核壳型酮肼自交联苯丙微皂乳液表面施胶剂的合成

采用半连续种子乳液聚合工艺合成了具有核壳结构的酮肼自交联苯乙烯—丙烯酸酯微皂乳液新型表面施胶剂。加入功能性单体双丙酮丙烯酰胺(DAAM)、己二酰肼(ADH)和丙烯酰胺(AM),选用乳化能力较强的非离子乳化剂OP-10和反应型的阴离子乳化剂A-2405的复合乳化剂体系,并对乳液聚合的工艺参数进行了实验研究,得到最佳反应条件为硬软单体比例3∶7,反应温度70℃,反应时间共7h,乳化剂用量6%,功能性单体用量3%,交联pH值为9。在此条件下可制得稳定、转化率高达99%的苯丙乳液。用作表面施胶剂,涂布后的纸页不仅具有优良的抗水性能,而且具有较高的光泽度。     

无甲醛聚丙烯酸酯乳液硬挺剂的制备及性能

以丙烯酸酯、苯乙烯、双丙酮丙烯酰胺和丙烯酸为单体,采用种子乳液聚合法制备了无甲醛聚丙烯酸酯乳液硬挺剂。讨论了乳化剂用量、阴/非离子乳化剂复配比、硬单体种类、软硬单体比例和双丙酮丙烯酰胺用量对硬挺剂性能的影响。结果表明:当乳化剂用量为5%(对单体质量)、阴/非离子乳化剂复配质量比为1∶2,苯乙烯为硬单体之一,软硬单体质量比为1.0∶1.4,双丙酮丙烯酰胺用量为1.5%(对单体质量),引发剂用量为1%(对单体质量)时,制备的聚丙烯酸酯乳液稳定性良好;用于棉织物硬挺整理,可以使织物抗弯长度明显增加,且具有较好的耐洗性。     

汽车工业滤纸水溶性浸渍树脂的研制

以苯乙烯为硬单体,丙烯酸丁酯为软单体,单体A和单体B为功能性单体,采用半连续乳液聚合法合成苯丙乳液,对乳液合成条件进行了研究,对乳液和浸渍后汽车工业滤纸性能进行了检测、分析。得到合成乳液最佳乳化剂用量2.0%,引发剂用量2.0%,反应温度为77℃,搅拌强度为400r·min~(-1);最佳单体的配比为:苯乙烯∶丙烯酸丁酯∶单体A∶单体B为60%∶40%∶5%∶3%;乳液平均粒径0.145μm,粒度分布均匀。浸渍后滤纸的性能指标是:耐破度320kPa,耐水性99min,透气度350L·m~(-2)·s~(-1),达到国内同类产品先进水平。     

ASA高分子乳化剂的制备及应用

以聚乙烯醇(PVA)为分散剂,苯乙烯(st)、丙烯酸丁酯(BA),甲基丙烯酰氧乙基三甲基氯化铵(DMC)和丙烯酰胺(AM)为主要单体,通过无皂乳液聚合制备了新型高分子乳化剂.用该高分子乳化剂制成ASA乳液,并对AsA乳液的稳定性和应用效果进行了研究.结果表明:当高分子乳化剂与AsA的质量比为1.5∶1时,ASA乳化效果较好;在浆内施胶过程中,当AsA乳液用量为0.8%,硫酸铝用量为1.5%,CaCO3填料用量不超过15%时较为适宜,最大施胶度可达到101s.     

