经编间隔织物/硅橡胶柔性复合材料制备及性能研究

文章选用了5种经编间隔织物作为柔性缓冲材料的骨架，将硅橡胶作为填充料与经编间隔织物进行复合，制备具有不同填充率的柔性缓冲材料。从微观结构观察不同填充率的柔性缓冲材料中硅橡胶分布情况，并研究其静态压缩和动态冲击性能。结果表明，随着填充率的提高，柔性缓冲材料缓弹性减弱，硬度增加，承受的最大压缩载荷增强，当压缩率50%时，其压缩载荷最高可达织物的72倍。经过回归分析，可以探究结构参数对柔性缓冲材料冲击性能之间的关系和不同填充率的柔性缓冲材料所能承受最大压缩载荷量的关系。因此，填充率对柔性缓冲材料的缓冲能力有显著影响，较小的填充率能改善经编间隔织物的缓冲性能和力学性能，提高了缓压和抗冲击的能力，有利于其在防具和保护器具等领域中的应用。     

硅橡胶填充复合经编间隔织物的抗压缩疲劳性能

以表面层采用网眼结构的经编间隔织物为增强体,将两种组分的硅橡胶混合后填充到经编间隔织物的间隔层中,经固化后制成硅橡胶填充率不同的复合材料。利用万能材料试验机在不同压缩条件下分别连续反复压缩试样3 000次,并根据实验数据得到载荷和位移曲线图,对比分析不同填充率的复合材料在不同压缩条件下的抗压缩疲劳性能。实验结果表明,硅橡胶的填充率和压缩实验的压缩率对经编间隔织物的抗压疲劳性能有一定的影响。经编间隔织物本身具有较好的抗压缩疲劳性能,但载荷能力较差。经硅橡胶复合后,材料的载荷能力明显提高,变形量减少,缓弹性性能有所改善。     

经编间隔织物基柔性材料压缩性能研究

采用5种不同组织结构经编间隔织物作为增强基体,填充Natural Latex（天然乳胶）制备填充率为30%、50%、70%的柔性复合材料。对天然乳胶红外光谱图进行分析,并对纯织物及采用25%和50%压缩率的复合材料的静态压缩性进行测试。根据试验数据绘制复合材料载荷-压缩应变曲线图和应力-间隔丝排列密度关系图,对比分析不同填充率及不同压缩应变下复合材料的压缩性能。结果表明,经编间隔织物填充天然乳胶后复合材料承受载荷能力明显增加且天然乳胶填充率越高,复合材料越硬挺,抗压能力越强但缓弹性减弱;填充率越大,经编间隔织物间隔丝排列密度对复合材料压缩性能影响越小。经编间隔织物基天然乳胶柔性复合材料优良的压缩性能可应用于鞋垫或护具领域中。     

网孔型经编间隔织物压缩性能研究

选取厚度为15 mm的菱形网孔型涤纶经编间隔织物为研究对象,测试并分析其长期疲劳性、加载不同质量臀部模块时的压力分布特性以及落球回弹性。结果表明,经编间隔织物具有良好的抗疲劳性能,经2万次定载荷动态压缩后,织物厚度损失率基本趋于稳定;织物的柔软性增强了缓压能力,间隔纱能够起到支撑作用;在较小的动态冲击压力下,双层叠加经编间隔织物的平均回弹率为52.5%,织物的缓压性能较好。     

负泊松比经编间隔织物的抗低速冲击性能

为研发具有不同负泊松比效应的经编间隔织物,对5 种负泊松比经编间隔织物试样进行落锤冲击实验,通过冲击载荷与时间和位移的关系曲线分析5 种织物在低速冲击载荷下的形态变化和能量吸收性能,研究负泊松比织物在低速冲击下的能量吸收性能与负泊松比值及初始冲击能量的关系。结果表明：织物的能量吸收性能随织物负泊松比值的增大而提高,织物的能量吸收性能越好,耐冲击性能也越好;初始冲击能量的大小也会影响织物的能量吸收速率和耐冲击性能,初始冲击能量越高,织物的耐冲击持久性越差,但对织物总的能量吸收影响不大。     

