State primary standard of unit of mass fraction and unit of mass concentration of moisture in solid substances and solid fabricated materials

The structure of the state primary standard of the unit of mass fraction of moisture and the unit of mass concentration of moisture in solid substances and solid fabricated materials is considered and the metrological characteristics of these units are presented.     

Creating Reference Standards for the Implementation of the State Verification Scheme for Water Content Measurement

Measurement Techniques - The results of the development of methods for the transfer of units of water content in solid and liquid substances and materials are presented. Four types of comparison...     

Stofftransport durch polymere und anorganische Schichten

Polymeric materials are to be found in an increasing number of applications. In many areas, however, their high permeability for substances such as gases or water vapour creates problems. Traditionally, additional barrier layers are deposited onto the polymeric substrates as a permeation barrier, i.e. as a barrier against the transport of substances. Typically, polymeric layers are deposited from solution in atmospheric pressure, inorganic layers in vacuum processes. Highest barrier properties can be achieved via multi layer systems from inorganic and organic layers. This article describes basic principles of the permeation of substances through layer systems, highlights the differences of the substance transport through polymeric materials and inorganic layers and gives consequences for the production of materials with high and ultra‐high barrier properties, on the basis of polymeric substrates     

Sorption of water vapor by capillary-porous substances in relation to temperature

Sorption of water vapor by typical capillary-porous substances in relation to temperature is examined. The data are used to calculate the temperature dependence of the chemical potential and some coefficients of mass transfer for the hygroscopic state of these substances.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 1, pp. 67–71, January, 1969.     

大豆蛋白基生物降解材料研究进展

大豆蛋白材料的改性方法主要有物理改性、化学改性、酶法改性以及纳米共混改性等。对大豆蛋白材料的性能改善研究主要集中于薄膜材料的成膜性能、机械性能、吸水性能、透光性能、阻气性能和水蒸气透过性能、生物降解性能等方面。大豆蛋白基生物降解材料多被用作制备可食性薄膜,应用于果蔬的涂抹保鲜及部分食品的内包装;改性后的大豆蛋白可作为营养保健物质用作生物材料及生物医用材料。大豆蛋白基生物降解材料未来的发展方向主要为降低成本及增强性能等研究。     

Assessment of removal of components containing hazardous substances from small WEEE in Austria

Minimum treatment requirements for waste electrical and electronic equipment (WEEE) established by Directive 2002/96/EC provide for the removal of specific components containing hazardous substances. To date, no comparative analysis of removal rates has been undertaken. The present paper examines the state of de-pollution of sWEEE in Austrian treatment plants. The mass of selected components removed and the corresponding mass of hazardous substances is compared to estimated values for sWEEE input material. The results obtained reveal that components are only partly removed, featuring a high variation between components and plants assessed. The overall rate of removal ranged from 72% of the estimated value for batteries to 21% of the estimated value for liquid crystal panels. This implies the forwarding of substantial quantities of hazardous substances to mechanical treatment processes, particularly relevant in terms of dispersion of pollutants. Furthermore, easily releasable pollutants, such as Hg from LCD-backlights, Cd from batteries or highly contaminated dust in general, pose substantial health risks for plant workers. Low removal rates of printed circuit boards, batteries and toner cartridges also lead to a reduction in quantities of valuable recyclable materials (precious metals, plastics).     

Identification of archaeological adhesives using direct inlet electron ionization mass spectrometry

Adhesives made from natural substances such as resins, tars, and waxes are found during excavations on archaeological sites dating back to prehistoric periods. Until now, their analysis was mainly performed by gas chromatography, possibly coupled to mass spectrometry, after extraction, purification, and derivatization of the samples. To minimize sampling and sample preparation of ancient organic remains, which are often preserved in tiny amounts, we have directly analyzed archaeological samples from Bronze and Iron Age periods by direct inlet electron ionization mass spectrometry. A series of contemporary natural and synthetic substances, including pine and pistacia resins, birch bark tar, beeswax, and plant oils, possibly used for adhesive fabrication during ancient times, was also investigated with the same technique as reference materials. Despite the complexity of their chemical composition, pine resin and birch bark tar were clearly identified in archaeological samples. Furthermore, mass spectrometry has been shown to be efficient for the identification of glues made of a mixture of beeswax, presenting a series of mass spectral peaks assigned to long-chain esters, and birch bark tar, whose mass spectrum presents characteristic peaks of lupane compounds. The intentional mixing of birch bark tar and beeswax during prehistory is reported here for the first time.     

