钴、锰、铅的邻苯二甲酸配合物的合成、表征及热分析

用流变相反应法合成了二水合邻苯二甲酸钴(Ⅱ)、邻苯二甲酸锰(Ⅱ)、邻苯二甲酸铅(Ⅱ),通过元素分析、红外光谱、TG、DTG和DSC研究了它们在氮气气氛中的热分解过程。二水合邻苯二甲酸钴在氮气中的热分解分为两个过程:第1步失去结晶水形成无水盐,第2步无水盐分解为氧化钴、二氧化碳和有机化合物;邻苯二甲酸锰在氮气中一步分解生成氧化锰和有机化合物;邻苯二甲酸铅在氮气中的热分解过程分为两个阶段:第1步邻苯二甲酸铅分解生成碳酸铅和有机化合物,第二步碳酸铅继续分解生成氧化铅和二氧化碳;三种配合物在氮气中热分解生成的有机化合物成分比较复杂,主要成分是邻苯二甲酸酐、9,10-蒽醌等。     

DL-2-萘普生热分解过程和非等温热分解动力学研究

用热重-差热联用分析(DTA-TGA)技术和差动扫描(DSC)技术研究了DL-2-萘普生在空气中的热分解过程和非等温热分解机理及动力学.DTA-TGA分析表明DL-2-萘普生在((250.722～296.87)±4.88)℃之间发生热分解反应,结合DSC分析表明DL-2-萘普生的熔点为(158.16±0.6)℃,熔融热...     

印尼褐煤的热分解特性研究

采用热重分析和热解实验对印尼褐煤的热分解特性进行研究,探讨了印尼褐煤的热解机理、升温速率和热解终止温度对热解过程的影响.结果表明,印尼褐煤的热失重过程包括水分蒸发、挥发分析出和焦炭形成三个阶段;在温度低于300℃时,印尼褐煤以水分蒸发和脱除吸附小分子气体为主,300℃时开始微热解反应,400℃时热分解反应剧烈.在同一热解温度条件下,升温速率为10K/min～20K/min的慢速升温热解过程中,焦油产率维持在8.5%(质量分数)附近,升温速率对热解产物产率的影响较小;在400℃～600℃的低温热解范围内,热解终止温度对焦油产率影响较小,但热解气体产率随热解终止温度的增大而增大,而半焦产率却随之降低.     

生漆提取剩余物热解动力学研究

利用热重分析(TGA)对生漆提取剩余物进行热解动力学研究。采用Kissinger, Friedman, Flynn-Wall-Ozawa(FWO)、Kissingr-Akahira-Sunose(KAS)和Coats-Redfern方法来估算生漆提取剩余物分解过程的活化能。结果表明：生漆提取剩余物热分解阶段为两个阶段,第一阶段最大热失重速率温度为293℃,第二阶段最大热失重速率温度453℃。推断生漆提取剩余物热分解过程对应的机理函数为21号,即Prout Tompkins方程(催化,分支随机成核),其机制函数的积分形式：■。求解得E_a=275.70KJ/mol, lnA=46.69,A=1.89×10²⁰min^-1,且具有较长的贮存期。     

氟哌酸的热分解动力学及其寿命的研究

采用非等温热重技术研究了氟哌酸的热分解动力学，运用Coats-Redfern(CR)法，Horowitz-Metzger(HM)法，Madhusudanan-Krishnan-Ninan(MKN）法和Kissinger法计算了氟哌酸第二步热分解过程的动力学参数如活化能E，指前因子A等。同时用等温热重法得到了失重10％为寿终指标的寿命方程lgc=7786.8/T-20.60。     

松木脱脂行为的热重研究

本文应用热重分析法研究了松木在10℃.m in-1升温速率下,30~700℃的热分解过程,分析了每个阶段的化学物理变化,并比较了干燥脱脂和丙酮脱脂后松木的热解行为,找出高温脱脂的最佳温度为180~200℃。利用松木热重分析曲线求得松木热解脱脂反应为一级反应,表观活化能为93.18KJ.mol-1,这些数据可为松木的脱脂与防火研究提供参考。     

