自交联苯丙乳液的无皂聚合及其结构与表面施胶性能

以N-羟甲基丙烯酰胺作自交联单体,聚乙烯醇(PVA)为高分子分散稳定剂,采用无皂种子聚合制备了稳定的自交联苯丙乳液.当软硬单体比例n(BA)/n(st)=1.0,w(PVA)=6%,w,(ODA)=10%,w(NMA)=6%时,自交联苯丙乳液具有优异的施胶效果,当用质量分数为1%的苯丙乳液进行表面施胶时,纸张施胶度可达43.0 s,表面强度达3.2m/s,耐折度88次,环压指数达7.38N-m/g;苯丙乳液与淀粉有良好的适配性,并可取得优异的复合施胶效果.通过动态激光粒径分析(DLLS)、差示扫描量热(DSC)等对乳液粒径及其分布和共聚物热转变性能及微相结构进行了表征.     

自乳化苯丙乳液对装饰原纸表面施胶的工艺研究

为提高装饰原纸的表面强度和印刷适性,使用自制自乳化苯丙乳液（SAE）与淀粉或聚乙稀醇（PVA）施胶液复配对装饰原纸进行表面施胶。重点考察了施胶液种类、黏度、与SAE配比以及施胶量等因素对表面施胶效果的影响,同时对比了自制SAE与市售SAE处理效果的不同。结果表明,选择糊化淀粉为施胶液,淀粉黏度70 mPa·s,降解淀粉所需过硫酸铵（APS）用量2.2%,淀粉与自制SAE配比20∶1,施胶量为2 g/m2时,经表面施胶后的装饰原纸表面性能和印刷适性优良;淀粉与自制SAE复配能将装饰原纸的印刷表面强度提高4.4倍;自制SAE比市售SAE对装饰原纸的施胶效果更优。     

阳离子型苯乙烯-丙烯酸酯共聚物的表面施胶性能

用Cobb值测定仪考察了苯乙烯（ST）丙-烯酸丁酯（BA）二-甲基二烯丙基氯化铵（DA）共聚物乳液（简称苯丙乳液）的表面施胶性能。实验结果表明,当DA占单体总质量的7%、m（ST）∶m（BA）=5∶3时,苯丙乳液的表面施胶性能较佳,纸页Cobb值为28.3 g/m^2,环压指数提高20%;苯丙乳液与w（交联剂）≤1%共混后进行表面施胶,纸页Cobb值达18.1 g/m^2。     

阳离子型苯丙乳液与阳离子分散松香施胶剂的协同作用

考察了阳离子型苯丙乳液在含质量分数为10%的碳酸钙抄纸体系中对阳离子分散松香施胶剂的增效作用。实验结果表明,阳离子苯丙乳液与阳离子分散松香施胶剂的质量比为9：1的混合乳液的施胶度（60s）远大于等量阳离子分散松香施胶剂时的施胶度（14s）,而阳离子型苯丙乳液单独使用时没有施胶作用。阳离子型苯丙乳液增大了阳离子分散松香施胶剂的表面电荷密度和疏水性。     

PVA接枝共聚物乳液表面施胶剂的研究

以PVA为主链,丙烯酸(AA)、苯乙烯(St)、丙烯酸丁酯(BA)为单体,通过直接滴加方式制备了一种无皂乳液表面施胶剂。讨论了反应条件的变化对乳液稳定性及施胶应用效果的影响,确定了较佳的合成条件为:m(AA)∶m(St)∶m(BA)=4∶12∶9,w(KSP)=2.5%,反应温度80℃,反应时间6h。在原料相同的情况下,用直接滴加方式制得的PVA接枝乳液和利用核壳技术制得的苯丙乳液进行了理化性能和施胶性能的对比,结果发现,PVA接枝乳液的乳胶平均粒径比核壳苯丙乳液的小,且施胶效果明显比核壳苯丙乳液的好。     

