阻燃剂硼酸锌的分析测定

介绍了采用直接络合滴定法测定硼酸锌中氧化锌和三氧化二硼的条件和方法，本法测定结果与传统分析方法测定结果吻合，终点变色每锐，重现性好，具有快速，简便，准确等优点。     

硼酸锌中硼含量的测定

<正> 硼酸锌系无机添加型无毒阻燃剂,是美国70年代初开发的专利产品。由于它热稳定性高、粒度细、密度小、着色强度低,有效的抑烟作用和优良的协同效应,故国内外已广泛应用于各种工程塑料、橡胶制品、涂料和纤维织物的阻燃处理。国内目前还没有统一的硼酸锌检测标准,分析方法不甚完善,为提高该产品化学分析的准确度,我们对硼酸锌中     

熔块釉中三氧化二硼的测定

用NaOH熔融样品，向标准溶液中加入同样量的KOH基体，建立工作曲线，试样酸化后，直接用ICP－AES法测定。     

硼酸锌中硼的测定

介绍了测定硼酸锌中硼的沉淀分离法、离子交换法、EDTA络合掩蔽法、8—羟基喹啉络合掩蔽法。     

过渡金属硼酸盐中金属氧化物和三氧化二硼含量的测定

过渡金属硼酸盐中金属氧化物和三氧化二硼的测定采用常规方法会因沉淀物的干扰使测定结果偏高,若采用直接络合法测定比传统方法灵敏度高,重现性好,结果精确无误。     

硼酸锌中三氧化二硼含量的测定

一、前言对于硼酸锌中三氧化二硼的测定,由于锌干扰了硼的测定,因此必须预先分离,分离方法可采用蒸馏分离法、沉淀分离法和离子交换法。由于蒸馏分离法操作复杂,应用不广泛,本实验从略。仅对沉淀分离法和离子交换分离法进行探讨。二、原理1.沉淀法硼酸锌溶解在酸性溶液中,加入过量CaCO_3,使溶液中Zn~(++)全部转化为ZnCO_3沉淀(SPZnCO_3=1.0×10~(-10)),然后采用甘露醇法测定溶液中三氧化二硼含量。     

硼硅玻璃中三氧化二硼的前处理方法研究

为了提高三氧化二硼检测结果准确性,降低分析成本,实现高效、准确的检测,探讨了样品前处理对检测结果的影响,介绍了硼硅玻璃包装材料利用酸碱滴定法测定三氧化二硼含量方法,分析和探讨了样品粒度、坩埚、熔融试剂、样品量等因素对检测结果的影响,通过对三氧化二硼含量测定结果比较,表明降低样品量、样品经八号药典筛处理、镍坩埚氢氧化钠熔样,可节约成本,提高工作效率和检测结果准确性。     

含硼固体推进剂燃烧残渣中三氧化二硼和碳含量测定及燃烧机理研究

为了研究含硼富燃料固体推进剂燃烧机理,对3种配方的不同批次含硼富燃料固体推进剂在不同压强的燃速进行了测试,利用化学分析法对其燃烧残渣中B2O3和C含量也进行了测定。结果表明,硼粒子表面的B2O3延缓了硼粒子的进一步燃烧,因此残渣中B2O3含量较低;随着氮气压强增高,残渣中B2O3含量降低,而C含量、B2O3与C总含量升高;随着推进剂配方中镁含量增高,残渣中B2O3含量降低,C含量先升后降,B2O3和C总含量则降低。     

分光光度法测定98%工业硫酸中三氧化二氮的方法改进

改进了测定９８％工业硫酸中的三氧化二氮含量的分光光度法。用Ｈ２ＳＯ代替ＨＡＣ中和过量的ＮａＯＨ和分析操作更容易。     

氧化铁含量的测定

对测定氧化铁含量的方法进行了研究。通过络合法和氧化还原滴定法的对比试验，发现重铬酸钾氧化的滴定法可以获得稳定的分析结果；讨论了该分析方法的测定原理并确定了相应的分析条件及精密度。     

浅析中碱玻纤配合料中纯碱测定指示剂的调整

通过溴甲酚绿-甲基红指示剂和甲基橙指示剂分别在基准物质和配合料中的滴定结果的分析对比,论证了配合料中纯碱测定所用指示剂——甲基橙指示剂调整为溴甲酚绿-甲基红指示剂的可行性,提高了试验的准确性和精确度。     

溶剂热改性法制备亚微米级低水硼酸锌

以氧化锌和硼酸为原料通过溶剂热改性法制备了亚微米级低水硼酸锌(2ZnO.3B2O3.3H2O),利用化学分析、XRD、SEM和IR等手段对产物进行了表征。结果表明:溶剂热改性法可以制得团聚少,分散性好,结晶程度高,粒径0.2~0.4μm的亚微米级低水硼酸锌(2ZnO.3B2O3.3H2O)颗粒;TG分析表明,合成样品的开始脱水温度在290℃左右。并对反应机理进行了简单探讨。     

Use of zinc borate as the third component of a traditional brominated flame retardant system in acrylonitrile butadiene styrene

Because zinc borate is an effective smoke suppressant and cheaper than antimony trioxide, the main aim of this study was to investigate usability of zinc borate as the third component of a traditional binary Br/Sb₂O₃ system in acrylonitrile butadiene styrene. Limiting oxygen index, UL‐94, and mass loss cone calorimeter studies indicated that almost all flame retardancy parameters were kept when certain percentages of antimony trioxide were replaced with zinc borate. Residue analysis revealed that the predominant flame retardancy mechanism of the traditional system was gas phase action, whereas zinc borate contributes especially in the condensed phase action by forming thicker and stronger char layer. Copyright © 2012 John Wiley & Sons, Ltd.     

