疏水纳米纤维织物的仿生制备及性能表征

将静电纺丝技术和编织技术结合,分别制备了纯聚偏氟乙烯(PVDF)和聚偏氟乙烯/聚乙二醇(PVDF/PEG)两种纳米纤维织物。通过水解去除PEG,仿生构造了类似荷叶表面结构的多级超微粗糙纳米纤维表面。讨论了不同PEG含量对纤维表面粗糙度的影响,研究了其力学性能和浸润性能。结果显示:水洗之后的PVDF/PEG复合纳米纤维表面呈现凹凸不平的形貌;当PEG含量为10%时,纤维表面结构类似于荷叶表面的"小山包",纤维直径约在300~400 nm;PVDF/PEG纳米纤维织物的应力较纯PVDF纳米纤维织物有所增加,而应变降低,分别为92.12 MPa和17.53%;两种织物均具有较好的疏水性,其中PEG含量为10%的PVDF/PEG纳米纤维织物显示出超疏水性,接触角为155.71°。     

PP与PVDF疝修补片的力学性能研究

聚丙烯(PP)补片是疝修补术中最为常用的补片材料之一,具有良好的力学性能与生物性能;聚偏二氟乙烯(PVDF)一种是较新的补片材料,具有优于PP的生物性能,但是关于两种补片的力学性能并未有过详细的对比分析。针对这个问题,本文做了一些对比研究,包括拉伸性能、抗拉性能、顶破性能和弹性。测试结果表明,PVDF补片具有较大的断裂伸长率、抗拉强力、顶破强力和弹性回复率;PVDF补片的力学性能均能满足人体对疝修补片的最低需求,并且与PP补片相比,具有更好的形状稳定性和弹性。     

聚偏二氟乙烯（PVDF）经编疝修补片的力学性能研究

无张力疝修补是当前治疗疝气的主要手术方式,研究和应用最多的手术用修补材料是聚丙烯（PP）补片。近期有研究表明,聚偏二氟乙烯（PVDF）是一种理想的替代PP的补片材料。采用PVDF单丝,选择三针开口经缎结构和热定型工艺,制备了PVDF疝修补片,测试了该补片的硬挺性、拉脱性、拉伸性、弹性回复性及顶破性等力学性能,试验结果显示该补片具有良好的力学性能。     

聚偏氟乙烯/铌酸锂复合驻极纳米纤维膜的制备及其空气过滤性能

通过水热法制备出铌酸锂(LiNbO_3,简称LN)纳米粒子,并将其作为驻极粒子加入到聚偏氟乙烯(PVDF)纺丝溶液中,通过静电纺丝工艺制成聚偏氟乙烯/铌酸锂(PVDF/LN)复合纳米纤维。通过过滤性能测试发现,与纯PVDF纳米纤维相比,LN纳米粒子的存在极大地提高了复合纳米纤维膜的过滤效率,质量分数为1%的PVDF/LN纤维膜过滤效率最佳可达99.98%,阻力压降为84.28 Pa。     

防护口罩用改性长效聚(偏氟乙烯-三氟乙烯)压电纤维膜的制备及其性能

聚丙烯(PP)熔喷布表面自由电荷易在湿气等作用下流失,导致过滤层及口罩快速失效。针对以上问题,采用静电纺丝技术在PP熔喷布基体上制备压电聚(偏氟乙烯-三氟乙烯)(P(VDF-TrFE))纤维层,得到PP熔喷布/P(VDF-TrFE)改性过滤层。探究了纺丝工艺对压电纤维形貌和结构的影响,进一步分析了改性过滤层经过水洗、蒸汽等耐久性处理后的静电压、烟雾过滤效率和透气性的变化。结果表明：PP熔喷布/P(VDF-TrFE)改性过滤层对PM_2.5的过滤效率较PP熔喷布提高了25%,在进风量为85 L/min时的过滤效率提升了27.5%;经过2次水洗、紫外线照射、蒸煮消毒等方式处理后的改性过滤层,其表面电荷具有多次弯折后可再生的特点,过滤效率维持在90%,有效提高了口罩的防护效率和使用寿命,压电材料在外力作用下可产生束缚电荷,改善了过滤层负载电荷的稳定性,从而提升了口罩防护的长效性和安全性。     

聚合物表面接触角与低温等离子体辐照生成自由基的相关性

利用低温等离子体对聚丙烯(PP)和聚四氟乙烯( PTFE)薄膜进行表面亲水改性.通过改变等离子体处理工艺参数、材料的化学结构以及工作气体的种类,探索其对材料表面水接触角和过氧基团浓度的影响规律,确定较优化的等离子体处理条件.结果表明:较优化处理条件为处理时间4 min、功率400 W、气体流量100 cm3/min;改...     

聚多巴胺诱导纳米TiO_2自组装改性PP纤维及其抗紫外性能

采用溶胶凝胶法制备纳米二氧化钛(TiO_2),利用聚多巴胺(PDA)的高黏附性对聚丙烯纤维表面进行修饰,再将纳米TiO_2与PP纤维表面的PDA结合,制备抗老化聚丙烯纤维。结果表明:制备的纳米TiO_2被成功改性到PP纤维表面,并在PP纤维表面形成了均匀、致密,且牢固结合的纳米TiO_2薄膜层。经长时间紫外光照射后,改性后的PP/PDA/TiO_2纤维的强力比原PP纤维有明显提高,且强力下降速率明显降低;改性后PP/PDA/TiO_2纤维的抗紫外光老化能力也有显著提升。     

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。     

PVDF纳米纤维材料的制备及抑菌性能

聚偏氟乙烯（PVDF）具有优良的机械性能、热稳定性和稳定的化学性能，被广泛用于膜分离领域，但其表面的高疏水性使其在使用时容易被细菌和蛋白质等污染，从而降低使用寿命。采用纤维共混改性[二氧化钛（TiO2）与PVDF共混静电纺丝]和Au/Ag-TiO2涂层整理两种改性方法制得PVDF纳米纤维膜。经过改性后，PVDF纳米纤维膜的力学性能和热稳定性能相较于改性前无明显变化，但抗菌性能显著提高，尤其是经过涂层处理的纳米纤维膜，抑菌率高达95%以上。     

高导电性铜/聚吡咯涂层羊毛织物的制备与表征

为研究等离子体处理时间对铜/聚吡咯/羊毛复合织物的导电性能,拓展羊毛织物在柔性传感器领域的应用,利用等离子体气相沉积技术对羊毛进行去鳞片化处理,依次对羊毛织物预处理300、600、900、1 200 s,然后在羊毛织物表面原位聚合构建聚吡咯膜层,并用磁控溅射沉积铜薄膜增强纤维表面的导电网络;借助扫描电子显微镜、傅里叶红外光谱仪和热重分析仪等手段表征了铜/聚吡咯/羊毛导电织物的结构和导电性,同时研究了铜/聚吡咯/羊毛导电复合织物的力学性能。结果表明:等离子体处理时间为1 200 s时制备的铜/聚吡咯涂层毛织物具有良好的导电性和力学性能,平均方阻为67.32 Ω/□;经水洗2 h后,铜/聚吡咯涂层毛织物的方阻优于未经等离子体处理的聚吡咯/羊毛织物,耐水洗性能较稳定。     

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.     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.