改性麻浆制备PM2.5口罩滤纸的研究

以(剑)麻浆为原料,采用NaOH-尿素-硫脲溶液体系对其进行改性,再利用超声波对其进行协同打浆处理,使纤维发生润胀、氢键破坏、结构松弛,产生分丝和微纤化,并用其抄造精细滤纸,达到PMZ.5口罩滤材的过滤性能。采用正交实验的方法,探讨试剂质量分数、改性温度、改性时间、超声波处理时间等因素对纤维改性效果的影响;通过改性前后麻浆纤维形态变化及所抄造滤纸性能等的对比分析,并参照3M公司9502型PM2.5口罩的各项性能检测数据综合评价改性效果。结果表明,在试剂质量分数24%、改性温度-6℃、改性时间20min、超声波处理时间60min的最佳改性条件下,改性麻浆纤维形态发生明显变化,抄造的滤纸透气度为313.12 L/(m~2·s),平均孔径32.43μm,最大孔径36.95μn,松厚度5.26 cm~3/g,滤纸过滤性能达到预期目标,满足PM2.5口罩滤材的性能要求。     

溶剂法改性纸浆纤维可打浆性探索及其对滤纸性能的影响

用氢氧化钠/尿素/硫脲体系作为改性试剂,对纸浆纤维进行改性,使纤维充分润胀,再结合机械打浆处理的方式使纤维分丝帚化。在保证滤纸具有较好的透气、过滤性能前提下,赋予纸张强度性能。通过比较打浆效果和纤维形态的差异,探讨溶剂法改性纸浆纤维的可打浆性;通过检测滤纸的透气度、孔径、松厚度、强度等指标,分析打浆程度对改性纸浆纤维滤纸性能的影响,并得出适合抄造滤纸的打浆工艺。     

纸浆纤维的改性及其用于口罩滤材的制备性能研究

以漂白硫酸盐针叶木浆(NBKP)、漂白硫酸盐阔叶木浆(LBKP)为原料,利用氢氧化钠∕尿素∕硫脲溶剂体系在低温环境下进行改性,通过协同打浆处理,得到整体形态不变的、适当分丝帚化的纸浆纤维,并用于制备口罩滤材。通过测试滤材松厚度、孔径、透气度等结构参数和性能,与市售PM2.5防护口罩滤材对比,探究合适的纸浆纤维改性工艺及配抄方案。结果表明,改性后的NBKP打浆度18°SR、LBKP打浆度20°SR,二者质量比2∶8时,制备滤材各项性能指标与市售口罩最接近,其松厚度为4.36 cm³/g,透气度为287.19 L/(m²·s),平均孔径为36.69μm,最大孔径为39.86μm,对6000目滑石粉过滤效率可达99%。     

麦草化学浆抄造轻型印刷纸的研究

以高孔隙率合成硅酸钙为填料,以生产轻型印刷纸常用的纸浆配比为基础,逐步提高纸浆中低白度麦草化学浆的比例,考察以100%低白度麦草化学浆加填合成硅酸钙抄造轻型印刷纸的可行性。结果表明,以高孔隙率合成硅酸钙为填料、低白度麦草化学浆配抄轻型纸时,随着麦草化学浆逐渐替代化学木浆和化机浆,填料留着率呈上升趋势,手抄片的不透明度、抗张强度和抗水性均逐渐提高,松厚度稍有下降,白度下降;以100%麦草化学浆加填合成硅酸钙采用动态纸页成形器抄造轻型印刷纸并压光至所要求的平滑度时,与常规浆料配比加填PCC在相同条件下抄造的轻型纸相比,松厚度从1.74 cm~3/g提高到1.88 cm~3/g,抗张指数从34.2 N·m/g提高到44.5 N·m/g,吸水值从47.0 g/m~2降低到35.9 g/m~2,不透明度基本保持不变,高达92.6%,白度从80.3%降低到71.7%,符合轻型印刷纸的白度要求。综合来看,麦草化学浆加填合成硅酸钙抄造轻型印刷纸,成纸质量较好。     

超声波预处理改善速生杨化学机械浆性能的研究

用超声波预处理速生杨碱性过氧化氢机械浆(APMP),通过分析检测处理前后纸浆纤维的表面形态、打浆度及成纸的物理强度性能,探讨超声波处理的时间和强度对速生杨高得率浆抄造性能的影响。实验结果表明,与未用超声波处理的纸浆相比,在超声波功率150W下处理90min,纸浆打浆度提高了5°SR,不透明度提高了3.1%,抗张指数提高了2.8N·m·g~(-1),撕裂指数提高了0.15m·N·m~2·g~(-1),白度几乎无影响。超声波预处理速生杨高得率浆,使得纸浆纤维表面和内部受到超声空化作用,纤维变得松散,细纤维化程度加深。     

