水溶性PVA纤维对包装纸增强作用的研究

在高强度包装纸抄造过程中,使用水溶性PVA纤维做增强剂,研究了水溶性PVA纤维的添加量、加入方式、磨浆条件对增强效果的影响.结果表明,添加水溶性PVA纤维后,纸张抗张强度显著提高,裂断长提高幅度为18.8%～45.8%,撕裂指数、耐破指数也有不同程度的改善.研究确定了水溶性PVA纤维的最佳使用条件为:PVA60用量为6%,两段磨浆,程序升温干燥,此时抄片各项强度指标有不同程度的提高,裂断长提高45.8%,撕裂指数提高32.9%,耐破指数提高17.3%.研究表明水溶性PVA纤维是一种有效的纸张增强剂,制备的高强度纸包装材料生物降解性能好,是真正的绿色包装材料.     

水溶性聚乙烯醇纤维作纸张增强剂的研究

研究了水溶性PVA纤维预处理温度、添加量、后续纸张干燥温度以及磨浆方式对纸张物理性能的影响。结果表明:水溶性聚乙烯醇纤维在常温下直接添加且在纸张中的添加量为4%、后续纸张干燥温度100℃时,可提高纸张干抗张指数约14%、撕裂指数约19%、耐破指数约16%、耐折度约121%,降低湿变形约30%。另外,发现对于纸张的增强性能,添加PVA纤维后采用两段磨浆方式要优于一段磨浆方式。     

高填料纸增强性能的研究

主要研究了粉煤灰提取物硅酸钙填料在纸张中的高留着(≥50%)带来的强度下降问题,并寻找提高高填料纸强度性能的可行性方案和工艺。研究结果表明,高填料纸的增强效果可以通过采用添加增强剂、纤维与填料共同磨浆、应用纤维性增强剂、纸张表面施胶等方法来完成。经过对比研究发现,采用纤维与填料共同磨浆并表面施胶,PAE用量0.7%、阳离子淀粉用量1.5%、拉力增强剂ZY-1用量0.2%,CMC用量0.3%时,纸张抗张指数可以达到21.3N·m/g。其中,磨浆转数为300r,打浆度48°SR,且在阳离子淀粉:CMC∶PVA=2∶1∶2的条件下施胶两次。当纤维性增强剂用量为23%,并且表面施胶后,纸张抗张指数达到27.3 N·m/g,比未添加纤维性增强剂时的抗张指数提高了28%。     

改性酚醛树脂在OCC浆中的应用及其增强机理

通过苯酚、甲醛与二乙烯三胺反应,得到阴离子性的酚醛树脂,并将改性的酚醛树脂作为造纸增强剂应用在抄纸过程。结果表明,单独使用改性酚醛树脂时增强效果不显著;改性酚醛树脂和阳离子淀粉共同使用能有效提高纸张的抗张指数和环压指数。通过对改性酚醛树脂和阳离子淀粉用量的优化得到最佳使用条件,即改性酚醛树脂和阳离子淀粉用量分别为0．3％和0．7％,纸张的抗张指数和环压指数分别增加了35．28％和26.50％。由改性酚醛树脂增强机理的试验结果表明,改性酚醛树脂能使浆料在加入阳离子淀粉的情况下分散更均匀;改性酚醛树脂和阳离子淀粉能有效提高纤维之间的结合强度。     

对聚乙烯醇纤维改性改善成纸性能的研究

该文通过对聚乙烯醇(PVA)纤维改性改善成纸的性能作了研究。对针叶木浆以及瓦楞原纸浆中加入PVA纤维混合抄纸,对纸张物理性能的检测结果表明:加入PVA纤维后,纸样的撕裂度、裂断长及环压指数均有明显的提高。水溶性PVA纤维可作为纸张增强剂及花色纤维应用于纸浆纤维中,成纸有较好的强度,挺度及均匀性,可用于防伪、高档包装等用途。     

纺织用纸线原纸的研究

分析了进口纸线原纸的纤维形态、组成及配比;测定了原纸的各项物理性能指标;研究了在针叶木浆中配加棉浆、细菌纤维以及水溶性PVA纤维对纸张强度性能的影响.结果表明当纤维配比为木浆纤维棉浆纤维细菌纤维水溶性纤维=81∶10∶7∶2,且分散剂PEO用量0.07%,湿强剂PAE用量1.8%,CMC用量0.3%时,纸线原纸的主要物理性能为干抗张指数71.10 N·m/g,湿抗张指数30.03N·m/g,撕裂指数8.01 mN·m2/g,耐折度460次、伸长率2.46%.     

