicon (SI) rubber dispersions were used as tougheners for the EP. The morphology of the modified EP was characterized by dynamic mechanical analysis (DMA) and by scanning electron microscopy (SEM). The fracture toughness, K_c, of the compositions decreased with increasing deformation rate. K_c of the EP was slightly improved by CTBN addition and practically unaffected by incorporation of the SI dispersion when tests were performed at low cross-head speed, v. Both modifiers improved K_c at high v, and also the resistance to FCP, by shifting the curves to higher stress intensity factor ranges, ΔK, by comparison with the plain EP. It was established that both fracture and fatigue performance rely on the compliance, J_R, at the rubbery plateau, and thus on the apparent molecular mass between crosslinks, M_c. The failure mechanisms were less dependent upon the loading mode (fracture, fatigue), but differed basically for the various modifiers. Rubber-induced cavitation and shear yielding of the EP were dominant for CTBN, whereas crack bifurcation and branching controlled the cracking in SI-modified EP. The simultaneous use of both modifiers resulted in a synergistic effect for both the fracture toughness at high deformation rate and the FCP behavior.     

顺丁橡胶生产过程"门尼升值"的原因研究

研究了顺丁橡胶生产过程中门尼升值的原因。结果表明，顺丁橡胶生产后处理的膨胀干燥过程存在门尼升值现象。不同内在质量的顺丁橡胶门尼升值不同，正常条件下门尼升值发生于门尼粘度的测试过程。     

Y型密封圈橡胶模设计

介绍了Y型橡胶模具的设计 ,重点对模具结构和模腔尺寸进行了分析和阐述 ,经生产验证 ,此模具结构合理 ,定位可靠 ,操作方便 ,从而为同类产品的设计提供了参考。