自乳化苯丙乳液对装饰原纸表面施胶的工艺研究

为提高装饰原纸的表面强度和印刷适性,使用自制自乳化苯丙乳液(SAE)与淀粉或聚乙稀醇(PVA)施胶液复配对装饰原纸进行表面施胶。重点考察了施胶液种类、黏度、与SAE配比以及施胶量等因素对表面施胶效果的影响,同时对比了自制SAE与市售SAE处理效果的不同。结果表明,选择糊化淀粉为施胶液,淀粉黏度70 mPa·s,降解淀粉所需过硫酸铵(APS)用量2.2%,淀粉与自制SAE配比20∶1,施胶量为2 g/m2时,经表面施胶后的装饰原纸表面性能和印刷适性优良;淀粉与自制SAE复配能将装饰原纸的印刷表面强度提高4.4倍;自制SAE比市售SAE对装饰原纸的施胶效果更优。     

几种不同施胶剂施胶性能对比

用改性胶原蛋白乳液、苯丙乳液和AKD乳液三种胶液对瓦楞原纸进行表面施胶,对比考察三种施胶剂施胶后纸张的力学性能及吸收性变化。将改性胶原蛋白乳液与苯丙乳液进行复配施胶,当两者的比例为1：1时,此时纸张的各项性能最好,与未施胶纸样相比,纸张的抗张指数、环压指数分别提高了63.4%和79.2%,Cobb60降至40 g/m2。改性胶原蛋白乳液与AKD乳液复配施胶,两者的比例为3：1时,纸张的各项性能最好,纸张的环压指数、抗张指数分别提高了54.2%和47.7%。纸张Cobb60值则降为34.7 g/m2。将三种胶液与淀粉复配,或者两两复配施胶,其中以改性胶原蛋白乳液与苯丙乳液复配后效果为最佳。     

淀粉接枝苯丙无皂共聚物乳液的制备与表征

以芬顿试剂为引发剂,木薯淀粉为主链,苯乙烯（St）、丙烯酸丁酯（BA）、松香、甲基丙烯酸二甲基氨基乙酯（DM）和N-羟甲基丙烯酰胺（NMA）为单体,采用无皂乳液聚合法在木薯淀粉分子上接枝苯丙共聚单体,合成出一种苯丙无皂乳液表面施胶剂,并通过傅里叶变换红外光谱仪、热重分析仪、粒径分析仪、静态接触角和扫描电镜对乳液的结构和性能进行了表征。结果表明,在淀粉用量10%、m(单体总量)∶m(淀粉)=2∶1、H₂O₂用量5.0%、m(St)∶m(BA)=3∶1、松香用量0.8%、DM用量1.2%、NMA用量0.2%条件下,合成了苯丙无皂乳液表面施胶剂;当其用量为淀粉施胶液的0.4%时,施胶度为46 s,纸张环压指数为5.47 N·m/g。     

苯丙微乳液的制备及其在表面施胶剂中的应用

本文利用半连续种子乳液聚合法合成苯丙乳液,并将其制备成表面施胶剂应用于纸张施胶中。实验发现:反应温度为85℃,单体总量所占的比例分别为:w(St)=36.7%,w(BA)=41.8%,w(MMA)=18%,w(AA)=2%,w(NaHCO3)=0.4%,w(APS)=0.5%,w(N-MA)=0.3%时,苯丙乳液稳定性和粒径大小最佳。所得的乳液固含量为32.3%,粒径为107nm,凝胶量为0.08%,吸水率为3.7%,具有良好的粒子稳定性和机械稳定性。与淀粉、PVA、市售两种苯丙乳液制得的表面施胶剂相比,自制的苯丙微乳液可赋予纸张更为良好的表面性能,施胶后纸张抗张强度可达61N·m/g,表面强度可达3.52m/s,施胶度可达215s。     

松香苯丙乳液的混合表面施胶

研究了松香苯丙聚合乳液的施胶效果。结果表明:添加松香的两种自制表面施胶剂施胶效果均好于工业国产施胶剂,其中添加20%松香的表面施胶剂效果更好,优于进口工业表面施胶剂;实验还表明:用添加松香的表面施胶剂施涂后,纸的抗张强度和环压强度提高;施涂量超过1g/m2以后,施胶液膜的防水性变化不大。     

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