Pullulan‐based films and coatings for food packaging: Present applications,emerging opportunities,and future challenges

Societal and industrial demands for lower environmental impact, cost effectiveness, and high‐performance goods and services are increasingly impacting the choice of technologies which are developed and deployed in consumer products. Like many other sectors, food packaging is moving to new technologies; the use of biopolymers is one of the most promising strategies toward an optimized use of traditional packaging materials (e.g., oil‐based plastics) without impairing the goal of extending shelf life. Among other food packaging materials, pullulan is attracting much attention due to its unique features. The goal of this review is to provide an overview of current and emerging applications of pullulan within the food packaging sector. In particular, the functional properties of interest for the food packaging industry will be discussed in light of the physicochemical attributes of this exopolysaccharide. Future challenges that may dictate the successful penetration of pullulan in the food packaging market are also outlined. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40539.     

介-微孔ZSM-5分子筛的原位合成

在ZSM-5合成过程中引入高分子量三嵌段共聚物P123,原位合成介-微孔ZSM-5分子筛,采用XRD、IR、BET和TEM对材料进行表征。结果表明,合成材料的主体结构为ZSM-5分子筛,比表面积为372 m²·g^-1,孔体积为0.226 mL·g^-1,其中,介孔比表面积为44 m²·g^-1,介孔孔体积为0.068 mL·g^-1,为介-微孔分子筛的合成开发了一条全新的技术路线。     

介孔沸石材料合成研究进展

综述了6种合成介孔沸石材料的方法,包括脱铝脱硅法、热处理法、硬模板法、原位合成法、孔壁晶化法和沸石前驱体纳米自组装法。举例阐述了每种方法的合成过程及优缺点,并提出了介孔沸石材料合成方法的研究方向,指明了其发展前景。     

Selective synthesis of 2-methylquinoline over zeolites

The selective vapour-phase synthesis of 2-methylquinoline by alkylation of quinoline with methanol was carried out over HY, HZSM-5(30), CrHY, CeHY, LaHY, LaKHY and CeHZSM-5(30) zeolites in a fixed-bed reactor at atmospheric pressure. The yields of 2-methylquinoline over modified zeolites, especially those of doubly promoted LaKHY, were found to be higher than those of unmodified zeolites. The maximum yield of 2-methylquinoline obtained was 60.6 wt% at 91.5 wt% selectivity over LaKHY zeolite. The active sites responsible for this methylation were found to be more on Lewis acidic sites available over zeolite systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

纳米分子筛制备及其自组装体系的研究进展

纳米分子筛具有短而规整的孔道和较开放的晶穴,不仅在催化、离子交换和复合材料方面显示优异性能,而且在分子组装、光电磁功能纳米材料制备上也是一种优良的载体材料或宿主材料。对纳米分子筛的研究还利于从深层次了解分子筛的核化和生长机理。介绍了近年来纳米分子筛合成方法的研究进展,并对合成方法进行了分类综述,同时对纳米分子筛的特点及晶化机理进行归纳,进一步对纳米分子筛在催化反应中的应用及纳米自组装体系的新成果做了概述,指出了纳米分子筛研究的几个主要方向。     

Catalytic activity of zeolites for synthesis reaction of methylenedianiline from aniline and formaldehyde

The catalytic activities of Y-, β-, and ZSM-5-zeolites for methylenedianiline (MDA) synthesis from the condensation reaction of aniline and formaldehyde have been investigated. Among β-zeolites with various Al concentrations (Si/Al ratios from 10 to 120 mol mol⁻¹), β-zeolite with Si/Al ratio of 13.6 mol mol⁻¹ shows the best catalytic performance in MDA synthesis. Y-zeolite exhibited lower catalytic activity than β-zeolites under the identical reaction conditions, however, exhibited the higher selectivity to 4,4′-MDA. Furthermore, it revealed that aniline/formaldehyde and catalyst/formaldehyde ratio, and reaction temperature also influenced on the MDA yield and isomers distribution.     

Gas phase synthesis of MTBE on fluoride-modified zeolites

The gas phase synthesis of MTBE was studied using three series of zeolites modified by ion-exchange with ammonium fluoride, the parent materials being HY, H-mordenite, and HZSM-5. Modification of zeolites by fluoride-exchange was found to enhance the MTBE synthesis activity for all three types of zeolites without impairing their excellent selectivity to MTBE. The mechanism of activity enhancement by fluoride-modification appears to be related to the formation of extra-lattice Al rather than the presence of fluoride-ions.     

空心结构沸石分子筛合成研究进展

空心结构沸石分子筛具有由沸石分子筛微孔构成的壳层及由微孔孔道环绕形成的介孔或大孔空腔,呈现出特殊的、优异的性能,成为化学和新材料科学等领域研究热点,其合成和制备受到越来越多的关注.本文对空心结构沸石分子筛的合成方法进展进行总结阐述,指出扩展空心结构沸石在新兴领域的应用,开发出普适性、重现性好,成本低廉易于工业化合成方法...     

