纳米纤维素复合导电水凝胶的制备及其在传感器方面应用的研究进展

纳米纤维素作为一种可持续、可生物降解的纳米材料,通常会被加入到导电水凝胶中以改善其性能。本文讨论了纳米纤维素在不同导电水凝胶中的应用,详细介绍了纳米纤维素复合导电水凝胶的优点及其在柔性传感器中的应用。最后,展望了纳米纤维素复合导电水凝胶在柔性传感器应用中面临的挑战和未来发展方向。     

单宁/羧甲基纤维素水凝胶的制备及吸附性能

以单宁、羧甲基纤维素为单体,环氧氯丙烷为交联剂,制备单宁/羧甲基纤维素复合水凝胶。通过单体质量比、交联剂用量、交联时间3个因素,优化单宁/羧甲基纤维素复合水凝胶的制备工艺。以阳离子染料亚甲基蓝为有机吸附质,考察了染料初始质量浓度、pH、温度等因素对水凝胶吸附性能的影响。正交实验表明,制备单宁/羧甲基复合水凝胶的最佳条件为:单宁/羧甲基纤维素质量比1.2∶1.0,环氧氯丙烷用量0.8%,交联时间36 h。吸附实验表明,当亚甲基蓝初始质量浓度大于1 500 mg/L时,水凝胶中的空隙被填充,吸附位点趋于饱和,吸附量达到最大530.43 mg/g;pH在中性条件下有利于增加水凝胶与亚甲基蓝之间的静电吸附与络合作用,吸附率为80.2%;热力学数据表明,水凝胶对亚甲基蓝的吸附为自发放热物理吸附过程,在常温条件下更利于吸附的进行。     

羧甲基纤维素/聚苯胺复合凝胶球的制备及性能

以金属离子化合物FeCl_3为交联剂和氧化剂,采用物理交联法一步合成羧甲基纤维素/聚苯胺复合导电凝胶球,通过FT-IR、SEM和EDS对复合凝胶的分子结构和微观形貌进行表征;凝胶的失水率和电导率主要由FeCl_3、羧甲基纤维素和苯磺酸钠的浓度控制,当羧甲基纤维素浓度为4.5%、FeCl_3浓度为0.5mol/L和苯磺酸钠浓度为0.4mol/L时,凝胶的失水率为30.2%,具有最佳电导率5.2×10~(-3)S/cm。凝胶对甲基蓝的吸附比较稳定,在不同浓度的甲基蓝溶液中,吸附率保持在30%~50%左右,甲基蓝初始浓度在最大值14mg/L时,吸附量达到最大值17.58mg/g。     

超级电容器中纳米纤维素基水凝胶电极的研究进展

纳米纤维素表面含有大量羟基且长径比高,具有较好的润湿性和分散电活性材料的能力,是一种较好的电极材料基底,可作为超级电容器电极材料的优先选择。但是其缺点在于导电性不高,需要加入导电材料进行提升。本文归纳了纳米纤维素基水凝胶电极的分类,探讨了纳米纤维素基水凝胶电极的合成方法,对比分析了不同导电材料的纳米纤维素基水凝胶电极的电化学性能,并对其在未来应用领域的发展前景进行了展望。     

基于AlCl3/ZnCl2水体系高效构建纤维素/聚丙烯酰胺双网络水凝胶及其性能研究

近年来,具有优异机械性能、抗冻性能的离子导电水凝胶在人工智能、生物医药、柔性传感等领域受到了极大关注。本课题选取AlCl₃/ZnCl₂水体系作为纤维素原料的温和溶剂溶解纤维素,利用溶剂体系固有的金属离子引发丙烯酰胺单体的聚合反应,使聚丙烯酰胺网络与纤维素网络紧密搭接,制备得到纤维素基聚丙烯酰胺双网络水凝胶。通过控制丙烯酰胺与纤维素的交联比例实现对水凝胶机械性能和电化学性能等调控。研究结果表明,AlCl₃/ZnCl₂水体系中的金属离子赋予了水凝胶良好的抗冻性能（可在-45 ℃环境下正常工作）和导电性能（电导率可达2.04 S/m）,聚丙烯酰胺第二层聚合网络的巧妙搭建有效提高了水凝胶的机械属性,在60%的应变条件下,10次压缩循环测试中表现出良好的弹性性能。此外,制备的水凝胶与不同介质界面均存在较强的黏附作用。     

智能指示标签的制备及其在牛肉新鲜度监测中的应用

新疆牛肉品质优良,是新疆著名的畜产品资源之一.为了实现新疆牛肉新鲜度的实时监测,本文以羧甲基纤维素、聚乙烯醇为原料,利用物理冻融法制备水凝胶,并对水凝胶的物理特性进行表征;进一步筛选紫苏色素提取物为最佳显色色素制备智能指示标签,同时研究其对新疆牛肉冷藏过程中新鲜度的智能指示效果.结果表明:聚乙烯醇与羧甲基纤维素最佳比例...     

PVA/BC/LiCl复合水凝胶的制备及性能

为了探讨聚乙烯醇(PVA)/细菌纤维素(BC)/氯化锂(LiCl)复合水凝胶的制备及性能，以PVA作为水凝胶基质材料，BC作为增强材料，LiCl为导电物质，甘油-水混合物为溶剂，采用溶胶-凝胶法制备了PVA/BC/LiCl复合水凝胶材料，并对水凝胶材料的形貌结构、力学性能和电导率进行测试。结果表明：加入BC可以有效提高水凝胶的力学性能，加入LiCl可以明显提高水凝胶的电导率；PVA/BC/LiCl复合水凝胶具有良好的导电性能和力学性能。     

纤维素基水凝胶作为柔性超级电容器电解质的研究进展

传统超级电容器多使用液态电解质组装,然而其因过多外力而破损时,有毒且易挥发的液体电解质会发生泄露,进而引发安全隐患。为解决这一问题,需要开发柔性超级电容器,以抵抗外部力量的破坏。近年来,纤维素材料因绿色、经济和可再生的特点成为储能装置的理想材料,以纤维素基水凝胶组成的超级电容器表现出良好的物理、化学性能（如高柔韧性、优良的机械强度和导电能力）。纤维素基水凝胶在柔性超级电容器领域的应用已成为当前研究热点。本文综述了纤维素基水凝胶电解质的最新研究进展和成果,包括不同纤维素及其衍生物制备水凝胶电解质的性能与特点。最后,讨论了未来纤维素材料作为新能源材料的研究潜力和挑战。     

导电水凝胶的制备及用于应变传感器的研究进展

近几年,导电水凝胶因具有可拉伸性、导电性、刺激响应性和应变敏感性等多种性能,成为柔性可穿戴设备传感器的最优选择。总结了导电水凝胶的类型,综述了导电水凝胶基应变传感器的研究现状,展望了导电水凝胶的发展趋势。     

多功能纳米纤维素基水凝胶伤口愈合材料的研究进展

纳米纤维素具有良好的生物相容性和无毒性,基于纳米纤维素的新一代水凝胶伤口愈合材料研究逐渐成为热点,但用纳米纤维素制备水凝胶伤口愈合材料面临诸多挑战,如愈合材料的自愈合、促细胞增殖、抗菌和可注射性能的提高等。本文对纳米纤维素基水凝胶伤口愈合材料以上性能的提高研究进行了综述,重点讨论了纳米纤维素经改性、交联、复合等技术制备纳米纤维素基水凝胶的过程与方法,总结了合成机理并展望了纳米纤维素基水凝胶伤口愈合材料多功能化的发展趋势。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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