聚酯消光剂加入工艺的改进

介绍消光剂加入位置由浆料釜改为第二酯化釜的情况。工艺做适当调整后,产品质量除DEG含量略有升高外,其他指标无大的变化。转产时间节约了一半,减少大量过渡产品,降低了生产成本。     

PET装置在线转产中过渡时间与过渡料的控制

推导了PET装置在线转产过渡时间及过渡料产量的计算公式,并应用于实际生产中,分析装置在线转产的影响因素。结果表明:大有光产品在线转产半消光产品,将合格半消光产品的二氧化钛(TiO2)低限边界浓度wTiO2由0.30%降为0.25%,转产时间缩短45%以上,半消光产品在线转产大有光产品,将合格大有光产品的TiO2高边界浓度wTiO2由0增加为0.005%,转产时间由30.37 h降至11.34 h。转产过程中反应器的液位、转产产能和添加剂的流量是影响转产过渡时间和过渡料产量的关键因素。     

熔体直纺半消光/大有光涤纶POY的转产工艺优化

在现有400 kt/a聚酯装置的基础上,对2条半消光涤纶预取向丝(POY)生产线进行技术改造,转产大有光涤纶POY.结果表明:通过在装置大有光涤纶POY生产线预留一个管道开口,加装输送管道连接2条半消光涤纶POY生产线,在接口处加装三通阀,同时优化转产工艺参数,转产大有光涤纶POY,产品质量稳定,达到AA级标准;以转产...     

大型聚酯工业装置转产操作优化

针对连续化大型聚对苯二甲酸乙二醇酯(PET)生产装置,采用Aspen流程模拟开发平台建立了基于组合流动模型的非理想流动的动态转产模型。以装置运行效益最大化为目标,考虑设备、工艺等限制因素,优化转产添加策略。以有光聚酯转产消光聚酯为例,研究表明,聚酯反应釜中物料流动偏离理想流动;消光剂添加策略宜采用分步添加方式,转产实施后,过渡时间时显缩短,装置运行效益显著提升。     

有光与半消光聚酯切片生产的成功转换

通过估计物料的停留时间，利用熔体调整的优点，使得在从有光切片转产半消光切片过程中，可以不产生微消光产品，没时用特制ＴｉＯ２配制悬浮液，不需碾磨、沉降，悬浮液可直接加入酯化釜中。     

含凝胶消光PVC树脂的消光性能研究

介绍了消光聚氯乙烯树脂的性能，研究了聚合度、凝胶含量、膨润度、交联剂等对消光性能的影响，以及增塑剂用量、加工温度、混炼时间等对制品消光性能的影响，并探讨了消光原理。     

聚合物消光剂

简单介绍了消光机理、消光剂的定义及分类，并对无机消光剂和聚合物消光剂进行了比较。     

聚合物消光膜

本文介绍了聚合物消光膜定义、应用、国内外生产概况、常见生产工艺和原料及结构,也概括了消光作用及其实现手段,最后考察了原料和加工工艺方面对消光膜消光性能的影响。     

超细二氧化硅消光剂

超细二氧化硅消光剂具有易于分散、加入量小、化学惰性高、消光性能好等特点,广泛应用在各种消光涂层和消光材料中,是重要的消光产品。文章综述了合成超细二氧化硅消光剂的种类、制备方法,介绍了其消光原理、消光度的影响因素以及未来发展方向。     

XG型消光剂消光作用原理探讨

本文制备了一系列聚合物组成不同的消光剂,采用聚合物光学性能表征及扫描电镜分析,研究结果表明,光对电子的极化作用越小,消光作用越强,其作用是这类电子产生强迫振动,成为二次波源并向各方向发射,从而产生消光。     

肼类推进剂猝灭剂猝灭效果研究

通过采用六氟异丙醇等材料合成出对甲苯磺酸六氟异丙酯,研制了肼类推进剂猝灭剂。对比结果表明,自制的肼类推进剂猝灭剂对偏二甲肼的猝灭效果优于氟蛋白泡沫灭火剂,预装了肼类推进剂猝灭剂的猝灭器产生的压缩空气泡沫对偏二甲肼的猝灭效果更好,自制猝灭剂的猝灭效果相当于国外的同类泡沫灭火剂。     

Light scattering and extinction in polydisperse systems

A simple approach to predict transmittance spectra of polydisperse systems is recalled and applied to various model systems (spinel-like particles in water, pores in a spinel-like matrix) and real systems (spinel in water, diamond in water, amorphous carbon soot in isopropanol) in order to investigate principal effects of size distributions (normal/lognormal, narrow/wide, monomodal/bimodal, shift of mode positions, shift of mode heights) and optical properties (refractive index contrast, with or without absorption) on the in-line transmittance. A comparison of predicted and measured spectra showed that size distributions with more small particles cause a more significant decrease in transmittance (at least for sufficiently short wavelengths) and that laser diffraction may seriously underestimate the amount of small particles (for absorbing particles, for which the influence on transmittance is enormous, a difference of up to 30% in absolute transmittance measured via spectrophotometry has been found against predictions based on laser diffraction results).     

七氟丙烷气体灭火系统设计

本文对几种哈龙替代物进行了比较分析，并介绍了七氟丙烷灭火系统的组成及原理，结合大庆房屋产权档案库气体灭火系统的设计，介绍了七氟丙烷灭火系统的设计。     

Measurement of the extinction coefficients of magnetic fluids

A novel spectral transmittance approach for measuring the extinction coefficient of magnetic fluids is proposed. The measuring principle and accuracy of the approach are analysed. Experiments are conducted to measure the extinction coefficient of magnetic fluids with different particle volume fractions. The relative uncertainty of experimental data is less than 1.8%. The experimental results indicate that the extinction coefficient of magnetic fluids increases with increase of the volume fraction of suspended magnetic nanoparticles and the optical properties of the particle material have a significant effect on the extinction coefficient of the magnetic fluids.     

Changes of pleochroism and extinction contours in carbonaceous mesophase

Reflected polarized-light micrography using crossed polarizers with a gypsum plate has been employed to investigate the microstructure of carbonaceous mesophase formed at the early stage carbonization of pitches. It follows from the changes in pleochroism and in isogyres occurring with the stage rotation, that a simple mesophase spherule is optically a uniaxial positive liquid crystal belonging to the hexagonal system with a straight extinction. Observations of changes in pleochroism and in extinction contours for coalesced and for deformed mesophases, permit to distinguish crosses from nodes and by that to identify four types of linear defects in the stacking of the aromatic layer planes. It is explained schematically how the cross and nodal structures are formed in the coalescence of two simple spherules and in the deformation of such coalesced mesophase.     

A theory for flame extinction based on flame temperature

The extinction and suppression of diffusion flames is examined theoretically. The effects of oxygen reduction and external heat flux are examined compared to data in the literature. An application of extinction in compartment fires is also examined. The theory developed is based on a critical flame temperature, and that theory includes transient effects and the addition of water as well. Copyright © 2004 John Wiley & Sons, Ltd.