可重复使用防护口罩的制备与性能评估

探讨可重复使用防护口罩的制备工艺,并对其性能进行评估。基于聚酰亚胺纳米纤维膜制备可重复使用防护口罩,对其视野、死腔、呼吸阻力、过滤效率、总泄漏率等性能指标以及50次洗涤后的过滤效率与呼吸阻力进行了测试和分析。结果表明:所制备的防护口罩性能指标超过KN 95级防护口罩的技术要求,且历经50次洗涤后过滤效率与呼吸阻力依然超过KN 90级防护口罩的技术要求。认为:聚酰亚胺纳米纤维膜可作为重复使用防护口罩的过滤材料。     

熔喷非织造过滤材料直径对医用口罩过滤性能的影响

为研究熔喷非织造过滤材料直径对医用口罩过滤性能的影响,指导高效低阻的医用防护口罩的制备,对医用防护口罩、医用外科口罩、医用颗粒物防护口罩和医用普通及护理口罩四大类共7种非织造医用口罩的纤维直径和过滤性能进行了测试,研究了直径对过滤效率的影响。研究表明:纤维直径越小,过滤效率越高;纤网的直径粗细不均匀时,直径变异系数越大,过滤效率越高。     

梯度结构耐高温纤维过滤材料的结构与性能

为探究梯度结构纤维过滤材料的制备工艺对过滤材料结构、性能的影响,制备了聚苯硫醚纤维-聚四氟乙烯超细纤维(PPS-PTFE)滤料,并分析了制备工艺(超细纤维层面密度和水针能量)对结构和过滤性能的影响,建立了对应的二次方模型。结果表明:超细纤维层的面密度对孔径大小和过滤效率均有显著的影响,随着超细纤维层面密度从(49±3.8)g/m~2增大到(181±12.5)g/m~2,试样的模态孔径从20.22μm降低到12.52μm,而对2.05μm颗粒物的过滤效率从63.41%提高到91.87%;水针能量在3 738~8 755 J/g范围内,过滤效率和过滤阻力均随着水针能量的增大而增大;建立的二次方模型的置信度高,表明模型适用于梯度结构的耐高温纤维过滤材料的工艺设计。     

PET纤维截面形状对液体过滤材料过滤性能的影响

对3种不同截面形状（圆形、三叶形和丰字形）的PET纤维进行了形貌分析及水中分散性能研究,通过将其与阔叶木闪急浆混抄制备过滤材料,探究了PET纤维截面形状对过滤材料液体过滤性能的影响。结果表明,PET纤维含量相同时,相比于含圆形PET纤维的过滤材料,含三叶形和丰字形PET纤维的过滤材料在过滤效率、流阻、纳污容量等过滤性能方面都有不同程度的改善。三叶形纤维更有利于提高过滤材料的过滤效率,而丰字形纤维更有利于提高过滤滤材的纳污容量、降低滤材的过滤阻力。当PET纤维含量为40%时,相比于含圆形PET纤维的滤材,含三叶形和丰字形PET纤维过滤材料的纳污容量分别增加了32.1%、26.5%;对粒径14 μm颗粒的过滤效率分别提高了13.1%、6.1%。液体流量在4 L/min时,流阻分别降低了26.6 %、28.5%。     

非织造医用防护口罩过滤材料结构与过滤效率关系的研究

为了制备高效低阻的医用防护口罩,对医用防护口罩、医用外科口罩、医用颗粒物防护口罩和一次性医用普通及护理口罩4大类共8种非织造医用防护口罩的厚度、面密度、孔隙率、平均孔径、纤维直径和过滤性能进行了测试,研究了各结构参数对过滤效率的影响。研究表明:随着过滤材料厚度、面密度的增大,过滤效率随之增大;随着平均孔径和纤维直径的减小,过滤效率呈增大趋势;过滤效率随孔隙率的变化规律性不强;经SPSS多元回归分析,5个结构参数对过滤效率的影响权重依次为:平均孔径纤维直径平均厚度孔隙率面密度。     

