THE OPPORTUNITIES AND CHALLENGE FOR EXISTING AND NEW CATALYTIC TECHNOLOGIES

ＴＨＥＯＰＰＯＲＴＵＮＩＴＩＥＳＡＮＤＣＨＡＬＬＥＮＧＥＦＯＲＥＸＩＳＴＩＮＧＡＮＤＮＥＷＣＡＴＡＬＹＴＩＣＴＥＣＨＮＯＬＯＧＩＥＳＸ．Ｄ．Ｈｕ（ＵｎｉｔｅｄＣａｔａｌｙｓｔｓ，ＩｎｃＬｏｕｉｓｖｉｌｌｅ，Ｋｅｎｔｕｃｋｙ，ＵＳＡ）Ａｂｓｔｒａｃｔ：...     

RSI独具特色的DMTAIV

ＲＳＩ独具特色的ＤＭＴＡＩＶ温特美国流变仪科学有限公司美国流变仪科学有限公司（ＲｈｅｏｍｅｔｒｉｃＳｃｉｅｎｔｉｆｉｃＩｎｃ．）带有高级操作和分析软件的热分析仪如：ＤＳＣ，ＴＧＡ，ＤＭＴＡ，ＴＭＡ，ＳＴＡ，ＤＥＴＡ等，流变仪如ＡＲＥＳ，ＳＲ２００／５...     

国内外增强用玻璃纤维的现状与发展

国内外增强用玻璃纤维的现状与发展林树益，高建枢，朱晶莹（南京玻璃纤维研究设计院２１００１２）ＳＴＡＴＵＳＡＮＤＤＥＶＥＬＯＰＭＥＮＴＯＦＲＥＩＮＦＯＲＣＥＤＧＬＡＳＳＦＩＢＥＲＡＴＨＯＭＥＡＮＤＡＢＲＯＡＤ￥ＬｉｎＳｈｕｙｉ；ＧａｏＪｉａｎｓｈｕ；Ｚ...     

新型加成型硅橡胶灌封胶的研究

本文合成了两种新型加成型硅橡胶：ＴＡＳ硅橡胶和ＭＤＡＳ硅橡胶。与通常使用的乙烯基加成型硅橡胶相比，ＴＡＳ或ＭＤＡＳ硅橡胶的固化条件与之相似，但ＴＡＳ－ｐｔ和ＭＤＡＳ－ｐｔ固化体系对许多能阻滞乙烯基加成型硅橡胶固化的物质不敏感。另一方面，ＴＡＳ－ｐｔ和ＭＤＡＳ－ｐｔ固化体系对许多材料（尤其对金属）呈现良好的粘接性能，且当样品浸于水中１５天后，仍保持其粘性。上述性能，使之具有许多用途。本文还讨论了ＴＡＳ和ＭＤＡＳ生胶的合成方法，以及影响ＴＡＳ、ＭＤＡＳ固化的若干因素。     

EDTA络合滴定法间接测定水泥中SO3

ＥＤＴＡ络合滴定法间接测定水泥中ＳＯ_３郑礼胜，王士龙，张虹山东建材工业学院（２５００２２）基于形成ＢａＳＯ４沉淀而建立的ＥＤＴＡ络合滴定法间接测定硫酸根，是采用加入过量的ＢａＣｌ２将其沉淀为ＢａＳＯ４，再用ＥＤＴＡ滴定剩余的Ｂ２２［１－３］，或者是?..     

三氧乙基化十二醇醚磺酸盐与某些阳离子表面活性剂复配体系的表面…

本文研究了三氧乙基化十二醇醚磺酸钠〔Ｃ１２Ｈ２５ＯＣ２Ｈ４）３ＳＯ３Ｎａ，简称Ｃ１２ＥＯ３Ｓ〕与十六烷基三甲基溴化铵（ＣＴＡＢ），十二烷基三甲基溴化铵（ＤＤＴＡＢ）复配体系在纯水溶液中的表面活性，计算了１＝１复配体系胶束形成和表面吸附的标准自由能ΔＧ＾０ｍｉｃ、ΔＧ＾０ａｄ，及分子间相互作用参数β＾ｍ、β＾ｓ，揭示了两组分相互作用的强度和混合体系表面相及胶团的组成。     