Electrical treeing in solid polymeric insulation

Polymeric materials are gradually replacing naturally occurring substances for insulators. However their high electrical strength and good mechanical and thermal properties are degraded by the occurrence of water and electrical treeing. The article describes the nature of the forms of electrical treeing and reviews the theories of their formation, their inhibition and their detection     

淀粉基食品包装膜材料的研究进展

目的将淀粉应用于绿色包装领域,开发出具有良好生物降解性的淀粉基食品包装膜材料。方法综述淀粉种类、增塑剂、多糖、脂质及类脂物质、蛋白质、交联剂、无机物和活性物质等对淀粉膜性能的影响。结果在淀粉膜的制备中,选用高直链淀粉含量的淀粉,并加入增塑剂和交联剂可以改善淀粉膜的力学性能,降低薄膜的水蒸气渗透性;淀粉与多糖或蛋白质复合后,不同成膜材料优势互补,薄膜性能会得到改善,加入脂质或类脂物质可改善薄膜的阻水性。结论随着研究的深入,淀粉基食品包装膜材料在很多领域都会有广阔的应用前景。     

高分子材料纤维素醚类衍生物在缓释制剂辅料中的应用

药用辅料是药物制剂的基础材料和重要组成部分,缓释制剂中起缓释作用的辅料多为高分子化合物.综述了高分子材料纤维素醚类衍生物中羧甲基纤维素钠、甲基纤维素、乙基纤维素、羟丙基甲基纤维素和羟丙基纤维素等作为药用辅料在缓释制剂中的应用,并展望了其应用前景.     

静态顶空–气相色谱质谱联用结合感官评价分析3种胶黏剂中的气味物质

目的 探究纸包装材料用胶黏剂中挥发性气味物质及其影响。方法 选择10名感官评价员对3种胶黏剂样品的气味强度进行嗅辨分析,使用顶空–气相色谱质谱法(Headspace-Gas Chromatography-Mass Spectrometry, HS-GC-MS)采集挥发性化合物数据,利用MS–DIAL软件解卷积、NIST质谱库和保留指数实现对物质的定性分析,计算各化合物的相对峰面积含量和相对气味活性值(Relative Odour Activity Value, ROAV),用于确定样品气味特征的关键贡献物质及其影响。结果 3种胶黏剂样品的感官影响差异明显,样品中共检测出45种挥发性物质,以酯类、醇类、酮类和芳香烃等化合物为主,其中可筛选出8种对胶黏剂的气味特征贡献最大的关键气味物质,包括丙酸丁酯、乙酸丁酯、3–甲基–4–庚酮、乙苯等。结论 胶黏剂的气味主要与使用的复杂化学成分有关,其生产加工过程应当引起高度关注。     

食品接触材料中有害物质迁移的研究进展

目的 综述目前食品接触材料中几种常用材料(纸、塑料、油墨)迁移与检测的研究进展,并指出几种材料未来的发展趋势,促使我国食品行业向着更绿色、更安全的方向发展。方法 概述纸质、塑料、油墨的发展趋势和材料中有害物质的来源;对比几种材料的迁移规律及迁移模型;总结几类常见有害物质的检测方法。结论 绿色环保的生物基材料是食品接触材料未来的发展方向,同时也需重视可持续性生物基食品接触材料的化学安全性。因其产生的化学品对人体健康的影响不甚明朗,因此需多方面研究生物基食品接触材料中化学物质的存在和迁移到食品中的情况,并采取相应措施减少包装材料的使用,降低材料中有毒有害物质对人体和环境的威胁。     

