氧化石墨烯/聚偏二氟乙烯复合纤维过滤膜的制备及其过滤性能

为得到高过滤效率、低过滤阻力的空气过滤材料,将氧化石墨烯掺入以聚偏二氟乙烯(PVDF)为基体,N,N-二甲基甲酰胺与丙酮为混合溶剂的纺丝液中,利用静电纺丝技术制备高性能氧化石墨烯/PVDF复合纤维过滤膜。研究不同聚偏二氟乙烯质量分数、氧化石墨烯质量分数、静电纺丝电压、接收距离等参数对复合纳米纤维过滤膜外观形态、过滤效率、过滤阻力的影响。结果表明:聚偏二氟乙烯质量分数为16%,氧化石墨烯质量分数为1.0%,静电纺丝电压为29.0 kV,接收距离为16 cm时,制备的复合纤维过滤膜形貌较好,纤维连续且均匀,过滤效率为99.99%,过滤阻力为11.53 Pa/μm,具有良好的过滤性能。     

石墨烯/PAN静电纺/PP纤维针刺复合空气过滤材料的制备

对适用于全新风系统的高效低阻并具有抑菌性能的复合空气过滤材料进行研发。先将聚丙烯腈(PAN)静电纺纳米纤维膜沉积到优选的丙纶(PP纤维)针刺过滤材料上,测试其过滤性能,采用极差分析和灰色聚类分析法选出最优静电纺丝工艺参数;再配制石墨烯质量分数分别为0.5%、1.0%和1.5%的石墨烯/PAN静电纺丝液,基于最优静电纺丝工艺参数,制备石墨烯/PAN静电纺/PP纤维针刺复合空气过滤材料,测试并分析其过滤性能和抑菌性能。结果表明:制备PAN静电纺纳米纤维膜的最优静电纺丝工艺参数为PAN质量分数11.0%、纺丝电压15 kV、注射速度0.84 mL/h、接收距离14 cm;在最优静电纺丝工艺参数条件下,石墨烯质量分数为0.5%时,石墨烯/PAN静电纺/PP纤维针刺复合空气过滤材料的过滤性能最好。石墨烯/PAN静电纺/PP纤维针刺复合空气过滤材料高效低阻,并具有优良的抑菌性能,适用于全新风系统过滤室内空气中的微细颗粒物。     

高过滤性能石墨烯复合纳米纤维膜的制备及性能

将石墨烯(GR)纳米颗粒掺杂到聚丙烯腈(PAN)纺丝溶液中,利用静电纺丝技术制备石墨烯/聚丙烯腈(GR/PAN)复合纳米纤维膜。研究PAN质量分数、GR用量、纺丝电压及接收距离对GR/PAN复合纳米纤维膜形貌和过滤性能的影响,发现最优纺丝工艺参数为PAN质量分数14.0%、GR用量1.5%、纺丝电压26 kV、接收距离14 cm、注射速度1 mL/h。此最优纺丝工艺参数制备的GR/PAN复合纳米纤维膜的过滤效率为98.86%,过滤阻力为110.30 Pa。     

GO掺杂PVDF纳米纤维的制备及应用

静电纺纳米纤维具有比表面积大、纤维直径细、孔隙率高等优点,广泛应用于空气过滤、防水透湿等领域。采用静电纺丝技术,通过在聚偏氟乙烯(PVDF)中掺杂不同质量分数的氧化石墨烯(GO)来制备PVDF/GO复合纳米纤维,并利用扫描电镜对复合纳米纤维膜的形貌结构进行表征测试。结果显示:当纺丝电压为15 kV时, PVDF纳米纤维形貌较为规整,纤维粗细分布均匀,平均直径为537.61 nm;在PVDF机制中掺杂0.2%GO时,出现了较多的超细纳米纤维,粗细纤维分布较为明显;当纳米纤维膜具有一定厚度时,显示了较好的过滤效率,其过滤效率和过滤阻力分别为99.84%和44.38 Pa。由此可见,所制备的GO掺杂PVDF纳米纤维在空气过滤领域有较大的应用前景。     

PU/PVDF防水透气共混膜的制备及性能研究

采用静电纺丝法制备聚氨酯/聚偏氟乙烯(PU/PVDF)共混纳米纤维膜,研究PU、PVDF质量分数、溶剂体积配比、溶质质量比对纳米纤维形貌、直径及膜性能的影响,探索共混纤维膜较优制备工艺。结果表明:共混纳米纤维膜较优制备工艺为静电纺丝电压14 kV、接收距离10 cm、纺丝液质量分数12%、溶剂体积配比N,N-二甲基甲酰胺/丙酮为4/6、溶质质量比PU/PVDF为7/3,此条件下可获得具有较优防水透气性能和力学性能的共混膜。     