用MSA作释放剂选择性螯合滴定法测定锆

本法提出测定锆的简易、快速螯合滴定法。向含有锆（Ⅳ）和其它阳离子的溶液中，加入过量的ＥＤＴＡ，在ｐＨＳ～６时以ＸＯ（二甲酚橙）－ＣＰＢ（溴化十六烷基吡啶）为混合指示剂，用Ｚｎ（ＮＯ３）。标准溶液返滴过量的ＥＤＴＡ。然后加入巯基丁二酸（ＭＳＡ）分解Ｚｒ－ＥＤＴＡ螯合物，释放出的ＥＤＴＡ，用Ｚｎ（ＮＯ３）２标准溶液滴定．终点变化更加敏锐．研究了各种离子的干扰．此法已被用于测定锆英石矿、高温耐火涂料中的锆，结果是满意的．     

端环氧基二硅氧烷和端胺基二硅氧烷的合成及固化动力学（I）

合成了１,３－二甲基－１,３－二乙基－１,３－双（３－（２,３－环氧丙氧基）丙基）二硅氧烷（ＴＥＤＳ）和１,３－二甲基－１,３－二乙基－１,３－二胺丙基二硅氧烷（ＴＡＤＳ）,用ＦＴＩＲ和ＤＳＣ对ＴＥＤＳ／ＴＡＤＳ体系的固化反应动力学进行了研究,结果表明,反应对ＴＥＤＳ和ＴＡＤＳ均为一级反应,固化体系的反应活化能在４５－６５ｋＪ／ｍｏｌ,与文献报道的双酚Ａ环氧树脂的反应活化能相一致。     

微米级硫钨酸铵在氢气中的热分解动力学

用ＤＴＡ法和ＸＲＤ法研究了粒度为６３～７４μｍ的硫钨酸铵在氢气中的热分解机理，用Ｋｉｓｓｉｎｇｅｒ法、Ｆｒｅｅｍａｎ－Ｃａｒｏｌ法和Ｃｏａｓｔ－Ｒｅｄｆｅｒｎ法测得硫钨酸铵热分解反应三个阶段的活化能分别为（５３±０．５），（１２７±０．５），（３００±０．８）ｋＪ／ｍｏｌ，反应级数分别为０．８，０．６，１．５．硫钨酸铵在氢气中的热分解分四步进行，即（ＮＨ４）２ＷＳ４·Ｈ２Ｏｓ→（ＮＨ４）２ＷＯ４（ｓ）＋Ｈ２Ｏ（ｇ）→ＷＳ２（ｓ）＋２ＮＨ３（ｇ）＋Ｈ２（ｇ）＋２Ｓ（１）＋Ｈ２Ｏ（ｇ）→ＷＳ２（ｓ）＋２ＮＨ３（ｇ）＋２Ｈ２Ｓ（ｇ）＋Ｈ２Ｏ（ｇ）→ＷＳ２（ｓ）＋Ｗ（ｓ）＋２ＮＨ３（ｇ）＋２Ｈ２Ｓ（ｇ）＋Ｈ２     

表面活性剂和四烷基溴化铵的复配：Ⅱ.四乙基溴化铵对离子型表面活性剂 …

用表面张力法研究了有机电解质四乙基溴化铵（（Ｅｔ）４ＮＢｒ）对离子型表面活性剂十二烷基硫酸钠（ＳＤＳ）和十二烷基三甲基溴化铵（ＤＴＡＢ）在气／液表面吸附行为的影响。表明（Ｅｔ）４ＮＢｒ提高了ＳＤＳ和ＤＴＡＢ降低水溶液表面张力的效率。但（Ｅｔ）４ＮＢｒ仅提高ＤＴＡＢ降低水溶液表面张力的能力,却反而削弱了ＳＤＳ降低水溶液表面张力的能力。通常电解质对离子表面活性剂表面吸附层的影响主要来自与表面活性离子电     

TiO2加入量对高炉渣微晶玻璃析晶的影响

以高炉渣微晶玻璃为研究对象,改变配料中晶核剂TiO2的含量,制得微晶玻璃样品. 以不同的升温速率对样品进行差热分析,根据升温速率和差热分析曲线上的晶化峰温度,采用3种不同的方法计算微晶玻璃样品的析晶活化能. 结果表明,随着TiO2含量的增加,析晶活化能呈现出先减小后增大的趋势,在TiO2的加入量为3.1%时,微晶玻璃的析晶活化能最低,此时拟合出的3种析晶活化能最小值分别为135.7, 143.9, 151.7 kJ/mol. 样品的红外谱图表明,TiO2的含量为3%~4%时析出晶体较多. TiO2含量为3%和4%的样品的X射线衍射图谱表明,样品中析出了以透辉石为主晶相、金红石为次晶相的晶体.     