有机无机杂化改性丙烯酸上光乳液的制备

采用半连续种子乳液聚合方法,并结合预乳化工艺,选用乳化剂K-12与高效乳化剂OP-10进行复配,以St、BA分别为硬软单体,DAAM、ADH和AA为功能性单体,APS为引发剂,Na HCO3为缓冲剂。在核壳反应温度分别为75℃和90℃,转速200r/min的条件下,制备出了固含量为30%的具有核壳结构和良好上光效果的苯丙乳液。通过改变乳化剂用量、反应温度、功能性单体用量、交联剂用量、保温时间,探讨其对乳液转化率,稳定性及上光效果的影响,以得到最佳的反应条件,并制得具有较高转化率和稳定性的乳液,在用作表面上光剂时可明显提高纸张光泽度。     

水性上光油的研制

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸(AA)、丙烯腈(AN)、丙烯酰胺(AAM)、丙烯酸羟乙酯(HEA)等为单体,经预乳化和种子乳液聚合法制得水性上光油.探讨了乳液聚合反应和乳液性能的影响因素,结果表明:w(复合乳化剂)为2.0%(对乳液质量),乳化剂中m(阴离子乳化剂)∶m(非离子乳化剂)质量比为1∶2,单体质量比m(MMA)∶m(BA)∶m(AN)∶m(AA)∶m(AAM)∶m(HEA)为45∶37∶6∶4∶4∶4,86~88℃反应4h制得,该乳液用于纸张的印刷上光工艺,具有光泽度佳、光滑、耐磨等特点.     

纯丙乳液聚合及应用研究

采用种子乳液聚合法合成了丙烯酸酯乳液,研究了反应时间、反应温度、乳化剂用量等因素对纯丙乳液聚合的影响;优化合成工艺为:乳化剂[m(OP-10):m(LAS)=2∶1]用量0.77%(对乳液质量),80℃滴加60 min,保温45 min.将该纯丙乳液应用于织物的涂料印花中,筛选了交联单体,讨论了焙烘时间、焙烘温度等对织物印花效果的影响,优选出最佳应用工艺:TM-200用量2.897 0%(对单体总质量),130℃焙烘180 s.在此工艺下处理的织物耐摩擦牢度、耐洗色牢度均较好.     

低温无醛聚丙烯酸酯乳液的合成及研究

采用丙烯酸酯类单体,以过硫酸钾(KPS)为引发剂并加入自制的交联单体进行乳液聚合.通过研究引发剂用量、阴-非乳化剂配比、乳化剂用量、反应温度、反应时间、交联剂用量对低温无醛聚丙烯酸酯乳液性能的影响并且确定最佳乳液合成条件:乳化剂的用量为单体总量的0.8%,阴-非离子乳化剂配比为3:4,引发剂用量为单体总量0.4%,反应温度为80～85℃,滴加时间、保温时间都为60min.     

纳米二氧化钛/丙烯酸酯复合乳液的合成研究北大核心

采用硅烷偶联剂(KH-570)对纳米二氧化钛进行表面处理,然后以过硫酸钾为引发剂,与甲基丙烯酸甲酯、甲基丙烯酸丁酯等主要共聚单体通过乳液聚合方法,合成纳米二氧化钛/丙烯酸酯复合乳液。研究了聚合温度、引发剂用量、乳化剂用量、改性纳米二氧化钛用量等对丙烯酸酯单体转化率、乳液粒径及分布等的影响。通过傅里叶红外光谱仪表征了改性前后纳米二氧化钛性能,采用透射电镜、激光粒度仪对所制备的复合乳液进行了表征。结果表明:当反应温度为85℃,乳化剂用量为5%,引发剂用量为0.5%,改性纳米二氧化钛用量为2%时,反应单体转化率高达95%以上;且乳液粒径相对较小,分布较窄。     

新型交联单体在苯丙乳液印花黏合剂中的应用

以苯乙烯为硬单体,丙烯酸丁酯和丙烯酸异辛酯为软单体,采用无皂乳液聚合方法制得无皂苯丙乳液;探讨反应型乳化剂、引发剂以及TM-200、CX-650、CM-2、T-31四种交联单体及其用量对乳液性能的影响,以及合成黏合剂的最佳使用温度。结果表明,采用反应型乳化剂和引发剂的用量均为0.8%,T-31交联单体为1.9%制备的乳液性能较好,且焙烘温度较低,节能环保。     

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