四氧化三铁存在下LDPE热分解动力学研究

采用不同升温速率(51,01,5,20℃/min),在四氧化三铁存在下,研究了低密度聚乙烯(LDPE)在氮气氛围中的热分解动力学。结果表明,四氧化三铁存在下,LDPE的热分解只有一个过程,为一级反应,用5种不同的动力学分析方法(即Kissinger方法、Freeman-Carroll方法、Van Krevelen方法、Coats-Redfern方法和Horowitz-Metzger方法)计算了复合材料的热分解动力学参数5,种动力学分析结果均显示,与纯聚乙烯相比,四氧化三铁存在下,聚乙烯的活化能有所提高,而且在实验添加范围内,聚乙烯活化能的增加与四氧化三铁的含量成正比,表明添加四氧化三铁会提高聚乙烯的热分解温度,四氧化三铁能提高聚乙烯的热稳定性能。     

热重-红外联用法研究液晶聚合物的热解行为及其逸出气体组成

采用热重-红外(TGA-FTIR)联用技术研究液晶聚合物(LCP)的热分解行为,研究不同升温速率(10、20、30、40、50℃/min)对LCP热稳定性的影响,同时对LCP的逸出气体组成进行分析。结果表明:LCP受热分解过程主要为一个失重阶段,LCP组分受热后,分子链断裂,降解成三聚体、二聚体、单体等化合物,有些化合物裂解成烃类物质生成CO2逸出。升温速率对LCP热分解过程的影响主要表现在最大失重速率温度(T_m)和最大失重速率(D_m)上,随着升温速率的增加,D_m增加,T_m升高。     

一种使用废铅膏制备高纯度乙酸铅和纳米铅粉的方法

正本发明涉及高纯乙酸铅和纳米铅粉的制备方法,尤其是涉及一种采用废铅酸电池的废铅膏制备高纯乙酸铅和纳米铅粉的方法。其步骤为:将废铅膏加到有脱硫剂的溶液中脱硫后进行固液分离,得到脱硫铅膏;在得到的脱硫铅膏中加入乙酸溶液和作为还原剂的溶液,得到可溶性含铅酸性溶液;将得到的可溶性含铅酸性溶液加入冰乙酸进行重结晶提纯,获得高纯度三水合乙酸铅晶体和冰乙酸溶液。把高纯度乙酸铅晶体置于管式炉或马弗炉中焙烧,获得纳米铅粉。     

聚酰胺固化环氧树脂的热分解动力学研究

利用热重分析(TG)采用不同升温速率(10,15,20,25℃/min)分别在空气和氮气气氛下对聚酰胺固化环氧树脂热稳定性进行了研究.采用Coats-Redfem和Ozawa热分析处理动力学数据的方法,计算了环氧树脂热分解反应活化能E、反应级数n及频率因子A.求得空气气氛下5%～30%的失重率下反应表观活化能在70.3...     

Comparison of different sintering aids in cold sinter-assisted densification of lead zirconate titanate

Ceramics such as lead zirconate titanate (PZT) tend to dissolve incongruently, and thus pose a challenge in the cold sintering process. Moist lead nitrate has previously been shown to enable a cold sinter-assisted densification of PZT by a viscous phase sintering mechanism. In this paper, lead acetate trihydrate is demonstrated to lower the required temperature of the cold sintering step to 200°C. This densification process was described as a two-step process: cold sintering of PZT with lead acetate trihydrate and post-annealing the as-cold sintered PZT ceramics. Unlike in the case of lead nitrate, PZT densification with lead acetate trihydrate occurs by a liquid phase assisted sintering mechanism, leading to an as-cold sintered relative density of 84% at 200°C. After performing a post-anneal step at 900°C, >97% relative densities were achieved in samples that were cold sintered with lead acetate trihydrate. This step not only densified PZT but also refined the grain boundaries. In the post-annealed samples, the room-temperature relative permittivity at 100 Hz was ~1600, slightly higher than that reported in samples that used lead nitrate as a sintering aid; the loss tangent was about 3.8%. For measurements at 10 Hz, the remanent polarization in both cases was ~28 µC/cm². Both Rayleigh analysis and aging studies showed that a higher irreversible contribution to the permittivity exists in samples that used lead nitrate as a cold sintering aid.     