Nonisothermal crystallization kinetics of carbon nanotubes containing segmented polyurethane elastomer

Nanocomposites of the segmented polyurethane (SPU) elastomer with different concentrations of multiwall carbon nanotubes (MWCNTs) have been prepared. Scanning electron microscopy has been used to visualize the surface morphology and distribution of the nanotubes inside the matrix. Differential scanning calorimetry has been utilized to investigate the effects of MWCNTs on the crystallization characteristics of the SPU by collecting data at four cooling rates namely 5, 10, 15, and 20°C/min in the temperature range between 200°C to ambient. The results reveal that MWCNTs act as effective nucleating agent for crystallization of the hard segment of SPU and advance the onset and peak temperatures of crystallization by 38 and 23°C, respectively. The associated enthalpy and extent of crystallization are also increased by 34%. Different crystallization kinetic parameters have been calculated using both modified Avrami and combined Ozawa‐Avrami models to suggest a three dimensional growth of crystallization of SPU and its nanocomposites. The activation energy has been calculated using Kissinger method, which indicates that activation energy decreases with increasing concentration of MWCNTs. The calorimetric results have further been correlated with thermomechanical analysis and glass transition temperature of the nanocomposites corresponding to soft segment is found to increase by 20°C. POLYM. ENG. SCI., 56:1248–1258, 2016. © 2016 Society of Plastics Engineers     

Crystallization with Variable Temperature: Corrections for the Activation Energy

The Nakamura-Avrami method has been revised to derive reliable solutions for describing the kinetics of crystallization on heating with variable temperature. The corresponding numerical solutions for first-order phase-boundary-controlled growth were computed to evaluate the errors that should be expected when using simple approximate solutions. The relative differences increased as the average dimensionless temperature increased; thus, a method was proposed to obtain correct values for the activation energy and pre-exponential factors. Our analysis of the effects of heating rate on the crystallization peak is consistent with the Kissinger equation, even for dimensionality values of >1. Numerical solutions were also used to demonstrate the validity of the Kissinger equation.     

Isothermal crystallization measurements on poly(ethylene terephthalate) by differential enthalpic analysis

The process of solid-phase crystallization in poly(ethylene terephthalate) has been followed by means of differential enthalpic analysis. Kinetic data for the process has been obtained for isothermal annealing from 100 to 115°C., showing induction times and first-order rate dependence. For the material studied, undrawn polyester filaments, an activation energy of 44 kcal./mole was determined. The technique used provides more direct monitoring of the crystallization phenomenon than that achieved with other methods.     

Some studies on nucleation,crystallization, microstructure and mechanical properties of mica glass-ceramics in the system 0.2BaO·0.8K2O·4MgO·Al2O3·6SiO2·2MgF2

The crystallization, microstructure, microhardness and theoretical machinability have been investigated by DTA, XRD, SEM and Microhardness Indenter of resulting glass-ceramics. Two distinct crystallization exotherms in the DTA curve are observed and resolved. The first peak corresponds to the initial formation of potassium fluorophlogopite and the second is due to the formation of barium fluorophlogopite. The activation energy for precipitation of each crystalline phase has been evaluated, and the crystallization mechanism has been studied. DTA analyses were conducted at different heating rates and the activation energy was determined graphically from Kissinger and Ozawa equation. The average activation energy is calculated as 276 KJ/mol for the first and 366 KJ/mol for the second crystallization peak. The Avrami exponent for first and second crystallization peak temperature determined by Augis and Bennett method is found to be 3 and 3.9, respectively. The results indicate that the growth of mica is a two and three dimensional process, controlled by the crystal-glass interface reaction. The Vicker's hardness decreased steadily at intermediate heat treatment temperature with the formation of barium and potassium fluorophlogopite phase, but the decrease in hardness is more rapid at higher temperature with the development of an interconnected ‘house of cards’ microstructure.     

PE-HD/PE-UHMW共混物的非等温结晶动力学研究

采用差示扫描量热仪研究了超高相对分子质量聚乙烯（PE-UHMW）对高密度聚乙烯（PE-HD）非等温结晶行为的影响。通过Jeziorny法和莫志深法研究了PE-UHMW/PE-HD共混物的非等温结晶动力学,并利用Kissinger方程和Takhor法计算了体系的非等温结晶活化能。结果表明,PE-UHMW是PE-HD的一种有效成核剂,提供了更多的活化晶核,起到了异相成核的作用;添加PE-UHMW后,PE-HD的结晶起始温度（To）、结晶峰值温度（Tp）和结晶速率均提高;当PE-UHMW含量为10 %（质量分数,下同）时,共混物结晶的活化能最小,结晶速率最大。     

Dependence of Crystallization Behavior on Particle Size in Barium Strontium Titanate Glass‐Ceramics