复合静电纺超细聚丙烯腈纳米纤维的制备

为获得比常规静电纺丝纤维直径更细的聚丙烯腈（PAN）纳米纤维,采用复合静电纺丝方法制备了聚丙烯腈/醋酸丁酸纤维素（PAN/CAB）复合纳米纤维,再溶解掉复合纳米纤维中的CAB组分,得到超细PAN纳米纤维并对其进行氨基化改性后用于吸附直接红23（DR23）染料。研究了PAN和CAB的混合比例、纺丝溶液质量分数和纺丝液挤出速度3个因素对所得ＰＡＮ 纳米纤维直径的影响,并比较了常规静电纺和复合静电纺制备出的PAN纳米纤维改性后的染料吸附量。实验结果表明：该方法制得的PAN纳米纤维的平均直径在50~80 nm范围内,其中当PAN和CAB的质量比为15:85、纺丝溶液质量分数为15%、纺丝液挤出速度为1.5 mL/h、纺丝电压为10 kV、接收距离为20 cm时,得到的PAN纳米纤维的平均直径为50 nm;改性后纳米纤维对DR 23的平衡吸附量达833mg/g。     

静电纺PVA/SA复合纳米纤维膜制备工艺的优化

通过调节溶液质量分数、质量比、纺丝电压、供液速度、接收距离和辊筒转速等工艺参数,探讨不同条件对静电纺聚乙烯醇(PVA)/海藻酸钠(SA)复合纳米纤维膜的影响,制备纤维形貌优良的复合纳米纤维膜。使用场发射扫描电镜(FE-SEM)观察复合纳米纤维膜的形貌,并分析纤维直径及其分布。结果表明:最优工艺参数为聚乙烯醇质量分数10%、海藻酸钠质量分数2%、质量比8∶2、纺丝电压19 kV、供液速度1.6 mL/h、接收距离19 cm、辊筒转速300 r/min。此时,可得到形貌良好、分布均匀,平均直径为120.8 nm的复合纳米纤维。     

静电纺钛酸钡/聚偏氟乙烯纳米复合柔性压电纤维膜

为进一步提高聚偏氟乙烯（PVDF）压电性能,采用具有铁电性能的钛酸钡(BaTiO3)纳米颗粒为无机填料,通过静电纺丝技术制备BaTiO3/PVDF纳米复合纤维膜。借助扫描电子显微镜、全反射红外光谱、差示扫描量热法、X射线衍射以及脉冲电压测试等仪器对纤维膜的结构和性能进行了表征及分析,探索了不同添加量的BaTiO3对复合纤维膜结晶结构及压电性能的影响。结果表明：静电纺丝过程中静电力的拉伸和纳米BaTiO3的成核作用促进了PVDF具有压电性的β晶型的形成;当BaTiO3质量分数为10%,复合纤维膜的β晶型含量达到90.8%,纤维膜的输出电压值由20 V增加至50 V;制得的BaTiO3/PVDF复合纤维薄膜具有良好的压电性。     

静电纺丝法制备氧化石墨烯/聚偏氟乙烯复合纳米纤维

采用静电纺丝法,添加不同质量分数的氧化石墨烯(GO)制备GO/聚偏氟乙烯(GO/PVDF)复合纳米纤维。利用扫描电子显微镜对复合纳米纤维的微观结构进行观察,并计算纤维的平均直径和标准偏差。结果表明,添加GO时,所纺纤维的表面粗糙度明显增加,纤维表面不光滑,凹凸不平;随着GO质量分数的增加,纤维的平均直径增大,直径标准差变化不显著;当GO的质量分数过高时,纤维无法成型。     

SiO2原位掺杂聚偏氟乙烯纳米纤维膜的制备及其性能

为提高聚偏氟乙烯(PVDF)的压电性能,以PVDF和正硅酸乙酯(TEOS)为原料,N,N-二甲基甲酰胺(DMF)和丙酮为混合溶剂,利用原位复合溶胶-凝胶法和高压静电纺丝技术制备纳米SiO₂原位掺杂PVDF复合纳米纤维膜,并分析纳米纤维膜的表面微观形貌、化学结构、力学性能以及压电性能等。结果表明:复合纳米纤维膜的面密度与厚度随TEOS质量的增加而增加;静电纺丝使PVDF中部分α相转变为β相,纯PVDF纳米纤维膜的β相含量是PVDF粉末的1.54倍,为(31.42±0.62)%;且原位掺杂SiO₂后β相含量进一步提高,拉伸强力与输出电压均呈先增大后降低的趋势,当TEOS质量为1.643 g时PVDF纳米纤维膜β相含量最高为(42.59±0.62)%,原位掺杂PVDF纳米纤维膜拉伸强力最大为(8.03±0.19) N,输出电压最高为(2.33±0.13) V。     

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.     

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