高性能聚四氟乙烯覆膜滤料的制备与性能研究

用聚四氟乙烯微孔膜与聚四氟乙烯针刺毡通过高温热压覆合制备了一种纯聚四氟乙烯覆膜滤料。采用傅立叶红外光谱法和差示扫描量热法对纯聚四氟乙烯覆膜滤料进行组成分析,在图谱中未发现PTFE特征峰和PTFE非晶区的振动峰以外的其他图谱;通过扫描电镜对聚四氟乙烯覆膜滤料进行形貌观察,并对覆膜滤料的性能进行测试。结果表明:聚四氟乙烯微孔膜与聚四氟乙烯基布通过高温物理热黏合,与传统的覆膜滤料相比,纯PTFE覆膜滤料更能满足高温高湿高腐蚀性的烟气除尘工况要求。并展望了纯聚四氟乙烯覆膜滤料的应用前景。     

玻璃纤维/PTFE高温热压覆膜滤料的发展现状

叙述了高温烟气过滤材料的研究现状,分析了玻璃纤维/聚四氟乙烯(PTFE)覆膜滤料的表面过滤机理和与传统滤料相比其所具有的诸多优点。介绍了玻璃纤维/PTFE高温热压覆膜滤料的生产工艺,指出高温热压复合工艺是玻璃纤维/PTFE覆膜滤料品质的保证。     

无胶热压聚四氟乙烯覆膜高温滤料

采用自主研发的聚四氟乙烯（PTFE）发泡涂层剂对聚苯硫醚（PPS）滤料基材进行前处理,通过高温热压覆膜法制备了PTFE覆膜滤料。SEM观察发现该覆膜滤料的除尘机理为表面过滤,牢度测试及过滤性能研究得出PTFE薄膜与滤料基材结合牢固,覆膜滤料具有除尘效率高、过滤精度高、运行阻力低、易清灰、寿命长等特点,能有效控制PM2.5等超细粉尘的排放,可广泛应用于燃煤电厂、水泥行业、垃圾焚烧、化工厂及其它相关领域的高温烟气粉尘的治理。     

PPS/PTFE纤维复合水刺耐高温过滤材料的制备与性能研究

将PPS/PTFE纤网用水刺工艺覆盖在经过预针刺的"夹心层"结构的PPS纤网上,制得复合水刺滤料。试制了三种不同PPS/PTFE混合比的复合滤料,并测试了其基本性能和过滤性能。结果表明:PPS纤维与PTFE纤维的混合比对复合水刺滤料的性能有一定影响;该滤料具有高效率、低阻力、长寿命和耐高温等优良性能,可应用于高温除尘过滤领域;采用水刺工艺加工PPS/PTEF纤维复合耐高温滤料可以降低滤料的生产成本和提高其过滤性能。     

PTFE覆膜滤料在氧化铝焙烧使用中的过滤性能分析

氧化铝焙烧烟气净化多采用过滤除尘,而除尘的核心部位是滤料。由于氧化铝焙烧炉尾气具有高温、高湿、高腐蚀等特点,因此,选用PTFE覆膜滤料,通过AFC-133测试平台模拟工况,测试覆膜滤料的过滤效率和过滤阻力,证实PTFE覆膜滤料对氧化铝焙烧炉尾气中的粉尘具有高效捕集的作用,在1 m/min风速下,排放浓度为0.466 9 mg/m~3。     

高温环保过滤材料的现状及发展趋势

文章简述了高温环保过滤材料的发展概况与机理,介绍了传统与新型高温滤料用纤维的性能特点,梳理了针刺、水刺、静电纺等加工成型工艺及涂层、覆膜、除尘脱硝等后整理技术的研发状况,并剖析了当前高温滤料存在的问题,最后指出环保化、复合化、功能化、差别化、产业化将是我国高温过滤材料的重点研发方向。     

后处理工艺对聚苯硫醚滤料清灰性能的影响

为研究滤料清灰性能的不同影响因素,选取４种聚苯硫醚（PPS）纤维滤料,即未经后处理、烧毛、聚四氟乙烯（PTFE）乳液浸渍和PTFE 微孔膜覆膜处理的滤料为试样,采用滤料动态过滤性能测试仪测试了４种聚苯硫醚纤维滤料的清灰性能,通过扫描电镜观察了过滤前后滤料的表观形貌。测试结果表明：在试验周期内,这４种滤料中,覆膜滤料经粉尘过滤后剩余压差最低,清灰周期最长,清灰性能最为优异;未经处理滤料清灰性能次之;PTFE乳液浸渍滤料由于表面纤维间充满着PTFE 乳液固状物,其清灰性能较差;烧毛处理滤料表面留有面积较大的PPS 纤维烧焦物质,其清灰性能最差。     

PAN预氧化纤维高效复合滤料制备与性能

以PAN预氧化纤维为主要原料通过针刺工艺制备了复合滤料,并进行PTFE泡沫涂层处理,考察了涂层处理对滤料外观形貌、透气性、拉伸性能、孔径分布和过滤性能的影响。结果表明,涂层后滤料表面形成PTFE薄膜,滤料透气性和孔径减小,拉伸性能无明显变化;涂层后滤料对不同粒径过滤效率均有明显提高,对粒径≥2.5μm粒子的过滤效率高达98.11%;泡沫涂层整理滤料表面存在膜状附着物,粉尘不易进入滤料深层,滤料表面光滑易清灰,其清灰后残余阻力提高率和清灰周期降低率均减小。高温环境下,涂层滤料和稳定阶段过滤效率分别高达99.955 6%和99.915 8%。     

聚苯硫醚针刺材料的加工及其性能

聚苯硫醚(PPS)纤维制具有极佳的阻燃性、耐高温性和较好的热稳定性,耐腐蚀性仅次于聚四氟乙烯(PTFE)纤维。本文将PPS纤维通过梳理成网、针刺、后整理等工艺制成非织造材料,并对PPS高温滤料的过滤性能、耐酸性以及后整理工艺对产品性能的影响进行了分析。实验表明:PPS纤维具有一定的耐酸性,经过后整理的PPS针刺材料其过滤性能明显提高。     

针刺加固对耐高温过滤材料PTFE基布的影响研究

PTFE基布广泛适用在生产PTFE纤维耐高温过滤材料。本文根据耐高温过滤材料的规格,选用PTFE基布与PVA纤维网的复合方式,设计了针刺加固试验方案,观察、研究针刺后PTFE基布的性能变化,并对影响PTFE基布性能、滤料强力的针刺工艺因素进行了说明与讨论。     

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.     

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.     

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.     

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.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

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.