不同复配乳化剂合成乳液对汽车工业滤纸强度性能的影响

以苯乙烯和丙烯酸酯为主要单体,设计多种复配乳化剂方案,通过单体预乳化、半连续乳液聚合法合成苯丙乳液,用作汽车发动机空气滤清器滤纸浸渍树脂.研究了多种复配乳化剂合成苯丙乳液浸渍对汽车工业滤纸抗张强度、耐破度及挺度的影响,筛选出对滤纸强度性能作用效果良好的复配乳化剂.结果表明,合成乳液浸渍对提高汽车工业滤纸抗张强度、挺度及耐破度作用显著,OP-10/FR-1、OR-2/DSB、FOR-3/RE-610复配乳化剂乳液浸渍的汽车工业滤纸抗张强度高于3.15kN/m、挺度大于3.45 mN·m、耐破度在250 kPa以上.     

机油滤纸的实验研究

以植物纤维与合成纤维为原料,采用复合抄片及树脂浸渍工艺研制出了透气度性能良好的机油滤纸。经检测该滤纸平均最大孔径83.7μm,耐破度464kPa,挺度17.1mN.m。     

改性水溶性酚醛树脂的合成及在三滤纸中的应用

制备了改性水溶性酚醛树脂,用于过滤纸的浸渍增强,通过对酚醛树脂浸渍和固化工艺的研究以及过滤纸性能的比较表明,水溶性酚醛树脂用于浸渍增强滤纸是可行的,其裂断长达到4880m,耐破度309 kPa,挺度3.3 mN·m,综合力学性能均已达到进口产品水平.     

聚磷酸铵制备阻燃型空气过滤纸

分别采用Ⅰ-APP（结晶Ⅰ型聚磷酸铵）和Ⅱ-APP（结晶Ⅱ型聚磷酸铵）为阻燃剂制备内燃机用阻燃型空气过滤纸,并对其阻燃性、吸湿性、透气性和力学强度等性能进行比较。实验结果表明：与Ⅰ-APP相比较,Ⅱ-APP制备的阻燃型空气过滤纸的综合性能更优异,当苯丙乳液的留着率为20%,Ⅱ-APP的留着率为15%时,滤纸的阻燃性即可满足GB/T14656-93的阻燃要求,且耐破度与只浸渍20%苯丙乳液的滤纸相比,增加了23.8%,挺度和吸湿率基本保持不变,透气度仅下降16.5%。     

环氧树脂改性苯丙乳液用作浸渍树脂可提高汽车滤纸强度及耐水性能

研究人员以苯乙烯和丙烯酸酯为主要单体,引入E-20、E-44两种环氧树脂,采用预乳化半连续乳液聚合法制备改性苯丙乳液,并将其用作汽车滤纸浸渍树脂。结果表明,环氧树脂改性苯丙乳液浸渍的滤纸,挺度、耐破度、耐水性能都得到提高,透气度、孔径与未改性乳液相比持平或略微下降。     

环氧树脂改性苯丙乳液及其对汽车滤纸性能的影响

以苯乙烯和丙烯酸酯为主要单体,引入E-20、E-44两种环氧树脂,采用预乳化半连续乳液聚合法制备改性苯丙乳液,对环氧树脂改性后的苯丙乳液性能及在汽车滤纸中的应用效果进行检测分析。结果表明,用环氧树脂改性苯丙乳液,并将其用作汽车滤纸浸渍树脂,滤纸的挺度、耐破度、耐水性能都得到提高,透气度、孔径与未改性乳液相比持平或略微下降。环氧树脂的用量在1%~3%范围内,使用E-20改性的苯丙乳液的汽车滤纸强度和耐水性能明显优于E-44改性的。     

内燃机用空气过滤纸的阻燃性研究

为了提高内燃机用空气过滤纸的阻燃性能,实验探讨了聚磷酸铵阻燃剂、溴-锑协同阻燃剂以及二者的复配阻燃剂分别在不同留着率条件下对空气过滤纸的阻燃效果、力学性能以及透气性的影响。结果显示：复配阻燃剂在留着率为20%,且聚磷酸铵阻燃剂与溴-锑协同阻燃剂留着率之比为1∶1时,滤纸的阻燃性能满足GB/T14656-93的要求且无烟,此时挺度基本不变,耐破度下降约12%,透气率下降约13%。     

聚乙二醇改性三聚氰胺甲醛树脂对汽车空气滤纸性能的影响

采用聚乙二醇对三聚氰胺甲醛树脂进行改性,改性后的树脂用作交联剂添加到苯丙乳液中,并对汽车工业滤纸原纸进行浸渍加工处理。通过研究聚乙二醇(P)、三聚氰胺(M)、甲醛(F)的不同配比、树脂添加量及固化pH值,探讨了其作为乳液交联剂对汽车工业空气滤纸的抗张强度、耐破度、耐水性、透气度的影响。实验结果表明,当P与M的摩尔比为0.32,F与M-MP的摩尔比为2.8,改性树脂添加量为苯丙乳液固含量的4%,固化pH值为6～7时,汽车工业空气滤纸的综合性能最佳(苯丙乳液的上胶量为25%)。当pH值为6时,滤纸的抗张强度为4.51 kN/m,耐破度为340 kPa,耐水性为39.4min,透气度为334 L/(m2.s)。     

酚醛树脂合成条件及其与苯丙乳液复配体系对浸渍滤纸性能的影响

介绍一种苯丙乳液与酚醛树脂复配体系,针对酚醛树脂合成过程中用碱量和保温时间不同,研究并比较滤纸用酚醛-苯丙乳液复配体系和纯乳液分别浸渍增强后的多项力学性能。结果发现:酚醛树脂用碱量为11%,保温时间为3.5h,复配体系浸渍固化滤纸后力学性能相对乳液浸渍的滤纸有较大幅度的提高,其中耐破度可提高20%,抗张强度、伸长率和挺度均有不同程度的提高,达到了既降低成本又提高滤纸力学性能的目的,对工业应用有指导意义。     

水溶性酚醛树脂对机油滤纸性能影响的研究

研制了一种新型改性水溶性酚醛树脂,用于增强机油滤纸,探讨了浸渍、固化等加工工艺对浸渍增强滤纸力学性能的影响,并分析了浸渍滤纸的耐机油性能。研究结果表明,浸渍滤纸力学性能得到明显改善,上胶量为20%时其耐破度可达350 kPa、弯曲(7.5°)挺度3.55 mN·m、抗张强度6.22 kN/m;浸泡机油后耐破度保持率为44%;该树脂游离醛含量小于1%,较以往水溶性酚醛树脂增强滤纸的综合性能有更进一步提高,已经达到进口产品水平。     

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