不同活化剂对石油焦基活性炭孔结构的影响

以石油焦为原料 ,Na OH,KOH和 Na2 CO3 为活化剂制备活性炭 ,采用氮气吸附考察了不同活化剂对活性炭的比表面积、中孔和微孔孔径分布、孔容积及平均孔径等孔结构的影响 .结果表明 :KOH活化制备的活性炭包含 1 nm的微孔和 4nm的中孔 ,总孔容 0 .648cm3 /g,比表面积大 ;Na OH制备的活性炭以 1 nm的微孔为主 ,占总孔容 ( 0 .1 65 cm3 /g)的 98% ,平均孔径 1 .83nm;Na2 CO3 制备的活性炭以 4nm的中孔为主 ,占总孔容 ( 0 .1 43cm3 /g)的 68.5 % ,平均孔径 3.42 nm,比表面积小 .3种样品的孔径都呈现出多峰分布特征 .KOH和 Na2 CO3 活化制备的活性炭的 N2 吸附脱附曲线属于 型 ,Na OH活化制备的活性炭吸附脱附曲线属于 型 .     

Electron Emission from Barium Strontium Titanate Ceramics

This paper focuses on understanding the influence of materials' properties on the ferroelectric electron emission. Ferroelectric ( x =1.0 and 0.8) and paraelectric ( x =0.67 and 0.5) compositions of barium strontium titanate (Ba _x Sr_{(1− x )}TiO₃) system were chosen for study based on their different ferroelectric and dielectric properties. Similar emission current waveforms were obtained from four compositions with negative triggering voltage applied to the rear electrode of the samples. It was difficult to explain the experimental results using the spontaneous polarization-switching model. The mechanism of electron emission from Ba _x Sr_{(1− x )}TiO₃ ceramics was ascertained to surface plasma emission.     

PVC助剂的新进展

介绍了近年来聚氯乙烯助剂的研制、开发的现状和趋势。     

Toughening by Metallic Lamina in Nickel/Alumina Composites

Tape casting and hot-pressing were used to produce metal/ alumina laminate composites. The mechanical behavior of these laminates was characterized. The strength and toughness of the laminates were greatly improved in comparison to that of monolithic alumina. Indentation strength values of the laminates remained approximately constant for indent loads between 10 and 100 N. Thus, this type of laminate appears to be a good candidate for damage-tolerant composite material design.     

碱土金属在萃取剂与树脂间反应平衡常数的测定

研究了碱土金属离子在Ｄ００１树脂与８－羟基喹啉三氯甲烷溶液间的平衡常数Ｏ－ｔＫ的测定。其值依Ｍｇ、Ｃａ、Ｓｒ、Ｂａ次序减小。并得出萃取剂浓度［ＨＡ］。与金属离子在两相分配的关系。     

NBR／EPDM的增容共混研究

本文采用第三组份增容途径,改善了NBR/EPDM并用胶的相容性、加工性和力学性能。通过对不同增容体系的研究对比,发现不同增容剂的增容效果差异很大,其巾以EVA-14增容效果最为显著,加入该增容剂的并用胶,在适当的工艺条件及硫化体系下,可获得最佳力学性能。本文还研究了不同增容剂对并用炭黑胶各种性能的影响,可以做到在不降低并用胶的力学性能的同时,提高并用胶的耐热空气老化、耐大气老化和耐臭氧老化性能.透射电镜实验和动态力学谱图证明了加与未加增容剂时,NBR/EPDM并用胶均为两相结构,增容剂起表面活性剂的作用,加强了两相界面间的相互作用,使分散相EPDM细微化和均匀化。     

PVC／PU合金的制备与研究

叙述了选择混炼型聚氨酯(PU)与分子量适中的Ⅱ型聚氯乙烯(PVC)树脂制备PVC/PU合金的过程,讨论了PVC/PU共混比、填充剂、硫化体系、共混工艺等因素对PVC/PU合金性能的影响。结果表明:选择PVC/PU=60/40(质量比),硫化剂TD15份,白炭黑30份,混炼温度140—160℃,可制得性能优良的PVC/PU合金。动态力学性能实验显示了PVC/PU合金有较好的相容性。     

PC/ABS合金研究进展

概述了PC/ABS合金国内外的开发应用现状,并综述了国内外近年来对PC/ABS合金的研究进展,其中包括:PC/ABS合金的相容性技术、相容剂的选用及影响合金性能的因素:原料、组分的配比、成型条件等,并对该合金的发展方向作了简要的分析,认为PC/ABS合金的开发研究在国内塑料合金的工业开发、应用中极其重要,开发的核心是相容化技术。     

A model for desulphurisation with limestone in a fluidised coal combustor

Kinetic expressions used to describe the reactions of deactivating catalyst particles are applied here to the sulphation of calcined limestone in a fluidised bed coal combustor where reactivity diminishes as pores fill with sulphate. Following closely the recent work of Fieldes and Davidson it is shown how experiments with batchwise addition of limestone to the combustor may be used to derive the two reaction rate constants of the system, k_s, and k_d, and how these may be incorporated into a two-phase model of a fluidised bed reactor to obtain predictions of desulphurisation efficiency under conditions of continuous operation. The resulting equation for SO₂ retention, η, may be simplified to:η = 1 ? [$\text{1}\text{1 +}\text{K}\text{β}$] where K is a function of limestone type and operating conditions and β is the calcium-to-sulphur mole ratio. The predictions of this equation are shown to be in agreement with experimental results.     

Catalytic activities and properties of mesoporous sulfated Al2O3–ZrO2

Mesoporous sulfated Al₂O₃–ZrO₂ (MSAZ) catalysts with large surface areas and pore volumes after calcination at high temperature (650 °C) and with higher Al₂O₃ content than 20wt% were successfully prepared from a template of block copolymer (P84). The MSAZ catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption, transmission electron microscopy (TEM), ²⁷Al magic-angle spinning nuclear magnetic resonance (MAS NMR), thermogravimetric analysis (TG–DTG), temperature-programmed desorption of ammonia (NH₃-TPD) and infrared spectra (IR) of adsorbed pyridine. It is shown that the resulting mesostructured sulfated Al₂O₃–ZrO₂ samples have a well-developed textural mesoporosity. The number of acid sites present on MSAZ catalysts is higher than that on conventional sulfated zirconia, and the former catalysts are more active than the latter one for various acid-catalyzed reactions.