PVA-硫酸铝改性白泥纤维及其对纸张性能的影响

采用聚乙烯醇(PVA)与硫酸铝(Al2(SO4)3)合成一种疏水性改性剂(PVA-Al)对白泥纤维进行改性,研究了改性剂的最佳制备条件以及改性白泥纤维作为填料对纸张性能的影响。结果表明,改性剂最佳制备条件为:温度80℃、时间90 min、m(PVA)∶m(Al2(SO4)3=1∶0.5;在此条件下合成的改性剂改性得到的白泥纤维抄造的纸张强度性能最佳。与加填未改性白泥纤维的纸张相比,当白泥纤维加填量为40%时,加填改性白泥纤维的纸张留着率提高了19.0%;当白泥纤维加填量为30%时,加填改性白泥纤维的纸张环压指数和抗张指数均增加了25%。     

硼砂/PVA对酸化老化纸张的脱酸增强作用研究

选取硼砂作为脱酸剂,聚乙烯醇(PVA)作为增强剂,将二者以一定比例配制的硼砂/PVA复合液作为酸化老化纸脱酸增强剂,研究了硼砂与PVA配比、硼砂/PVA在纸张中的用量对纸张性能的影响;并通过加速老化实验,研究了处理后纸张的耐老化性能。研究结果表明,当W硼砂:WP VA为2:1,用量为2 g/m~2时,对处理的纸张脱酸增强效果相对最好,处理后纸张pH由6.53提高到8.12,同时纸张的抗张指数和撕裂指数比原纸(未处理的纸)分别增加了15.9%和72.93%,且白度与原纸相差不大;对各纸样进行加速老化实验,硼砂/PVA处理后纸张的pH仍保持较高,为7.78,而原纸为5.75;抗张指数为57.80 N·m/g,高于原纸的45.28 N·m/g;撕裂指数为2.85 mN·m~2/g,高于原纸1.78 mN·m~2/g;硼砂/PVA处理后的纸张耐久性得也到改善,表现为纸张纤维素降解受到抑制,TG分析半衰期温度T50%明显提高,由338.49℃上升到346.86℃。     

VF—SM—DMDAAC共聚物无皂乳液的纸张增强性能研究

研究了乳胶粒径、表面阳离子量不同的NVF—SM-DMDAAC共聚物（PNSD）乳液在碱性条件下对按木纸张的增强作用。试验结果表明：PNSD的纸张增强效果随乳胶粒径的减小而增强,与表面阳离子量和添加量成正比例,其中粒径最小的PNSD—C1在添加量为0．25％时,纸张干、湿抗张指数和环压指数分别增大18％、54%和26％;表面阳离子量大的PNSD—P4在添加量为0．25％时,可使纸张干、湿抗张指数和环压指数分别增大23％、49％和33％。     

PAE-苯乙烯接枝共聚物乳液的稳定性及增强效果探讨

以PAE、苯乙烯为主要原料,在过硫酸铵-亚硫酸氢钠氧化还原引发体系下合成PAE-苯乙烯接枝共聚物乳液,并讨论了合成条件对乳液稳定性的影响及产物在造纸中的应用。作为瓦楞原纸增强剂时,添加1．0％（对绝干浆）的乳液,纸张的环压指数、挺度、抗张指数、耐破指数和耐折度可分别比空白样提高19．75％、27．02％、30．72％、32．06％和80％。最后通过扫描电镜分析了加入乳液前后纸页中纤维的交织情况,结果显示加入该聚合物乳液的成形纸页中的纤维结合更加紧密,说明其增强效果明显。     

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