纤维素纳米化处理技术研究现状

纳米纤维素因具有可再生、易改性以及优异的机械性能,在众多领域具有广阔的应用前景。植物来源的纳米纤维素主要包括纤维素纳米晶体和纤维素纳米纤维,本文主要介绍了以农副产品为原料的纤维素纳米化处理技术及其分类,包括制备纤维素纳米晶体的经典无机酸水解法以及有机酸水解法、低共熔溶剂法和离子液体法等新型制备方法。此外,还介绍了制备纤维素纳米纤维常用的预处理手段和制备方法,预处理方法包括以2,2,6,6-四甲基哌啶-1-氧自由基氧化为代表的氧化法预处理以及酶法预处理;制备方法包括高压均质、精细研磨、高强度超声和高压微射流等技术。最后,对现行纤维素纳米化处理技术中存在的问题进行综合分析,并探讨了其未来研究需求,以期为纳米纤维素的绿色高效生产提供理论参考。     

纳米纤维素的制备及其复合材料的应用研究进展

纳米纤维素包含纳米纤维素晶体、纳米纤维素纤维和细菌纳米纤维素3种类型。由于其具有高强度、大比表面积、高透明性等优良性能,成为目前纳米材料领域研究的热点。本文综述了近年来国内外纳米纤维素的主要制备方法,并对纳米纤维素在复合材料领域中的应用研究进行了总结。     

纳米微晶纤维素的表面基团及其改性

纳米微晶纤维素(Nanocrystalline Cellulose,NCC)是一种纤维素经酸水解后获得的棒状晶体,由于其原料丰富、可再生、生物兼容性好以及机械性能优良等特点,已成为纳米材料研究领域的热点。本文为探索其进一步改性应用,重点分析了NCC表面存在的基团种类,对其化学改性方法进行了概括,并对其进一步发展应用进行了展望。     

纳米纤维素及其在水性涂料中的应用研究进展

纳米纤维素具有高长径比、高结晶度、高杨氏模量、高强度等优点,加之其具有生物质材料的轻质、可降解及可再生等特性,使其成为一种改善水性涂料机械、光学、耐水等性能的优异选择。本文综述了纳米纤维素制备和改性方法,详细论述了纤维素纳米纤丝（CNF）和纤维素纳米晶体（CNC）对水性聚氨酯和水性丙烯酸涂料的性能改善机理及其应用研究进展。最后总结了纳米纤维素复合水性涂料研究现存的问题,并总结了未来的研究方向。     

源于食品加工副产物纳米纤维素晶体的制备及其在食品中的应用

近年来,作为一种环境友好材料——纳米纤维素,其制备及在材料、食品、化工、医药等领域的应用备受人们关注,其中纳米纤维素晶体具有高长径比、高比表面积、高结晶度、高机械强度和良好的热稳定性等优良特性。在介绍纳米纤维素晶体制备方法的基础上,对源于食品加工副产物纳米纤维素晶体的理化特性(形貌、结晶度、稳定性等)及主要应用方面(作为食品包装材料增强剂、Pickering乳液稳定剂、食品配料等)进行了全面综述,并对纳米纤维素晶体研究存在的问题及今后的发展方向进行了展望。     

纳米纤维素在食品行业中应用研究进展

概述了纳米纤维素的种类,包括微纤化纤维素、纳米纤维素晶体和细菌纳米纤维素,以及3种纳米纤维素的特性及其主要制备方法;重点介绍了纳米纤维素在食品领域的应用,主要包括其作为食品添加剂、功能性食品成分及食品包装材料等其他用途,并对其未来发展进行展望。     

氨基纳米纤维素的制备及其抗菌应用研究进展

良好的生物相容性和可降解性使纳米纤维素成为一种绿色材料,并广泛用于食品和化工等领域,将纳米纤维素进行氨基化改性得到的氨基纳米纤维素保留了纳米纤维素的优点,而且纤维表面的正电荷还增加了材料的抗菌性能,可应用于生物医药等领域。本文从纳米纤维素的制备入手,探讨了几类常见的纳米纤维素在制备方法和形貌尺寸等方面的特征和差异;重点介绍了纳米纤维素的氨基化改性方法,包括常用的氨基化试剂和改性工艺;最后综述了氨基纳米纤维素的抗菌机理和在抗菌材料中的应用。     

3D打印纳米纤维素凝胶材料

纤维素纳米晶体(CNCs)具有较好的制备性能,结晶度高、机械刚度大、强度高。然而,CNCs的高分散性限制了其可纺丝性。研究表明,对纳米纤维素氧化改性可以提高和优化材料的整体性能。选择氧化的纳米纤维素获得带有羧基的区域氧化CNCs(RO-CNC),利用多硫化钠(Na₂S_x)对CNCs末端区域进行氧化改性,制备了末端氧化纳米纤维素。对CNCs的形态进行表征,使用激光扫描制备的纤维素凝胶经诱导固化形成3D打印新材料。     

纳米纤维素的改性及其在复合材料中的应用进展

作为一种新型的纳米生物材料,纳米纤维素具有广阔的应用前景。本文给出了纳米纤维素的定义和分类,分析了其优良特性,详细介绍了对纳米纤维素进行化学改性的方法：小分子化学修饰和接枝共聚,综述了纳米纤维素在增强合成高分子材料和天然高分子材料及其衍生物中的应用进展,并对纳米纤维素在复合材料中的应用前景进行了展望。     

纳米纤维素的疏水性及分散性研究进展

纳米纤维素以其比表面积大、机械强度高、结晶度高、生物相容性好等优异性质在纳米复合材料中具有很好的应用前景,但易于团聚、亲水性极强的特点严重限制了其应用发展。本文综述了近年来提高纳米纤维素疏水性以及在水和大部分有机溶剂中分散性的方法、各方法的反应原理以及研究进展,如表面吸附改性、酯化改性、偶联剂改性和接枝共聚改性来提高其疏水性;表面吸附改性、阳离子改性、TEMPO氧化体系改性、乙酰化改性、偶联剂改性和接枝共聚改性来改善其分散性。同时也展望了纳米纤维素研究的发展方向以及应用前景。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.