硼酸锌在膨胀型无卤阻燃ABS中的协同作用

采用熔融共混法制备了丙烯腈-丁二烯-苯乙烯共聚物(ABS)/膨胀型阻燃剂(IFR)/硼酸锌(ZB)无卤阻燃复合材料。利用热重分析仪、氧指数测定仪、扫描电子显微镜等研究了ZB对复合材料热失重行为、阻燃性能、微观结构及力学、加工性能的影响。较低含量的ZB与IFR存在较好的阻燃协同作用,且ZB可促进IFR成炭,使ABS/IFR复合材料的氧指数及其残炭量分别由未加ZB时的27.4%、21.29%提高到30.1%和23.05%。ZB的加入能够提高ABS/IFR复合材料的弯曲性能和加工性能,但对复合材料的冲击、拉伸性能产生了不利影响。     

Cu基ZnO薄膜紫外光催化降解水中有机污染物

利用Cu基ZnO薄膜紫外光催化降解水体中的有机污染物是一项非常有前景的水处理技术,本文利用电化学沉积方法,在锌盐的水溶液中沉积制备Cu基ZnO薄膜,并以较难降解的偶氮类有色化合物甲基橙是为例,紫外光照射下,用制备好的Cu基ZnO薄膜降解水中甲基橙.结果表明有很好的催化降解效能.该技术还没有得到广泛应用,有待于进一步完善...     

浅谈混合碱液实验教学中如何引导学生理论与实验相结合

混合碱液测定实验是经典分析化学基础实验酸碱滴定中一个较难完成的实验,该实验存在两个滴定终点,实验需要连续滴定完成。引导学生通过理论推理和计算判断化学计量点的酸碱性,从而选择指示剂,由于第一化学计量点是碱性,所以选择酚酞做指示剂,第二化学计量点显酸性,所以选择甲基橙做指示剂。由于本实验是连续滴定,第一滴定终点的准确度直接影响第二滴定终点的准确度和精密度。通过引导学生理论与实验相结合,显著提高了实验的的成功率和学生的积极性。     

选择性络合滴定法测定伪劣钛白粉中二氧化钛含量

不法企业在钛白粉中常掺入碳酸钙、立德粉、高岭土等违法添加物。针对此现状,建立了钛含量的选择性络合滴定法。方法采用浓硫酸、硫酸铵分解试料,丙三醇作为TiO2+的水解抑制剂,试样溶液pH为2.0～4.0,用过量的乙二胺四乙酸二钠（EDTA）络合TiO2+及其他金属离子,建立以二甲酚橙（XO）-甲基百里酚蓝（MTB）-十二烷基硫酸钠（SDS）为混合指示剂三元体系,用氯化锌标准溶液回滴过量的EDTA,酒石酸钾钠选择性分解TiO-EDTA,再用氯化锌标准溶液滴定释放的EDTA。该方法的加标回收率为98.78%～100.18%、相对标准偏差（RSD）为0.10%～ 0.78%。该方法操作简便,终点变化清晰且敏锐,适用于伪劣钛白粉中二氧化钛含量的测定。     

A novel route to superhard nanocrystalline cubic boron nitride: Emulsion detonation and high-pressure high-temperature transformation-assisted consolidation

Synthesizing bulk nanocrystalline materials is challenging since grain growth should be suppressed whereas densification promoted. Here, we demonstrate a novel route to synthesize superhard bulk nanocrystalline cubic boron nitride (cBN), which combines the use of emulsion detonation and high-pressure high-temperature transformation-assisted consolidation. The emulsion detonation process activates BN to possess unique structure and chemistry, i.e. wurtzitic BN nanograins in hexagonal BN matrix with enhanced structural disordering and oxygen impurity, a combination that enhances the nucleation rate of cBN and its densification leading to the formation of bulk nanocrystalline cBN at reduced conditions. The cBN, synthesized at 7.5 GPa and 1800 °C, displayed Vickers hardness values of 50?62 GPa for 5?20 N loads. The findings in the study suggest a feasible solution to synthesize bulk nanocrystalline cBN in a more scalable way, while also providing design insights on how to refine grain growth while enhancing densification to synthesize bulk nanocrystalline materials.     

A novel approach to the synthesis of high 1,4-telechelic polybutadienes by an anionic route

Evidence is given that the presence of a sterically hindered Lewis acid during the anionic polymerization of butadiene in tetrahydrofuran results in a product with enhanced 1,4-content. Trimesityl boron was the Lewis acid principally employed and its influence allowed the 1,4-content to be raised to 50%. A relatively slow but competing proton abstraction reaction with the propagating polybutadienyl anion was, however, observed and alternative more specific additives are suggested.     

A novel kinetic approach to crystallization mechanisms in polymers

Kinetics of polymer crystallization is capable of modeling the polymer crystallization processes by revealing their mechanisms. Although complexities of polymer crystallization processes are familiar, a generalized approach for their kinetic modeling has not yet been suggested. This paper presents a concise review of the pre-existing kinetic approaches to polymer crystallization, including their pros and cons, putting a special emphasis on the necessity of approaches to polymer crystallization. A systematic and advanced approach comprising an innovative kinetic framework to model polymer crystallization processes is put forward using Hoffman-Lauritzen theory. Kinetic functions are developed for predicting the crystallization mechanisms of simple as well as complicated polymer crystallization processes. The suggested kinetic approach is experimentally justified by its effective applications to non-isothermal glass and melt crystallization of poly(ethylene 2,5-furandicarboxylate). An account of the soundness of the proposed kinetic approach and its prospective applications are also discussed.