高性能纤维与纸基功能材料

<正>由高性能纤维制备的纸基功能材料可广泛应用于航天航空、轨道交通、先进绝缘等领域。本报告结合合成纤维的发展趋势,重点介绍了芳纶云母绝缘纸基材料、耐高温聚酰亚胺纸基材料、高性能纸基摩擦材料、芳纶纸基蜂窝材料的性质及目前存在的问题。同时,针对高性能纤维湿法造纸存在的共性问题,阐述了高性能纤维纸基材料的制备关键技术。     

国内造纸期刊题录(摘录)

正原料与备料15种竹材及其制浆造纸性能刘秀琼等纸和造纸2013,1:33聚酯纤维增强聚酰亚胺纤维纸基材料的研究王志杰等纸和造纸2013,1:41制浆生产木质生物质精炼预处理技术研究进展段超等中国造纸2013:1:59蒸煮渗透剂在杨木片碱法制浆中的应用王长建等中国造纸2013:1:74横管连蒸多段漂白工艺优化的实践与应用关建华等中华纸业2013,2:74高温预水解对杨木硫酸盐法制浆的影响段超等纸和造纸2013,1:20     

聚酰亚胺纤维及其纸基功能材料研究进展

特种纤维聚酰亚胺耐温等级高、绝缘性能优异、阻燃、耐辐射、高强高模,是轨道交通、航空航天、国防军工的重要基础工程材料,也是当下先进复合材料研究的热点之一。本文综述了国内外聚酰亚胺纤维和聚酰亚胺纸基功能材料的制备技术,探讨了聚酰亚胺纸基功能材料在制备方面面临的技术难题,并对聚酰亚胺纤维及其纸基功能材料的应用进行了展望。     

蒙脱土/聚酰亚胺纤维纸基材料绝缘及介电性能研究

本研究通过单因素分析法,探究了纸张定量及蒙脱土含量对聚酰亚胺纤维纸基材料的物理性能和介电性能的影响规律。结果表明,不同定量聚酰亚胺纤维纸基材料的外观无明显差别,当纸张定量为80 g/m²时,聚酰亚胺纤维纸基材料具有最优的物理性能,抗张指数和撕裂指数分别达15.0 N·m/g和19.7 mN·m²/g;当蒙脱土含量为6%时,蒙脱土/聚酰亚胺纤维纸基材料的体积电阻率最大,达2.59×10¹⁵ Ω·m;当蒙脱土含量达8%时,蒙脱土/聚酰亚胺纤维纸基材料具有最佳的绝缘性能,工频击穿强度达17.34 kV/mm,在50 Hz的频率下,其相对介电常数、介电损耗分别达4.99和0.23。     

聚酰亚胺纤维增强体制备及其对热塑性树脂基复合材料力学性能影响

利用湿法造纸成形技术抄取得到聚酰亚胺纤维纸,分别以等质量的聚酰亚胺纤维、聚酰亚胺纤维纸为增强体,采用手糊成型、热压法制备热塑性聚酰亚胺树脂集复合材料。聚酰亚胺纤维纸增强体改变了纤维的存在形式,解决了复合材料中纤维束多、纤维孔径分布不匀、有效长度低、材料力学性能不佳等问题,纸增强复合材料拉伸性能提高130%,弯曲性能提高108%,层间剪切性能提高34.5%。聚酰亚胺纤维纸增强体自身因素影响复合材料力学性能,从纤维长度、打浆状况、纸页定量角度分析了复合材料力学性能改善的原因。     

高得率浆的发展现状及高值化应用研究进展

我国制浆造纸行业一直面临着纤维资源短缺的问题。随着国家禁止进口固废政策的实施,造纸行业纤维原料的缺口进一步扩大。高得率制浆具有纤维资源利用率高、原料适应性广、工艺流程紧凑、设备投资少等优点,近年来受到广泛关注。本文首先对高得率制浆方法进行了简要介绍,探讨了高得率浆(HYP)的制浆工艺特点及浆料特性,分析了HYP的发展现状;并阐述了HYP在传统纸和纸板中的应用现状,详细论述了HYP在纸浆模塑包装材料、较高附加值纸制品、功能性复合材料以及高性能纸基材料中的高值化应用研究进展;最后,结合HYP的工艺完善和纸基功能材料的需求对HYP的发展进行了展望。     

用于浸渍聚酰亚胺纤维纸基复合材料树脂的研究

为了提升聚酰亚胺纤维纸基材料的强度、耐高温性、韧性及阻隔性能,本研究制备了具有高黏附力、易固化、柔韧性好、耐高温的浸渍树脂。首先用乙烯基硅树脂改性环氧树脂,以提高浸渍树脂的韧性及固化性,然后进一步添加聚酰亚胺树脂制备耐高温的三元合金树脂。结果表明,当乙烯基硅树脂用量30%时,改性后环氧树脂有较好的韧性及交联程度;此改性环氧树脂添加5%聚酰亚胺树脂时,三元合金树脂质量损失5%时的温度为339. 2℃,并且在高温下没有明显的玻璃化转变。分别用改性环氧树脂和三元合金树脂浸渍聚酰亚胺纤维纸基复合材料,结果表明,改性环氧树脂浸渍的纸基复合材料纤维结合程度较好,表面平整,接触角可以达到148. 71°,三元合金树脂浸渍的纸基复合材料耐高温效果好,200℃时纸基复合材料抗张指数仍能达到35. 1 N·m/g。     

纸基电磁屏蔽材料研究现状及发展趋势

介绍了纸基电磁屏蔽材料的屏蔽机理和屏蔽效能测试方法,综述了涂层型、导电纤维型和碳纳米管型纸基电磁屏蔽材料的研究进展,并对其发展趋势作出阐述,为后续纸基电磁屏蔽材料研究提供参考。     

超疏水纸基功能材料的应用研究进展

具有绿色环保、高性能、低成本等优点的纸基功能材料受到诸多关注。为突破纸基材料自身纤维亲水性等瓶颈,大量研究赋予了纸基材料优异的超疏水性能,从而制备了具有高附加值的纸基超疏水功能材料。本文主要阐述了超疏水纸基功能材料的最新应用研究进展,如油/水分离、食品包装、智能响应装置、传感器等新器件与装备领域,并对超疏水纸基功能材料的未来发展方向进行了展望。     

摩擦材料及纸基摩擦材料的研究进展

摩擦材料是一种应用在动力机械上,依靠摩擦作用来执行制动和传动功能的部件材料。它主要包括刹车片和离合器片。刹车片用于制动,离合器片用于传动。而纸基摩擦材料更是一种采用造纸技术和工艺制造,具有广阔市场价值的摩擦材料。本文重点介绍了摩擦材料和纸基摩擦材料的发展史和研究进展,通过将各种摩擦材料总结对比,从而提出纸基摩擦材料的主要研究方向。     

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.