喷丝速率对连续水浴静电纺纳米纤维包芯纱结构与性能的影响

为实现工艺参数对纳米纤维包芯纱的结构调控，采用连续水浴静电纺丝的方法，以聚对苯二甲酸乙二醇酯(PET)纤维为芯纱，聚酰胺6(PA6)纳米纤维为包覆层，制备兼具纳米纤维特性和传统纱线力学性能的纳米纤维包芯纱。对PET/PA6纳米纤维包芯纱的形态、晶体结构和力学性能进行分析与表征。结果表明：纳米纤维包芯纱具有良好的皮芯结构；PA6包覆层的纳米纤维直径为66～80 nm,其孔隙率随喷丝速率的提高而下降，结晶度在19%～24.15%范围内，且随喷丝速率的提高而减小；PA6纳米纤维包覆层的断裂强度和断裂伸长率随喷丝速率的增大而降低，其断裂强度降为常规PA6纤维的1/5;纳米纤维包芯纱保持了芯纱的强力与断裂伸长率等力学性能。     

纳米纤维包芯纱的制备与表征

提出了一种制备连续的聚偏氟乙烯(PVDF)/粘胶纳米纤维包芯纱的方法——多针头静电纺。通过多针头静电纺原理集聚纳米纤维,用旋转的金属喇叭对纳米纤维进行加捻并包覆在芯纱表面。研究了纳米纤维包芯纱的形貌、疏水性能和力学性能。结果显示,PVDF纳米纤维在芯纱表面包覆比较均匀,且包覆在芯纱表面的纤维有较好的取向和均匀的捻回分布。PVDF纳米纤维包芯纱的力学性能较芯纱显著提高,断裂强度达到68.89 Mpa,伸长率26.51%,且具有良好的疏水性,表面接触角达到150°。     

镀银聚酰胺6/聚酰胺6纳米纤维包芯纱电容传感器的构筑

为获得线形螺旋结构且具有良好传感性能的大应变柔性应变-电容传感器，采用水浴静电纺丝法以镀银聚酰胺6为芯纱，制备了镀银聚酰胺6/聚酰胺6纳米纤维包芯纱，并将其缠绕在橡筋上制备应变-电容式柔性传感器。对纳米纤维包芯纱的结构与力学性能进行表征与测试，分析了应变-电容传感器的传感性能，并探索了其在人体运动监测中的应用。结果表明：聚酰胺6纳米纤维在镀银聚酰胺6表面形成结构完整的包覆层，直径分布主要在80～100 nm范围内，平均直径为95.53 nm;相较于芯纱，纳米纤维包芯纱的力学性能基本保持不变；制备的柔性传感器表现出良好的应变-电容传感性能，在6.67%的应变下敏感因子可达3.93,并具有良好的重复性，该传感器可用于人体运动的实时监测。     

纳米级聚砜酰胺包芯纱的阻燃效果研究

探讨新型结构的聚砜酰胺纤维的阻燃性能。采用静电纺丝装置制备了分别以涤纶、维纶、聚砜酰胺为芯纱、聚砜酰胺纳米级纤维为外包纤维的包芯纱,并测试了所制得各纱线的线密度和强力及所织成织物的阻燃性。结果表明:聚砜酰胺纳米级纤维的存在提高了织物的阻燃性能;聚砜酰胺纳米级纤维包覆后,纱线断裂强力略有提高。认为:包芯纱兼顾了二元纤维的优点,充分利用芯纱良好力学性能的同时发挥了聚砜酰胺纤维的耐高温阻燃性能。     

包芯纱

顾名思义,包芯纱就是纱芯用一根长丝或纱条,外面包覆一层短纤维(一般是天然纤维)。包芯纱的产生是受到钢筋混凝土的启发而产生的。天然纤维有许多优点,具有优良的服用性、卫生性和保暖性。由于纱线的强力或弹性还不够理想,于是纺织科技工作者就如何充分发挥各种纤维的优点,克服其缺点,做到扬长避短、物尽其用,研制成包芯纱的系列产品。目前,用于外包的纤维有棉纤维、毛纤维和山羊绒等。根据纱线的用途再选择纱芯,如     

双针头连续水浴静电纺的电场模拟及其纳米纤维包芯纱结构

为研究电场变化对皮芯结构纳米纤维包芯纱结构的影响，通过双针头连续水浴静电纺丝法制备了以涤纶长丝为芯纱，锦纶纳米纤维为包覆层，兼具纳米纤维特性和传统纱线力学性能的纳米纤维包芯纱。通过有限元分析软件ANSYS模拟其电场分布，探究了2个针头针尖间距对电场分布及纳米纤维包芯纱结构的影响。结果表明：静电纺丝最大电场强度出现在针尖处，随着针尖间距的增大，电场强度峰值呈现先增大后减小再增大的趋势；当针尖间距为20 mm时，纳米纤维间的黏结较多；随着针尖间距的增大，纳米纤维的形貌更加均匀光滑，其直径呈减小趋势，在针尖间距为80 mm时达到最小值(74.43±10.79) nm;当针尖间距从20 mm增加到60 mm时，纳米纤维包芯纱的孔隙率从20.27%提高到44.08%。     

涤纶短纤维包芯纱粗纱的生产

包芯纱是以长丝为纱芯、外包短纤维的复合纱,一般是在细纱机上完成两种纤维的包覆.某纺织企业采用日本尤尼吉可公司、德国SKF联合研制的FL -6改进型粗纱机,在粗纱机上完成以涤纶短纤维为纱芯、外包棉纤维的包芯纱纺制,填补了纺制包芯纱的一个技术空白,提供了一种新的开发高档面料的纺纱形式.     

热处理对摩擦纺包芯纱性能的影响

讨论了DREF-3型摩擦纺包芯纱包覆层组分的比例(包覆率)以及在干、湿自然状态下热处理对纱热收缩性、包覆层抗滑脱性及拉伸性能的影响。芯纱采用聚酯长丝，包覆层为棉纤维。实验表明热处理能够明显提高纱线的热收缩性与包覆层抗滑脱性能，而且在湿状态下包芯纱的抗滑脱性能较干状态更好。纱断裂伸长随着处理温度的增加而增加。包覆率提高，纱热收缩性降低，抗滑脱性提高，断裂强力增加。     

棉涤包芯纱与棉涤混纺纱及其织物的比较

包芯纱的结构包含两个组份,一个形成中心轴或纱芯,另一个形成包覆层。通常,纱芯为长丝复丝纱,而外包层为切段纤维。加工工艺可以方便地采用传统的环锭细纱机稍作更改。包芯纱能改善织物的强力、耐久性、美观以及其他功能特性。本研究的目的是发展具有较佳强力及耐     

两种包芯纱的工艺优选及质量对比

探讨传统环锭纺包芯纱与赛络纺包芯纱的细纱工艺参数优化及芯纱包覆效果、成纱质量对比。细纱工序选择钳口隔距、后区牵伸倍数和捻系数进行三因子三水平正交试验,对条干CV、强力、毛羽等成纱质量指标进行测试,得出条干CV值的优化工艺为:钳口隔距3.5mm,后区牵伸1.39倍,捻系数402。对传统环锭纺包芯纱与赛络纺包芯纱的芯纱包覆效果与成纱质量指标进行对比分析,结果表明:传统环锭纺包芯纱的包覆效果、成纱质量均优于赛络纺包芯纱。认为:无论是纺制传统环锭纺包芯纱还是赛络纺包芯纱,都应控制好芯纱的喂入位置,从而保证良好的芯纱包覆效果。     

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