金属有机物热分解法合成的PZT纳米晶粉末的表征

以醋酸铅、庚酸氧锆和钛酸丁酯为原料,采用金属有机物热分解法成功地制备了ＰＺＴ钠米晶粉末,并通过ＸＲＤ,ＦＴＩＲ,ＤＴＡ,Ｒａｍａｎ,ＴＥＭ等方法对钠米粉末的结构进行了表征。粉末粒径为２０－４０ｎｍ,大小均匀,颗粒呈球形,且分散性好。研究结果显示,金属有机物热分解法是制备ＰＺＴ或其它纳米粉末的一种很有前途的方法。     

Flame retardancy of some ethylene–vinyl acetate copolymer‐based formulations

The combustion behaviour and thermal decomposition of ethylene–vinyl acetate copolymer (EVA) (26 wt% vinyl acetate content) formulations containing alumina trihydrate, ammonium polyphosphate, melamine, pentaerythritol and their co‐mixtures, were studied using cone calorimetry and thermogravimetric analysis. Formulations containing ammonium polyphosphate burned with the formation of intumescent carbonaceous chars, with EVA acting as a carbonization agent. EVA materials containing ammonium polyphosphate (20 wt%), with a sufficient amount of alumina trihydrate or melamine, were superior to the non‐intumescent alumina trihydrate and melamine containing formulations in terms of the heat release rate, mass loss rate and smoke production. Melamine showed some smoke suppressant effect and significant CO reducing properties. However, the melamine–EVA and melamine–alumina trihydrate–EVA showed a very high heat release rate. Thermogravimetric studies showed that oxygen played a favourable role in enhancing the char formation by encouraging active participation of the polymer matrix in the interaction with polyphosphoric acid. Copyright © 2000 John Wiley & Sons Ltd.     

高钙钒渣焙烧过程中硅酸盐矿物变化特征研究

作为钒渣体系的重要组成部分,查明硅酸盐矿物在焙烧阶段的变化特征有助于更好掌握钒渣体系在焙烧过程的演变规律,对指导焙烧工艺的改进具有重要意义。文章综合应用X射线衍射分析仪、矿物分析仪、扫描电镜以及能谱仪等技术手段对高钙钒渣焙烧阶段主要硅酸盐矿物的变化特征进行分析,结果表明:铁橄榄石的氧化分解温度区间为334~850 ℃,分解初期颗粒内外形成非晶态石英,随温度上升,铁橄榄石颗粒外缘出现逐渐加厚的氧化铁边直至颗粒完全分解,其分解产物为石英和氧化铁;钙铁辉石的氧化分解温度区间为334~850 ℃,分解初期同样以颗粒内外形成非晶态石英为标志,随温度上升,钙铁辉石颗粒外缘出现钒酸钙环带和氧化铁直至颗粒完全分解,其分解产物主要为石英、钒酸钙和氧化铁;硅酸二钙的反应温度区间为640~850 ℃,反应初期以颗粒外缘出现钒酸钙环带为标志,随温度升高,硅酸二钙逐渐分解,其分解产物主要为钒酸钙、石英和氧化铁。     

铜铟硫纳米粒子的溶剂热合成及表征

采用溶剂热法,以二乙基二硫代氨基甲酸铜和二乙基二硫代氨基甲酸铟配合物为前体,油胺为配体,合成了铜铟硫纳米粒子。研究了配体与前体的配比、反应时间、反应温度以及添加剂对产物的影响,采用XRD、SEM等测试方法对产物进行了表征。结果表明,在配体和铜的物质的量比为5∶1,180℃反应,反应时间为8 h,能够得到具有较好的粒度和晶度的铜铟硫纳米粒子。     