抗菌防沾污生物防护材料的制备及其性能

为保护医护人员生命健康安全,研制了一种兼具抗菌和阻隔功能的可重复使用生物防护材料。首先以纳米银(AgNPs)为抗菌剂,热塑性聚氨酯(TPU)为基体,通过静电纺丝技术制备载银TPU纳米纤维膜;然后以聚二甲基硅氧烷(PDMS)为疏水整理剂,涤纶织物为基材,通过等离子体刻蚀—浸轧PDMS—焙烘工艺制备防沾污织物;最后将制备的载银TPU纳米纤维膜与防沾污织物进行点胶复合制备生物防护材料。测试了生物防护材料的抗湿性能、透湿性能、防水性能及过滤性能等。结果表明：经过50次标准洗涤后,防沾污织物的水接触角达到143.1°;纳米银负载量为300 mg/kg的生物防护材料对大肠杆菌和金黄色葡萄球菌的抑菌率均达到99.99%,且沾湿等级达到5级,水蒸气透过量为2 654.8 g/(m²·24 h),断裂强力为450 N左右,静水压为53.6 kPa,过滤效率达到99%以上。     

原料对KD-100液体过滤材料结构与性能的影响

本文以不同纤度的涤纶纤维为原料,经过水刺加固、聚丙烯酸酯黏合剂上胶制备KD-100液体过滤材料。在其他工艺参数不变的情况下,分析研究了不同纤度的涤纶纤维配比及聚丙烯黏合剂含量对液体过滤材料结构与性能的影响。结果表明,低纤度的纤维使材料的平均孔径、过滤阻力降低;高纤度纤维有利于提高材料过滤稳定性及改善力学性能。随着聚丙烯酸酯黏合剂含量的增加,滤料的平均孔径和孔隙率减小、过滤阻力和过滤效率增大、纵横向断裂强度升高、断裂伸长率降低。     

聚四氟乙烯复合过滤材料的覆膜工艺及其性能

为了探索聚四氟乙烯(PTFE)复合过滤材料的制备工艺及性能,以不同种类PTFE膜为主要原料,无纺布作为基材,采用不同的覆膜方式制备PTFE复合过滤材料。研究PTFE膜的种类、覆膜方式对PTFE/无纺布复合过滤材料性能的影响,以及熔喷布与PTFE/无纺布复合过滤材料两者性能之间的不同。结果表明：以PTFE-A膜为原料,采用胶覆方式所制备的PTFE/无纺布复合过滤材料的通气阻力要比热覆的低,且过滤效率能达到99%,该材料的过滤效率和通气阻力能符合口罩标准要求。     

PET纤维截面形状对过滤纸结构和性能的影响

采用5种截面形状(圆形、三角形、三叶形、十字形、丰字形)的PET纤维与植物纤维配抄过滤纸,探究PET纤维截面形状对过滤纸结构和性能的影响。结果表明,与圆形纤维相比,三角形、三叶形、十字形以及丰字形纤维对过滤纸的过滤效率没有显著影响,但容尘量都有不同程度的提高。PET纤维添加量为40%时,与圆形纤维相比,含三角形、三叶形、十字形和丰字形纤维过滤纸的容尘量分别增加了8.2 g/m~2、11.7 g/m2、9.9 g/m~2、13.8 g/m~2。其中,三叶形纤维和丰字形纤维对过滤纸的厚度和容尘量的影响较大,丰字形纤维比三角形、三叶形和十字形纤维对过滤纸的孔径和透气度具有更显著的影响。     

PVA负载中药纳米纤维的制备及空气过滤应用

口罩是重要的个人防护用品,现有口罩多采用无纺布材料,存在滤效低、功能单一等缺陷。纳米纤维具有比表面积大、纤维直径细、孔隙率高等优点。利用静电纺丝技术制备聚乙烯醇(PVA)中药缓释纳米纤维,并对其性能进行测试表征。结果显示:当中药质量分数为10%(PVA质量分数为8%)时,纤维形貌规整,分布均匀,平均直径为227 nm。此时PVA中药缓释纳米纤维膜的断裂强力为4.32 MPa、断裂伸长率为32.53%、面密度为1.286 g/m2。将此纳米纤维膜与15 g/m2的无纺布复合后的过滤效率和过滤阻力分别为94.68%和44.04 Pa。     

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