木质纤维素材料合成PHA预处理技术的研究进展

目的介绍木质纤维素材料的化学组成及结构,综述常见的木质纤维素材料预处理方法及其在合成包装材料聚羟基脂肪酸酯(PHA)方面的应用的研究进展。方法通过对国内外研究现状和研究成果分析总结,重点论述常见的木质纤维素材料预处理方法蒸汽爆破预处理、热水预处理、酸预处理、碱预处理、氨纤维爆破预处理、离子液体预处理、有机溶剂预处理等对木质纤维素材料糖化率的影响,及其在合成包装材料聚羟基脂肪酸酯(PHA)方面的应用。结果不同的木质纤维素材料和不同的预处理方法对最终产生的总糖含量及总糖内单糖种类和单糖占总糖质量分数产生很大的影响,其中将不同总糖(包含不同单糖种类和单糖占总糖的质量分数)作为碳源用于微生物发酵生产PHA,还会使形成PHA的单体及单体在PHA中的质量分数不同,形成具有不同性质的PHA,能广泛应用到包装领域中。结论关于国内外研究优化预处理和酶解工艺提高生成可发酵糖产量的研究有很多,热水预处理技术相较于其他预处理技术具有生产成本低、绿色环保等特点,因此,开发经济性好且适用于大规模工业化生产的热水预处理技术是今后值得关注的重点方向。     

The State of Research Regarding Ordered Mesoporous Materials in Batteries

Ordered mesoporous materials, porous materials with a pore size of 2–50 nm which are prepared via the sol–gel process using surfactant molecular aggregates as a template to assemble channels through the interfacial action of organic and inorganic substances, have recently triggered a heated debate. In addition to applications in the catalytic cracking of heavy oils and residues, the manufacturing of graft materials, the purification of water, the conversion of automobile exhaust, biochips, and the treatment of environmental pollutants via photocatalysts, ordered mesoporous materials have drawn substantial attention in the field of electrochemical energy storage due to advantages such as large specific surface area, uniform and continuously adjustable pore size, and orderly arrangement. Here, a general summary and appraisal of the study of ordered mesoporous materials for batteries in recent years is given, including the synthesis methods, meso/nanostructural features, and electrochemical capabilities of such materials.     

食品用金属包装中有害物质检测技术研究进展

食品接触材料中有害物质成分复杂、未知性强,通过对食品包装中有害物质进行迁移检测是食品评价安全的关键步骤。通常使用液-液萃取法、固相萃取法和辅助萃取法等对食品包装进行前处理,再通过高效液相色谱法、气相色谱-质谱法等对迁移到食品模拟物中的有害物质进行定量分析,从而评估食品包装的安全性。针对食品包装材料安全性研究还存在有害物质迁移机理不明确和检测方法不完善等问题,寻找高效前处理方式结合快速检测方法,且完善有害物质迁移机理建立迁移模型是以后的研究方向。     

Bricks made of coal fly-ash and slag, cured in the open air

Volume mass, compressive strength, water uptake and water absorption of pressed test samples made of a mixture of coal fly-ash, slag and sodium silicate solution (water-glass) were determined. It was found that such mixtures can solidify in the open air and form water-stable materials. The composition and structure of new formations for the binder and cured material itself were established using X-ray diffraction and a scanning electron microscope. The material has a high water uptake, which may be reduced using a number of different methods, the best of which is short-term impregnation with a hydrophobic material of the siloxane group. The water uptake and water absorption of compressed samples impregnated with such materials are similar to those of comparable building materials, such as lime-sand bricks, clay bricks or concrete blocks.     

