不同软硬段比例的封闭型水性聚氨酯对纸张性能的影响

研究了不同软硬段比例的聚氨酯预聚体对纸张性能的影响,探讨了不同分子质量的聚乙二醇(PEG)作为扩链剂对合成聚氨酯预聚体的影响.分别合成了由咪唑、甲苯-2,4-二异氰酸酯(TDI)和6种聚乙二醇(PEG)同系物(包括PEG200、PEG400、PEG600、PEG800、PEG1000、PEG1 500)形成的封闭型水性聚氨酯预聚体,并将其用于滤纸涂布.讨论了预聚体表面涂布量为3、5、8、10 g/m2时,滤纸各项物理性能的变化.研究结果表明,软硬段比例的变化对聚氨酯化的滤纸湿抗张指数、耐折度、撕裂指数影响规律性不明显,但是随软段比例上升,滤纸的抗张指数和挺度逐渐减小.聚氨酯化后的滤纸各项物理性能均有明显增强,以咪唑-TDI-PEC400预聚体为例,在涂布量为8g/m2时,处理后滤纸的湿抗张指数、抗张指数、耐折度、撕裂指数、挺度分别提高到原滤纸的10.7倍、2.1倍、53.6倍、1.5倍、1.3倍.     

聚氨基醇胺类染色织物耐洗色牢度提升剂的合成及应用

用3种封端剂（MDEA、DMEA、TETA）对TDI与PEG1000反应的预聚体分别进行封端，合成了3种不同结构的封闭型水性聚氨酯，讨论了封端温度对封端反应的影响并通过红外光谱测试确定了封湍反应时间，探讨了提升剂用量和焙烘温度对酸性染料染真丝绸织物耐洗色牢度的影响．     

一种新型高分子配体-聚氨酯型配体的研制

本文以甲苯二异氰酸酯(TDI)聚乙二醇(PEG)、酒石酸(TA)等为原料,合成了水溶性较好的聚氯酯型配体.讨论了加料顺序、预聚体反应时间、反应温度等对合成产物结构的影响.结果表明,TDI与TA在60～65℃反应约60min后,加入适量的溶剂1DMF稀释预聚体后,以PEG进行扩链,合成产物被碱中和后,得到水溶性较好的聚氯酯型配体.此配体易与鞣性金属配位,由IR、TGA、NMR测试的结果得到了证明.     

一种新型高分子配体—聚氨酯型配体的研制

本文以甲苯二懵氰酸酯（TDI）聚乙二醇（PEG）,酒石酸（TA）等为原料,合成了水溶性较好的聚氨酯型配体,讨论了加料顺序,预聚体反映时间,反应温度等对合成产物结构的影响。结果表明,TDI与TA在60－65℃反应约60min后,加入适量的溶剂DMF稀释预聚体后,以PEG进行扩链,合成产物被碱中和后,得到水溶性较好的聚氨酯型配体,此配体易与鞣性金属配体,由IR,TGA,NMR测试的结果得到了证明。     

有机硅改性聚氨酯抗起毛起球整理剂的合成及应用

以甲苯-2,4-二异氰酸酯(TDI)、聚酯二元醇(PDHA)为原料,合成聚氨酯预聚体;再用聚氨酯预聚体与端氨基聚硅氧烷进行反应,合成有机硅改性聚氨酯抗起毛起球整理剂。通过单因素实验优化的合成工艺为:TDI与聚酯二元醇物质的量比2.2∶1,端氨基聚硅氧烷与TDI预聚体物质的量比1.1∶1,反应温度20℃,反应时间2 h。在整理剂用量为80 g/L、浴比为1∶20、160℃焙烘90 s的工艺条件下,整理织物的经向和纬向动摩擦系数分别由0.206、0.243降至0.170、0.188,经向和纬向的弯曲刚度分别由0.369和0.133 m N·cm降至0.215和0.109 m N·cm,抗起毛起球性能提高2~3级。     

醇酯型聚氨酯油墨粘结树脂的研制

以过量的异佛尔酮二异氰酸酯(IPDI)和甲苯二异氰酸酯(TDI)的混合物与聚醚N-210反应合成端NCO基聚氨酯预聚体,用1,4-丁二醇(BDO)、1,4-环己烷二甲醇(CHDM)、新戊二醇(NPG)、异佛尔酮二胺(IPDA)对预聚体扩链,采用乙酸乙酯和异丙醇作为溶剂,合成环境友好的醇酯型聚氨酯油墨粘结树脂.研究了预聚反应中NCO与OH的比例、扩链剂的选择、交联剂、熟化时间和温度等因素对所合成的聚氨酯性能的影响,并得以确定最佳合成配方,制得光泽度优、粘附性能好、附着力强、力学性能稳定的聚氨酯油墨粘结树脂.     

封端型水性聚氨酯的合成

采用甲苯二异氰酸酯(TDI)和聚丙二醇-400(PPG-400)为原料制得聚氨酯预聚体,再以丙酮为溶剂,亚硫酸氢钠为封端剂,采用外乳化的方法,合成封端型水性聚氨酯交联剂乳液.探讨了异氰酸酯指数(R值)、预聚温度、预聚时间、封端剂用量及封端时间、乳化剂用量比例对合成效果的影响,最终得出封端型聚氨酯的最佳合成工艺.     

水溶性聚氨酯的制备及应用

以TDI、聚醚多元醇为原料，制备芳香族聚氨酯预聚体，用封端法合成了水溶性聚氨酯；探讨了影响预聚反应和封端反应的因素。在本实验范围内，以-NCO／-OH=2／1(mol比)，80～90℃反应1．5～2h制得预聚体：以异丙醇作溶剂，在促进剂存在下，以NaHSO3为封端剂，10℃，封端反应20min可制得水溶性聚氨酯。将制得的产品用于棉和丝绸的抗皱整理，可提高织物的回复角。     

封闭型水性聚氨酯预聚体乳液在纸张表面处理中的应用

用咪唑、甲苯-2,4-二异氰酸酯(TDI)和聚乙二醇600(PEG600)合成聚氨酯预聚体乳液,对纸张进行涂布处理,讨论表面涂布量分别为1.2~7g·m-2时,滤纸各项物理性能的变化。结果表明:当滤纸涂布量为7g·m-2时,滤纸的耐折度、撕裂度、抗张强度等物理性能有明显改善,处理后滤纸的湿抗张指数、干抗张指数分别提高到滤纸原纸的19.59倍和1.74倍,耐折度提高了47.05倍。扫描电镜观察可以看出加聚氨酯预聚体乳液进行聚氨酯化后,纸页的纤维间连接了许多丝状和薄膜状物质,这些物质在纤维之间尤其是纤维与纤维交叉的地方形成架桥结构,从而加强了纤维之间的连接。     

硫酸盐竹浆木素制备纸基聚氨酯复合材料

用酸析法从硫酸盐竹浆黑液中分离木素代替部分多元醇与TDI反应制备聚氨酯预聚体,再用制备的聚氨酯预聚体浸渍纸板制备纸基聚氨酯复合材料.对纸基聚氨酯复合材料的聚氨酯含量、吸水率、抗张强度、环压强度和湿强度进行了测定.结果表明,硫酸盐竹浆木素能够替代部分多元醇与TDI反应制备聚氨酯材料;纸基聚氨酯复合材料的强度性能得到很大的改善.抗张强度达300kN/m以上,湿强保留率近50%;纸基聚氨酯复合材料的最小吸水率为20.5%.     

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.     

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.     

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.     

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.