一种阻燃性空气滤纸的研制

本论文主要对空气滤纸的阻燃处理和苯丙乳液浸渍处理进行了探讨。选用的纤维原料为丝光浆、针叶木浆和聚丙烯纤维,其绝干量比为40∶40∶20,针叶木浆的打浆度选为30°SR,经质量分数为4%的阻燃剂溶液浸渍后,再经过固含量为4%的苯丙乳液固化,所得空气滤纸的最大孔径为37.20μm,平均孔径为10.95μm,最小孔径为3.27μm,透气度为130L/(m2.s),滤纸的续焰时间和灼焰时间都为0s,炭化长度为4m m。可见,滤纸具有一定的阻燃性能,且其他物理强度也都满足行业标准QB/T 4031-2010。     

松厚度对高效滤纸结构和性能影响的数值模拟研究

本研究利用数值模拟软件建立了不同松厚度的滤纸模型,探究了松厚度对高效滤纸结构和性能的影响,得到特定过滤等级滤纸的优化方案。结果表明,滤纸的平均孔径和品质因子随滤纸松厚度的增大而增大,过滤阻力和过滤效率随滤纸松厚度的增大而减小,在不同松厚度范围内变化的程度不同。当松厚度范围在1.25～5.00 cm3/g时,其对过滤阻力和品质因子有显著影响;当松厚度范围在10.00～30.00 cm3/g时,其对过滤阻力和品质因子影响较小。当松厚度从1.25 cm3/g增大到30.00 cm3/g时,5种滤纸模型的平均孔径增大约500%,过滤阻力减小了75%～80%,过滤效率下降了0.23%～1.06%,品质因子增加了113%～121%。随着配抄纤维直径的减小,松厚度对滤纸过滤阻力影响越明显,对过滤效率影响越小,对品质因子的影响先降低后增大。因此,可以通过增大滤纸松厚度来制备特定过滤等级下品质因子更高的滤纸,实现高效滤纸的性能优化。     

纤维表面润湿性能及其与纤维结合性能的响应关系研究

对南方松热磨机械浆纤维进行PFI磨浆处理,通过"液桥法"分析纤维接触角,进而计算表面能用于表征纤维表面润湿性能,最终建立纤维表面润湿性能与纤维结合性能之间的响应关系。结果表明,随着机械处理程度的加深,纤维表面木素含量从87. 13%降低到77. 51%,纤维表面润湿性能得到改善(表面能从46. 63 m J/m~2上升到54. 45 m J/m~2,表面电荷从48. 382 mmol/kg上升到60. 382 mmol/kg),结合强度指数从4. 63 N·m/g提升到10. 9 N·m/g。实验发现,纤维表面润湿性能与结合强度指数以及纸张的松厚度之间存在二次函数关系,且相关系数均大于0. 9。从表面润湿性能与松厚度之间的关系方程可知,纸张松厚度随纤维表面润湿性能降低而降低的较小,在整个机械处理过程中从4. 95 cm~3/g下降到3. 57 cm~3/g,这表明可通过改善纤维表面润湿性能来达到在不显著影响纸张松厚度的前提下提高纤维结合性能的目的。     

木质素改性水溶性酚醛树脂在轻型纸中的应用

该文研究了木质素改性水溶性酚醛树脂在提高轻型纸松厚度方面的应用。实验结果表明,通过木质素-酚醛树脂与木粉配合进行浆内添加,对于提高纸张的松厚度有明显的效果,对纸张强度有一定影响,对白度没有明显影响。实验中,用木粉替代部分浆料,分别用不同用量的木质素-酚醛树脂和阳离子淀粉与木粉配合进行浆内添加抄造定量为60 g/m~2的纸张,同时用100%化机浆抄造纸张。在木质素-酚醛树脂添加量为1.5%、木粉添加量为20%时效果较好,所抄纸张松厚度提高36.9%,抗张指数下降12.9%,白度下降1.3%。     

低档纸浆抄造空气滤纸的研究

空气滤纸要求具有良好的抗张强度、耐破度、挺度。目前,空气滤纸原纸主要由天然植物纤维抄造而成,在需要特殊性能(如高温、超高精度)时,需要添加无机或合成纤维以提高滤纸性能。在不影响使用性能要求的前提下,也会掺入短纤维阔叶木浆以获得较好的成型纸页,同时降低生产成本。但滤纸的生产依然以高档纸浆为主,少有低品质浆种。本研究选取四种廉价易得的低档纸浆:闪干浆、阔叶木浆、热磨机械浆、脱墨废纸浆(DIP)。对其分别进行分散处理,抄造成纸,并对物理性能指标进行检测,对比分析不同浆种抄造滤纸的适用情况并得出结论。     

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.     

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