PAN共聚纤维的热氧化研究

本工作采用连续式实骏装置与方法,借助力学测试、X射线衍射、元素分析、红外光谱等技术,系统地研究了PAN共聚纤维在连续热氧化过程中化学、结构、性能间的联系,亦对PAN基碳纤维力学性能提高的途径进行了探讨。研究结累表明:在热氧化过程中,PAN共聚体系的热化学反应主要发生在250℃左右;其间纤维的序态结构变化剧烈,易使纤维产生结构缺陷,进而影响热氧化纤维力学性能的变化。     

叔丁醇氧化产物的气相色谱分析

介绍了用气相色谱分析叔丁醇两步氧化制甲基丙烯酸液相产物的组成，该分析方法能够分析液相产物中的醛类，酮类和酸类化合物共计9个组分，C2－C4有机酸无记忆效应，其色谱峰不拖尾，该分析方法的相对标准偏差≤8．5％，回收率在94．5％－103．7％之间，是一种快速，准确，操作简单的分析方法。     

回火处理对高碳冷拔钢丝强度和塑性的影响

研究了６５钢冷拔钢丝在５００℃不同时间回火时的抗拉强度和延伸率的变化。试验结果发现，在回火初期，抗拉强度首先增长，然后随口火时间的延长连续降低，而延伸率始终在增长，增长速度是先快后慢。这种行为可归因于第一内应力的消除和ε－碳化物在形变铁素体中的析出以及后来再结晶的发生。     

Thermal Diffusivity in Supercritical Fluids Measured by Thermal Lensing

Thermal diffusivities of supercritical CO₂ and C₂H₆ were determined over a wide density range with a photothermal technique. The thermal lens, formed by the degradation of the absorbed light energy as heat by the sample, allows the employment of a nonequilibrium method in the critical region. Controlling the refractive-index gradient, i.e., a density gradient, perturbations can be maintained at levels where convection is negligible. An easy-to-operate setup allowed us to measure thermal diffusivities in the density ranges 5 to 20 mol·dm^–3 for CO₂ at 308 and 313 K and 2 to 12 mol·dm^–3 for C₂H₆ at 308 K with a standard precision of 15%.     

Dynamic properties of carbon black filled chlorinated polyethylene/hindered phenol blends

Aggregates of carbon black (CB) in a polymer matrix have a tendency to form a CB network. The dynamic mechanical properties of binary systems of chlorinated polyethylene (CPE) and CB or 3,9‐bis{1,1‐dimethyl‐2[β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) and their ternary systems were investigated. It was found that the dynamic mechanical properties of those systems depend on the colloidal properties, surface oxides, and surface modification of CB. For binary systems of CPE and CB, oxidized CB gives a high modulus at low strain amplitude and a large Payne effect compared with untreated CB. In contrast, the reverse effect was observed for their ternary systems. Consequently, a good micro‐dispersion is obtainable by surface modification due to physical adsorption of AO‐80 on oxidized CB particles via hydrogen bonds. © 2003 Society of Chemical Industry     

催化部分氧化法制氢的水碳比控制与探讨

简要介绍了国内少有的干气催化部分氧化转化制氢工艺,重点讨论了转化水碳比的控制条件,对降低水碳比操作进行了有益地探讨。     

Works of adhesion at the carbon fiber-liquid interface determined using a modified wetting technique

Works of adhesion W_SL between aqueous solutions with pH values in the range from 1 to 14 and carbon fibers from different sources, which were additionally treated in an inert atmosphere or in oxygen, were measured by use of a microbalance. These works of adhesion W_SL were found to show distinct stepwise dependencies on the pH value. The works of adhesion W_SL are attributed to dispersion interactions W_SL¹ and various acid-base interactions w_sl^ab—in the latter case between the acidic and basic surface groups of carbon and the various basic and acidic aqueous solutions.     

活性炭单柱提取肌苷新技术研究

活性炭单柱提取肌苷新技术研究李永泉，张进，姚恕，郑莲英，俞峰（杭州大学生物系杭州３１００２８）（浙江大学化工系杭州３１００２７）关键词：肌苷，提取技术，活性炭单柱１前言目前，国内肌苷发酵后处理工艺落后，在分离提取工序中肌苷损失严重，收率一般只有５０％...     

Asbestos replacement aspects: Modification of the fibre-matrix interphase in lonomer based composites

Asbestos fibres, of the chrysotile variety, and chopped carbon fibres were pretreated by an in-situ polycondensation technique eventually resulting in a polyamide coating on the fibre surface. Ionomer based composites containing either carbon or asbestos fibres in random in plane fibre orientation were prepared, and the influence of this coating process on the tensile properties was investigated. It was found that for the asbestos-filled composites the presence of the nylon 6,6 interlayer improves the tensile performance, especially at moderate polyamide depositions. This is not the case with the pretreated carbon-filled composites for which carbon fibres with higher polyamide contents are preferred. Combinations of the treated asbestos fibres with carbon and/or aramid fibres may be used to reduce the asbestos content in asbestos-only based engineering plastics.