Recent trends in the synthesis of high-silica zeolites

Novel zeolites continue to be synthesized using organic structure directing agents in combination with unconventional choices of inorganic conditions. The latter include synthesis in concentrated fluoride media, synthesis in concentrated hydroxide media, synthesis in the presence of germanium, and synthesis with high concentrations of boron. Post-synthetic treatments of germanosilicates with the ADOR method have resulted in fully intact zeolites that cannot be obtained through direct synthesis. Unusual compositions of known frameworks have been obtained through topotactic condensation of layered precursors. Coupled with the appropriate choice of inorganic conditions, the use of new SDA molecules has also produced materials with known frameworks but with amazingly small crystal dimensions that are less than 10 nm. The preparations of once “exotic” materials are now being performed with commercially available or easily prepared organic structure directing agents. In some instances methods have been found to prepare high-silica zeolites from seeded preparations in the absence of an organocation. Methods to target zeolite catalysts for a particular reaction have been realized by identifying structure directing agent molecules that are a mimic of the transition state of the reaction.     

Hydrothermal synthesis of zeolites from coal fly ash

The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were synthesised from the fly ash: analcime, faujasite (zeolite X) and gismondine (zeolite P). It was shown that the experimental conditions (temperature, reaction time and alkali concentration) have a significant influence on the type of zeolite and its content in the reaction products. The series of experiments resulted in building approximate crystallisation field of zeolites and other phases as the first stage of the formation of ceramic membrane and other materials.     

Two-dimensional nanomaterials for photocatalytic water disinfection: recent progress and future challenges

Photocatalysis has received ever-growing attention as a promising alternative to traditional water treatment technologies for waterborne biohazard inactivation. Due to unique optical, electronic, physicochemical properties and feasibility of functional architecture assembly, two-dimensional (2D) nanomaterials have become important in developing novel photocatalysts. This review summarizes the recent progress in configuring nanostructures with 2D materials as building blocks for photocatalytic water disinfection. In this review, five categories of 2D nanomaterials, that is, graphene, graphitic carbon nitride, 2D metal oxides and metallates, metal oxyhalides and transition metal dichalcogenides, for photocatalytic pathogen inactivation are introduced. First, the synthesis process, nanostructure engineering and disinfection performance of 2D-based photocatalysts are reviewed in categories. In the following section, the bacteria destruction mechanism based on the generation and roles of reactive species (RSs) is presented. Moreover, the effects of the chemical characteristics of the water matrix on photocatalytic bactericidal performance are discussed. Finally, the challenges regarding the development and application of 2D-based photocatalysts for highly efficient water sterilization are highlighted. © 2018 Society of Chemical Industry     

世界SR技术现状与发展趋势

论述了SR的技术现状并预测了其发展趋势。世界SR技术的主要进展为 :生产装置实现高功能化和高产能化 ;工艺条件进一步优化 ,过程自动化水平提高 ,生产成本降低 ,三废排放减少 ;新产品不断出现 ,品种牌号向系列化、高性能化和专用化发展 ;气相聚合技术实现工业化 ;茂金属催化剂弹性体工业化产品问世 ;分子设计工程技术得到广泛应用 ;活性聚合技术取得突破性进展 ,而且弹性体改性技术成为开发的热点     

苯酐的市场现状和发展趋势

介绍了国内外苯酐的市场需求和价格情况以及发展趋势。     

甲基叔丁基醚的市场现状和发展

介绍了甲基叔丁基醚国内外的生产、消费现状，认为甲基叔丁基醚在国内有很大的潜在市场。     

无机盐工业的现状和发展趋势

介绍了无机盐工业的现状和发展趋势及其市场情况。     

Vinyl chloride technology: Present and future

The main lines of development in the technology of vinyl chloride in the midterm are considered. It is shown that the balanced process based on ethylene remains the main method of vinyl chloride production despite an increase in the fraction of vinyl chloride production from acetylene in China. Technological solutions that would favor the intensification of current technologies, especially at the stages of dichloroethane pyrolysis and the oxidative chlorination of ethylene, will play important role in the development of these processes. A possible method for the increase in the productivity of dichloroethane pyrolysis is the use of initiators that make it possible to increase the conversion of dichloroethane, decrease the temperature of the process, decrease power consumption, and increase the period of furnace operation without recovery. For the processes of oxidative chlorination of ethylene with the use of fluidized-bed catalysts, a low-active catalyst is recommended together with an increase in the process temperature to 250–260°C. This makes it possible to increase the real productivity of the catalyst and the overall stage by a factor of 1.8–2 because of intensified heat removal in the reactor without a decrease in the selectivity of the process.     

中国化妆品行业的现状与未来

介绍了中国化妆品行业发展概况,指出了行业存在的问题,对中国化妆品行业未来发展的思想、目标及战略措施进行了详细阐述,展望了未来发展方向。