Differential thermal analysis studies on the crystallization kinetics and phase developments of barium strontium titanate glass‐ceramics have been performed for a series of glass particles with different particle sizes. The crystallization behavior was deduced to be influenced strongly by the particle size of the glass samples. These studies have revealed the initial formation at lower temperatures of metastable fresnoite Ba₂TiSi₂O₈ (BTS) phase followed by its transformation at higher temperatures to feldspar BaAl₂Si₂O₈ (BAS) and perovskite (Ba,Sr)TiO₃ (BST) phases. The metastable BTS phase was proved to crystallize predominately by surface crystallization while the feldspar BAS phase showed significant evidence of internal crystallization. And for the perovskite BST phase, crystallization mechanism changes from surface to internal type at a critical particle size of 75 μm. In addition, activation energy and the Avrami parameter for crystallization have been determined for the three phases by the employment of glass samples with two typical particle sizes.     

Nonisothermal and isothermal crystallization kinetics of nylon‐12

The isothermal and nonisothermal crystallization behavior of Nylon 12 was investigated using differential scanning calorimetry (DSC). An Avrami analysis was used to study the isothermal crystallization kinetics of Nylon 12, the Avrami exponent (n) determined and its relevance to crystal growth discussed and an activation energy for the process evaluated using an Arrhenius type expression. The Lauritzen and Hoffman analysis was used to examine the spherulitic growth process of the primary crystallization stage of Nylon 12. The surface‐free energy and work of chain folding were calculated using a procedure reported by Hoffmann and the work of chain folding per molecular fold (σ) and chain stiffness of Nylon 12 (q) was calculated and compared to values reported for Nylons 6,6 and 11. The Jeziorny modification of the Avrami analysis, Cazé and Chuah average Avrami parameter methods and Ozawa equation were used in an attempt to model the nonisothermal crystallization kinetics of Nylon 12. A combined Avrami and Ozawa treatment, described by Liu, was used to more accurately model the nonisothermal crystallization kinetics of Nylon 12. The activation energy for nonisothermal crystallization processes was determined using the Kissinger method for Nylon 12 and compared with values reported previously for Nylon 6,6 and Nylon 11. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Nonisothermal crystallization and morphology of crystallites of polyamide 66 and copolyamide 66 containing 2‐carboxyethyl phenyl phosphinic acid

Flame‐retardant polyamide 66 with a 10% mass fraction of 2‐carboxyethyl phenyl phosphinic acid (CEPPA) hexamethylene diamine salt (PA66‐10) was fabricated in our previous study. In this study, the nonisothermal crystallization kinetics of pure polyamide 66 (PA66‐0) and PA66‐10 were measured by differential scanning calorimetry, and the data obtained were analyzed, and we calculated the average Avrami exponent (n) and used the Jeziorny, Mo, and Kissinger methods. The results from all of these methods show that the crystallization mechanism of PA66‐0 mainly consisted of three stages, whereas PA66‐10 mainly consisted of two stages. At the prime stage, both PA66‐0 and PA66‐10 may have had the same crystallization mechanism. When the cooling rates were 15 and 20°C/min, the approximate n suggested that the growth form of the spherulite mode in PA66‐0 may have been complicated, whereas PA66‐10 may have had a one‐dimensional, two‐dimensional space‐extension, circular, diffusion controlled growth. The crystallization activation energies were determined to be 183.2 and 301 kJ/mol for PA66‐0 and PA66‐10, respectively, by the Kissinger method. To further study the influence of the addition of CEPPA on the crystallization behaviors of PA66‐0, the spherulitic morphologies were examined by polarized light microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41790.     

Kinetics of isothermal and nonisothermal crystallization of nylon 1313

The crystallization process of a new polyamide, nylon 1313, from the melt has been thoroughly investigated under isothermal and nonisothermal conditions. During isothermal crystallization, relative crystallinity develops in accordance with the Avrami equation with the exponent n ≈ 2 based on DSC analysis. Under nonisothermal conditions, several different analysis methods were used to elucidate the crystallization process. The Avrami exponent n is greater in the isothermal crystallization process, indicating that the mode of nucleation and the growth of the nonisothermal crystallization for nylon 1313 are more complicated, and that the nucleation mode might include both homogeneous and heterogeneous nucleation simultaneously. The calculated activation energy is 214.25 kJ/mol for isothermal crystallization by Arrhenius form and 135.1 kJ/mol for nonisothermal crystallization by Kissinger method, respectively. In addition, the crystallization ability of nylon 1313 was assessed by using the kinetic crystallizability parameters G. Based on this parameter, the crystallizability of many different polymers was compared theoretically. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1415–1422, 2007