膝盖防护用材料动态缓冲性能研究

为研究老年人摔倒时膝盖部位的防护装置,探讨经编间隔织物和聚氨酯海绵的动态缓冲性能。采用改进后的动态冲击方法模拟老年人摔倒时的受力情况,通过分析接触刚度系数,冲击力与位移曲线,冲击力与时间曲线,以及冲击能量与时间曲线反映材料的动态缓冲性能。此外,通过定义缓冲系数进一步表征试样缓冲性能,并分析试样的结构参数和缓冲系数之间的关系。结果表明,一定硬度的聚氨酯海绵具有较好的能量吸收性能,通过聚氨酯海绵和经编间隔织物的复合可得到缓冲性能较好的材料。     

新型纬编间隔织物及其复合材料的冲击性能

开发了一种双层V形(三角形)间隔层纬编间隔织物(WKSF)编织工艺，并在STOLL电脑横机上编织双层V形与双层U形WKSF,分别研究了两种织物的横向和纵向断裂拉伸性能。通过试验得到拉伸载荷-位移曲线。结果表明，双层V形间隔结构织物的横向拉伸性能优于双层U形间隔结构。同时研究了浸渍剪切增稠液(STF)的WKSF(STF-WKSF)冲击行为。通过冲击载荷-位移与能量吸收-位移曲线可知，在相同的冲击速度下，STF-WKSF比纯WKSF具有更低的峰值力和更高的能量吸收，STF可以有效提高织物的抗冲击性能；在不同的冲击速度下，双层V形结构的STF-WKSF比双层U形结构具有更好的缓冲性能。双层V形STF-WKSF可以用作人体局部缓冲保护材料。     

衬垫用经编间隔织物的压陷性能

为获得具有良好支撑性和压力分布的衬垫用经编间隔织物,对不同规格的经编间隔织物的压陷性能进行研究。在双针床拉舍尔经编机上,通过改变织物纵密、间隔丝垫纱角度、间隔丝直径以及脱圈板距离,试织了13种经编间隔织物试样。测试了试样的压缩应力与应变曲线,并以25%和65%压陷硬度和支撑因子作为评价织物压陷性能的指标。探讨间隔丝密度、垫纱角度和直径以及织物厚度对经编间隔织物压陷性能的影响。研究结果指出：织物屈服阶段是研究织物压缩性能的重要阶段;通过各种结构参数的合理配置,可以获取具有理想压缩特性的经编间隔织物衬垫材料。     

经编贾卡提花间隔织物的顶破性能

为探讨不同经编提花间隔织物结构的顶破性能差异,采用在拉舍尔双针床贾卡经编机上编织的8种不同提花结构的织物进行顶破性能试验,分析不同织物的顶破强力大小和顶破曲线特征,解释了经编间隔织物的顶破机制,并从提花面结构角度讨论对织物顶破强力的影响。结果表明：平布层和提花层分别影响间隔织物顶破过程的第1、2阶段;间隔层结构决定间隔织物顶破高度;提花面结构决定间隔织物顶破强力大小,厚组织顶破强力大于薄组织,顶破强力与网孔尺寸成反比关系;在鞋用经编提花间隔织物的设计中,可根据鞋面部位和功能需求进行灵活的组织搭配,丰富鞋材的花纹图案。     

三维间隔织物轻质复合材料的力学性能

将3D间隔织物与轻质聚氨酯相结合,制备出3D经编间隔织物复合材料。对不同基体密度与增强体规格的3D间隔织物复合材料进行三点弯曲测试,研究其结构参数对力与位移曲线的影响;并对其抗冲击性能进行评价,获取影响复合材料冲击防护性能的因素。结果表明：基体密度对三维间隔织物复合材料力学性能的影响十分显著,基体密度越大,3D经编间隔织物复合材料的弯曲应力和弯曲强度越大,抗弯曲能力也越强,而可塑性越差,柔韧性越差;冲击吸收的冲击力逐渐减少,导致复合材料的抗冲击恢复性越差。     

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.     

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.     

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.     

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.