合成不饱和PAE树脂用作湿强剂

正陕西科技大学教育部轻化工助剂化学与技术重点实验室付小龙等人采用马来酸酐替代部分己二酸合成高固含量的不饱和聚酰胺多胺环氧氯丙烷(PAE)树脂,通过化学分析、红外光谱等手段初步研究不饱和PAE树脂的结构,并探讨马来酸酐的用量、添加方式、反应温度和保温时间等因素对不饱和PAE树脂性能的影响。结果表明,     

合成不饱和PAE树脂用作湿强剂

陕西科技大学教育部轻化工助剂化学与技术重点实验室付小龙等人采用马来酸酐替代部分己二酸合成高固含量的不饱和聚酰胺多胺环氧氯丙烷（PAE）树脂,通过化学分析、红外光谱等手段初步研究不饱和PAE树脂的结构,并探讨马来酸酐的用量、添加方式、反应温度和保温时间等因素对不饱和PAE树脂性能的影响 .     

PAE湿强树脂的合成及增强效果的研究

本研究以二乙烯三胺、己二酸、环氧氯丙烷为原料合成了高固含量、存贮稳定性较佳的PAE湿强树脂,并研究了PAE湿强树脂的增干、湿强效果以及对AKD施胶的促进作用。结果表明:以二乙烯三胺与己二酸摩尔比为2∶1时,中间体PPC树脂与环氧氯丙烷物质的量之比为1∶0.75时,PAE增湿、干强效果最佳。当PAE树脂加入到AKD乳液中的量为4∶3时,就能起到很好的AKD施胶促进效果,可以使纸张的Cobb值降到28g/m2左右。     

CMC共混改性PAE树脂的制备及应用

以二乙烯三胺、己二酸、环氧氯丙烷为原料,通过正交实验分析了反应中各因素对预聚物聚酰胺以及最终产物PAE树脂的黏度、湿强度的影响,确定出预聚体聚酰胺和最终产物PAE树脂的最优制备工艺,并结合一次回归正交设计,推导出在一定胺酸摩尔比下温度与反应时间对预聚体聚酰胺黏度的影响关系,并对此进行验证,最后将在最优工艺下所制得的PAE树脂与CMC进行共混,研究其二元增强体系,结果表明:在胺酸比1.02,反应温度180℃,反应时间4.5 h下制备的预聚物聚酰胺黏度最优;将该预聚物与环氧氯丙烷在摩尔比1:1、温度70℃下反应70 min,所制备的PAE树脂性能最优;当CMC在PAE树脂中引入量9%时,其二元增强体系效果最佳。     

聚酰胺环氧氯丙烷树脂品质控制研究

为了稳定国产PAE树脂增湿强性能,本文对PAE树脂制备过程中的工艺控制进行系统研究,以期为国产PAE树脂的质量控制提供技术依据。以二乙烯三胺、己二酸和环氧氯丙烷为原料,通过正交试验分析了制备工艺对聚酰胺品质的影响,最终确定聚酰胺树脂合成的最佳工艺,再进行烷基化反应,探究聚酰胺品质、环氧氯丙烷用量对PAE树脂品质的影响。结果显示:提高聚酰胺中间体黏度有利于增强PAE树脂增湿强性能;PAE树脂烷基化过程中,在一定程度上,环氧氯丙烷的用量增加,有利于提高PAE树脂增湿强性能,在摩尔比1:1.1时具有最佳的增湿强性能。     

聚酰胺环氧氯丙烷树脂的制备

以二乙烯三胺、己二酸和环氧氯丙烷为原料,通过正交实验分析了反应中各因素对最终产物聚酰胺环氧氯丙烷(PAE)树脂的黏度、阳离子度和湿强度的影响,进一步确定了制备PAE的最优工艺二乙烯三胺和己二酸以等量在180℃下反应120 min制备预聚体聚酰胺,再与环氧氯丙烷以等量在70℃、pH值7.0下反应70 min.在该工艺条件下可制备出高固含量、高增湿强性能的PAE树脂.     

柔软型湿强剂的合成及应用

叙述了二乙醇胺改性聚酰胺多胺环氧氯丙烷(PAE)湿强树脂的合成,分别讨论了中间体合成的影响因素和第二步反应的影响因素,并确定了湿强剂较佳的合成条件及应用条件,明显降低了产品有机氯的含量.研究表明,二乙醇胺改性PAE树脂湿强剂较佳的合成条件:n(DEA)/{n(DEA) n(DETA)}=0.2,第二步反应温度为60℃,第二步反应时间60min,n(EPI)/n(Intermediate)为0.75;湿强剂浆料中最佳添加量为1.5%,此时纸张湿强度达35%,柔软度达0.687mN.     

新型改性PAE湿强剂的合成工艺

在传统聚酰胺多胺环氧氯丙烷树脂(PAE)的基础上,经过尿素改性制得了低成本新型聚酰胺树脂增湿强剂。第一步反应为缩聚反应,形成聚酰胺预聚体:二乙烯三胺(DETA)与己二酸(AA)的摩尔比为1.1:1,反应温度为170℃左右,保温时间为200 min,预聚体PA(50%)的黏度为340 mPa·s;第二步反应为尿素改性后与环氧氯丙烷(EPI)的交联化反应:尿素用量为PA(绝干)的20%,反应浓度为30%,反应温度为60℃,环氧氯丙烷用量为PA(绝干)的40%。本研究制得的PAE添加到浆料中,搅拌30 s,利用标准纸页成型器抄纸,然后在101℃的烘箱中熟化30min后,测得加入自制PAE的纸页抗张强度保留率为24.5%左右,自制PAE不但具有增湿强效果,而且还具有抗水性。与传统PAE相比,自制改性PAE的抗水性更优。     

改性PAE-St纸张湿强剂的合成与应用

研究了接入疏水侧链聚酰胺(PAE)与环氧氯丙烷反应合成的改性PAE与苯乙烯乳液聚合制得一种纸张增强剂改性PAE-St,探讨了各步反应的物料配比、反应时间、反应温度等影响因素,确定了改性PAE-St的最佳合成条件改性PAE与St的摩尔比为12,反应温度为60℃,反应时间为6h,引发剂用量为所有单体总质量的0.3%.比较了改性PAE-St和传统PAE对纸张的增强效果,结果表明,与传统PAE增强剂相比,改性PAE-St增强纸张的干湿强度都有所提高.     

阳离子改性剂的合成及应用

以环氧氯丙烷、二甲胺和二乙烯三胺为主要原料,合成了阳离子改性剂,探讨了反应物的比例和用量、反应温度和反应时间对产品性能的影响.最佳合成工艺为:n(环氧氯丙烷)∶n(二甲胺)∶n(二乙烯三胺)=1.0∶1.0∶0.10,滴加温度控制在20~30℃,然后缓慢升温至70℃保温反应5 h.棉织物经阳离子改性剂处理后,在无盐的情况下用活性染料染色,可以达到常规染色织物的色深值(K/S值),同时还能减少染料及纯碱的用量并缩短染色时间.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.