木素用于酚醛树脂胶黏剂改性

采用酸析法回收得到的木素为原料,替代部分苯酚与甲醛反应制备木素改性酚醛树脂胶黏剂,并测定其固含量、动力黏度(40℃)、游离甲醛含量和胶合强度等性能。主要考察了木素/酚化木素掺入比例、催化剂(碱)种类及用量、酚醛摩尔比以及反应温度对胶黏剂性能的影响。结果表明,合成木素酚醛树脂胶黏剂较佳的工艺条件为:木素掺入比例5%～15%(质量百分数,以苯酚质量为基准),酚醛摩尔比1:1.5,催化剂为NaOH,加入量0.6%(质量百分数,以苯酚质量为基准),反应时间3h。采用酚化木素时,掺入比例可达45%,制得胶黏剂性能优于纯木素。木素替代部分苯酚改性酚醛树脂胶黏剂,不仅可以降低生产成本,而且更环保。     

水稻秸秆基木质素改性酚醛树脂胶黏剂的制备与性能

针对酚醛树脂胶黏剂的游离醛、酚含量高及生物降解性差的缺点,采用粮食加工废弃物-水稻秸秆中的木质素为原料,取代一部分苯酚作为反应物,并以游离苯酚含量、游离甲醛含量、产品粘度和胶合强度为指标研究甲醛添加量和尿素添加量对合成的木质素改性酚醛树脂胶黏剂的性能影响。经条件优化后,合成出性能优良、环保秸秆基木质素改性酚醛树脂胶黏剂。本研究既为改性酚醛树脂的研究提供可行性方案,也使水稻秸秆这种废弃物的回收再利用成为可能。      

制浆黑液在酚醛树脂胶黏剂中的应用

制浆黑液中的降解木质素含有酚羟基结构,可以替代部分苯酚制备酚醛树脂.以NaOH为催化剂,采用二次缩聚法制取酚醛树脂胶黏剂.实验表明,当黑液添加量为15%时,胶黏剂的黏度比空白实验增加1倍,游离甲醛含量降低了27%,胶合强度提高了13.2%.红外光谱分析表明,黑液中的木质素与游离甲醛反应生成有羟甲基的物质,该物质能与酚醛树脂胶粘剂中的物质发生反应,从而既降低了甲醛含量又提高了胶黏剂的胶合强度.     

碱木素／尿醛树脂胶黏剂的合成研究

利用制浆黑液中的碱木素为主要原料,经过羟甲基化改性,甲醛缩合制备纤维板胶黏剂,探索改性木素胶黏剂粘结效果。用正交试验方案设计对碱木素改性、胶黏剂制备工艺进行优化。研究表明：将碱木素进行羟甲基化改性,其活性明显提高。最佳的优化条件：甲醛用量7mmol·g-llignin,pH值10,反应温度70℃,反应时间120min;改性碱木素最佳的加入量比例为20％。用碱木素制备改性木素胶黏剂可利用造纸黑液木素资源,而且具有广泛的应用前景。     

黑液木素制备酚醛树脂胶黏剂的研究进展

木素与酚醛树脂结构相似,可代替部分苯酚制备酚醛树脂胶黏剂。通过对木素胶黏剂的研究现状的系统归纳,介绍了黑液木素制备酚醛树脂胶黏剂的两种方式:一是木素直接替代苯酚,二是木素经活化后再与酚醛树脂结合。合理地利用造纸废液中的黑液木素不仅可以有效地处理大量的造纸黑液,而且可以降低酚醛树脂胶黏剂的生产成本,产生可持续发展的经济效益。     