纳米氢氧化铝填充LDPE/EVA的力学和阻燃性能

对纳米氢氧化铝（CG-ATH）在低密度聚乙烯/乙烯-醋酸乙烯酯共聚物体系中(low density polyethylene /ethylene vinyl acetate copolymer,简称LDPE/EVA),填充量对力学性质和阻燃性质的影响进行了研究.通过力学性能测试和SEM分析表明,随着CG-ATH填充量的增加,树脂体系的断裂伸长率急剧下降,而其拉伸强度则呈先下降后上升的趋势,当CG-ATH的填充量为60%时,其拉伸强度达12.5 MPa.通过燃烧性能测试、TG和DSC分析表明,CG-ATH的添加能够提高树脂体系的分解温度,增加结炭率,显著提高极限氧指数.通过综合分析,得到填充量为60%时,能够达到树脂体系力学性能与燃烧性能的最佳状态.     

氧化锌/碳复合材料的合成、表征及吸波性能研究

本文先以二水合醋酸锌和氢氧化钠为原料,得到了氧化锌微晶;以合成的氧化锌为前驱物,葡萄糖为碳源,由水热法合成了产物氧化锌/碳(ZnO/C)复合材料。用X射线衍射(XRD),拉曼光谱(RM),扫描电镜(SEM),透射电镜(TEM),热重分析(TG)等,对产物进行了表征,讨论了不同反应条件(添加剂,时间,溶剂)对合成氧化锌/碳微晶的影响,并对产物的微波性能进行了测试。结果表明,所得产物为氧化锌/碳,呈棒状形貌,热稳定性好,并具有优异的吸波性能。在频率为17GHz时,3mm厚度的产物微波吸收达到-12dB。     

Combustion products of lead stabilizers: Dibasic lead phthalate

The volatile products of combustion of dibasic lead phthalate in air were found to be complex and unanticipated. In addition to phthalic anhydride and water, decomposition products anticipated from TGA studies, actual combustion yields salicylic acid, apparently from decarbonylation. The presence of basic lead acetate, from acetic acid catalysis in the preparation of dibasic lead phthalate, leads to minor amounts of dehydroacetic acid and 2‐hydroxyacetophenone.     

The effect of CuO coatings on the electrokinetic properties of stone wool fibres determined by streaming potential measurements

Commercial stone wool fibres were modified with copper(II) oxide coatings. This oxide is widely used in processes of surface modification for filter materials to improve its bacterial retention. The microorganisms are already susceptible to low concentrations of copper in contrast to humans for which copper is an inert material in the concentration range. Additionally, the coatings changed the electrokinetic properties of the fibres. As a result, the isoelectric point (IEP) of the untreated fibres was shifted from acidic towards a more basic pH range. A positive or no charge on the surface of the fibres allows them to be a substrate for the positively charged adsorbents of negatively charged waterborne contaminants with the use of electrostatic adsorption. The coatings were prepared by dip coating with the use of two different coating precursors: the aqueous suspension of CuO nanoparticles and aqueous solutions of copper(II) nitrate trihydrate or copper(II) acetate or a mixture of thereof. The zeta potential of the modified fibres was determined by a streaming potential method. The adhesion of the coatings was tested by flushing and ultrasonication of the modified fibres. The isoelectric point of the fibres was shifted towards a more basic pH range for all precursors with the largest impact of the copper(II) nitrate trihydrate precursor. This coating changed the IEP of the fibres from 4.1 to 8.3 pH value. The highest calculated coverage of the coatings was in the range of 54% and was obtained by using copper(II) nitrate trihydrate/CuO nanoparticles precursor. Although, we do not predict such modified fibres to act as a standalone water filter, we believe they have the potential to be an excellent support material for active adsorbents.     

苯甲酸镍的流变相法合成及热分解机理研究

用流变相反应法合成了苯甲酸镍,通过元素分析、红外光谱确定了组成,用热重分析(TG)和差热分析(DTA)研究了它在氮气气氛中的热分解过程,并用红外光谱、质谱、X-射线衍射表征了热分解产物。