Synthesis of Engineered Zeolitic Materials: From Classical Zeolites to Hierarchical Core–Shell Materials

The term “engineered zeolitic materials” refers to a class of materials with a rationally designed pore system and active‐sites distribution. They are primarily made of crystalline microporous zeolites as the main building blocks, which can be accompanied by other secondary components to form composite materials. These materials are of potential importance in many industrial fields like catalysis or selective adsorption. Herein, critical aspects related to the synthesis and modification of such materials are discussed. The first section provides a short introduction on classical zeolite structures and properties, and their conventional synthesis methods. Then, the motivating rationale behind the growing demand for structural alteration of these zeolitic materials is discussed, with an emphasis on the ongoing struggles regarding mass‐transfer issues. The state‐of‐the‐art techniques that are currently available for overcoming these hurdles are reviewed. Following this, the focus is set on core–shell composites as one of the promising pathways toward the creation of a new generation of highly versatile and efficient engineered zeolitic substances. The synthesis approaches developed thus far to make zeolitic core–shell materials and their analogues, yolk–shell, and hollow materials, are also examined and summarized. Finally, the last section concisely reviews the performance of novel core–shell, yolk–shell, and hollow zeolitic materials for some important industrial applications.     

食品接触橡胶材料中化学物质及迁移研究进展

目的综述食品接触橡胶材料中的一些化学物质及其迁移的研究现状,为相关研究提供参考。方法查阅并总结近些年来国内外食品接触橡胶材料的相关文献及已发布的相关卫生标准。结果橡胶在食品工业中应用广泛,由于橡胶材料复杂的配方成分及加工过程,使其在与食品接触的过程中会有一些潜在的化学物质迁移到食品中,从而对消费者健康带来危害。结论作为食品安全的重要组成部分,食品接触橡胶材料的安全问题不容忽视,其中的高关注度化学物质的检测标准和非目标化合物向食品中迁移的问题是今后研究的重点。     

RoHS Regulation: Challenges in the Measurement of Substances of Concern in Industrial Products by Different Analytical Techniques

The European Union’s as well as India’s reduction of hazardous materials (RoHS) directives state that producers of certain categories of electrical and electronic equipments will not be able to offer for sale any product that contains any of hazardous substances: Cd, Pb, Hg, Cr⁶⁺, polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE), bis(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) beyond the specified limits. Allowable concentration levels in any homogeneous material contained within a product are extremely low: 0.01% for Cd and 0.1% for other substances by weight. These substances when present in quantities in excess of the permissible limits are considered hazardous and damaging to the environment and human health. With the introduction of the RoHS Directive many manufacturing companies in the world are pursuing chemical testing as a means to identify and quantify these hazardous substances. This article presents various testing methods that are currently available to the manufacturing firms who need to generate data to prove that their products are compliant to the RoHS directive. The utility of portable X-ray fluorescence spectrometer (XRF) and also the potential of laser-induced breakdown spectrometer (LIBS) for rapid screening applications is described. For quantitative determination of Pb, Cd, Hg and Cr, the role of instrumental analytical techniques such as atomic absorption spectrometry, XRF, instrumental neutron activation analysis, inductively coupled plasma optical emission spectrometry, the inductively coupled plasma mass spectrometry (ICP-MS), LIBS and the potential of the new analytical technique, microwave plasma atomic emission spectrometry is discussed. Applicability of hyphenated techniques such as HPLC-ICP-MS for Cr⁶⁺, GC–MS for the determination of PBB, PBDE and phthalates, and the importance of certified reference materials, challenges and future trends are presented.     

Use of neutron radiography and tomography to visualize the autonomous crack sealing efficiency in cementitious materials

Penetration of moisture into building materials is at the origin of several damage mechanisms. In the case of cement-based materials crack formation is a common problem and highly accelerates the ingress of water and aggressive substances. Crack repair may be needed, however, repair works are expensive and in some cases cracks are even not accessible. Therefore, in this research we aim at autonomous crack sealing. Upon crack appearance, damage is sealed autonomously by the release of encapsulated agents. Visualization of the water uptake by means of neutron radiography for samples with manually and autonomously sealed cracks showed that in both cases ingress of water into the crack can be prevented depending on the type of agent. The efficiency of three different agents was examined and it was shown that the use of polyurethane or a water repellent agent were most promising. Neutron tomography scans demonstrated that poor results were obtained when encapsulated methyl methacrylate was used, since one component of the agent hardened inside the capsules before crack appearance. From the results we can conclude that autonomous sealing of cracks is feasible and that neutron radiography and tomography are suitable non-destructive test techniques to visualize the autonomous crack sealing efficiency.