一种新型酚化木质素胺乳化剂的合成及其性能

以苯酚改性硫酸盐木质素得到了酚化木质素,再将其与脱氢枞酸单乙二酰胺、甲醛进行Mannich反应以引入脱氢枞酸单乙二酰胺甲基亲油基团,然后将反应产物进一步与二乙烯三胺、甲醛反应引入了二乙烯三胺甲基亲水基团,合成了一种新型酚化木质素阳离子乳a化剂。实验表明,在碱性条件下,当 n(苯酚)∶n(木质素)=1∶1、反应温度100℃、反应时间1.5 h时,所得产物酚化木质素的酚羟基含量较木质素增加了30.3%,相当于每个C9单元接枝了0~30个苯酚分子,质均分子质量增大7%,多分散性由1.49降至1.29;与木质素相比,酚化木质素中引入的脱氢枞酸单乙二酰胺甲基数量增加了1.1倍,引入的二乙烯三胺甲基数量增加了0.42倍;在pH值为2的稀盐酸溶液中,所合成的脱氢枞酸单乙二酰胺/二乙烯三胺/甲醛改性酚化木质素阳离子乳化剂的最大Zeta电位为38.0 mV,质量浓度为10 g/L时,表面张力为35.0 mN/m,甲苯乳液油水分层时间为70 min,均优于用未经酚化改性的木质素合成的产物。     

木质素改性氧化淀粉胶黏剂的制备与探索

探讨高碘酸钠氧化的木薯淀粉与苯酚复合制备胶黏剂的正交优化方案,并以此为基础研究酚化木质素代替苯酚与氧化木薯淀粉反应的情况。研究结果表明,当氧化时间为240min,氧化温度为35℃,高碘酸钠与木薯淀粉用料比为0.8∶1.0,苯酚与木薯淀粉质量比为1.0∶1.0时,所制备的胶黏剂干胶合强度最佳,达到2.631MPa,影响的因素主次为苯酚质量比>氧化温度>氧化时间>高碘酸钠用料比;经酚化处理后的木质素能够代替部分苯酚制备胶黏剂,随着木质素替代率的升高,其胶黏剂干胶合强度呈下降趋势。傅里叶变换红外光谱(FT-IR)表征分析结果表明,经过高碘酸钠氧化,木薯淀粉出现了醛基,氧化后的木薯淀粉与苯酚和酚化木质素发生了反应。证明用木质素部分替代苯酚制备胶黏剂具有可行性,这有助于减少来源于化石燃料的苯酚的消耗,为制备环保的胶黏剂提供了思路。     

改性豆基蛋白质胶黏剂用于杨木胶合板生产初探

利用碱对豆粉进行处理,使蛋白质水解成为低聚肽,低聚肽进一步与甲醛反应生成稳定的蛋白质.这种物质可与苯酚和甲醛反应生成改性豆基蛋白质胶黏剂.采用单因素试验方法.对改性豆基蛋白质胶黏剂压制杨木胶合板的生产工艺进行了探讨.经过生产性试验证明,利用这种胶黏剂压制的胶合板的强度和抗水性可以和商业酚醛胶黏剂相媲美.这种胶黏剂豆粉的含量为63%,因而可以大幅减少木材胶黏剂用苯酚的量.     

毛竹木质素酚与碱木素在羟甲基化改性上的比较研究

本实验对毛竹碱木素和毛竹木质素酚分别进行羟甲基化改性,并改变木质素和甲醛反应比例进行对比实验,通过红外光谱法(FT-IR)、凝胶渗透色谱法(GPC)和二维核磁(2D-HSQC NMR)等分析手段对羟基化改性前后的毛竹碱木素和毛竹木质素酚进行表征,发现在改性前两者几乎相同的分子量特征下,改性后相比于碱木素,木质素酚重量平均分子量和分散比变化明显,说明相同反应条件下木质素酚发生羟甲基化的位点多,效果优于碱木素;保持甲醛用量不变,随着木质素酚用量加大,其羟甲基化效果增强。     

化学改性在木素基酚醛树脂胶黏剂制备中的研究进展

综述了木素磺酸盐、碱木素、酶解木素等应用于改性酚醛树脂胶黏剂的发展现状,以及几种常用于提高木素反应活性的化学方法,分析木素改性酚醛树脂存在的问题并对其应用前景进行了展望。     

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