KH550改性对微纳纤维素/聚乳酸复合3D打印材料性能的影响

为提高微纳纤维素（MNC）与聚乳酸（PLA）复合材料的性能,将分散于二氯甲烷的MNC与溶解于二氯甲烷的PLA 通过溶液共混法进行复合,成功制备了适用于FDM型3D打印机的MNC/PLA复合3D打印线材。采用硅烷偶联剂KH550对MNC进行改性,考察了KH550用量对MNC的晶型结构及对MNC/PLA复合材料断面形态和机械性能的影响,进一步研究了KH550改性MNC对MNC/PLA复合材料3D打印性能的影响。结果表明,溶液共混法制备的MNC/PLA复合3D打印线材可在保持复合材料机械性能的基础上将高含量的MNC与PLA均匀复合;1%用量（相对于MNC绝干质量）的KH550可改善复合材料的界面相容性且复合材料的机械性能最佳;制备的MNC/PLA复合3D打印线材经FDM型3D打印机可成功打印出3D打印产品。     

玉米淀粉-聚乙烯醇复合薄膜生产工艺研究

以玉米淀粉和聚乙烯醇为基本成膜物质,添加适宜助剂,对其成膜特性进行了系统研究.通过单因素试验,研究了玉米淀粉质量浓度、聚乙烯醇质量浓度、增塑剂甘油体积分数和交联剂戊二醛体积分数对玉米淀粉-聚乙烯醇复合薄膜性能的影响,在单因素试验基础上进行了L9(34)正交试验,确定了玉米淀粉-聚乙烯醇复合薄膜最佳工艺参数.试验结果表明:在6.5 g/mL玉米淀粉和3.5 g/mL聚乙烯醇溶液中添加4.0%甘油和0.6%戊二醛,100℃水浴下交联反应25 min,刮膜后70～90℃恒温干燥45 min,所得到的可降解薄膜不仅呈现良好的外观,而且具有良好的抗张强度、伸长率和透光率,其抗张强度达27.18 MPa,伸长率达309.5%,透光率为51.97%.     

酸碱处理对超高相对分子质量聚乙烯纤维纸性能的影响

采用湿法成形工艺制备了超高相对分子质量聚乙烯(UHMWPE)纤维纸,并分析了不同酸、碱处理条件对UHMWPE纤维纸性能的影响。结果表明,随着酸、碱质量分数及相应处理时间的增加,UHMWPE纤维纸的抗张强度保留率呈现下降趋势,质量分数30%H_2SO_4和质量分数20%NaOH分别处理6 h后,UHMWPE纤维纸抗张强度保留率均在90%以上,处理48 h后,UHMWPE纤维纸抗张强度保留率保持在80%以上,且质量分数30%H_2SO_4处理48 h后UHMWPE纤维纸被氧化出现了羰基、羟基等活性基团,质量分数20%Na OH处理48 h后活性基团出现不明显,表明酸处理更适合做UHMWPE纤维纸的改性处理。     

白泥纤维的软化改性及其对配抄纸张性能的影响

针对白泥纤维脆性大的特性,合成了PVA-KH560软化剂;采用傅里叶红外光谱仪对软化剂进行了表征;利用此软化剂对白泥纤维进行软化改性,并通过扫描电镜等方法分析纤维的软化改性效果;再将软化前后的白泥纤维分别与植物纤维进行配抄,测定白泥纤维对纸张性能的影响。并探讨不同浓度羧甲基纤维素纳（CMC）对纤维的分散及纸张的增强作用。结果表明,随白泥纤维用量的增加,纸张抗张强度、环压强度均降低;CMC最佳分散浓度为0.8%（质量分数）;用此分散纤维配抄纸张性能比未进行分散的明显提高,当添加30%改性纤维时,纸张抗张指数提高了40%,环压指数提高了42%。     

增强增韧聚乳酸纤维的制备及其性能

为增强增韧聚乳酸纤维,采用聚酰胺（PA）与聚乳酸（PLA）制备了PLA/PA 共混纤维,并对其热学性能、结晶、热稳定性、PA 的分散性以及PLA/PA共混纤维的力学性能进行了研究。研究结果表明：PA的加入对PLA 的玻璃化转变温度及熔融温度没有显著影响,但改善了PLA的结晶行为,结晶度提高了51.6%;PLA 热稳定性随着PA 含量的增加而提高;PA在PLA 中分散均匀;随着牵伸倍数的增加,PLA/PA 共混纤维的取向度提高,力学性能得到改善,当牵伸倍数从1.5增加到3.0 时,取向度提高了30.88%,同时纤维的断裂强度提高了48.58%;当ＰＡ 质量分数为1%和20%时,PA/PLA共混纤维的断裂强度分别提高了8.6%和25%,断裂伸长率分别提高了10.9%和55.9%。     

转谷氨酰胺酶改性明胶高强度薄膜的制备

在研究制备转谷氨酰胺酶（mTG）改性明胶可食性薄膜工作的基础上，通过在成型工艺中进一步采用室温干燥和湿态二次定向处理的方法，获得了抗张强度达18．3MPa，韧度达8．4J／cm^2的可食性明胶薄膜。在配料中添加质量分数2％的聚乙烯醇（PVA）并采用相同的成型工艺，所制备明胶薄膜的机械性能得到进一步提高。生物降解性实验表明，在被质量分数0．5％的Alcalase碱性蛋白酶作用4h后，不含PVA的可食性明胶薄膜的降解率可达99．2％，含PVA明胶薄膜的降解率也达到了97．5％。     

谷氨酰胺转氨酶对大豆蛋白／PVA 复合薄膜性能的影响

以大豆蛋白和聚乙烯醇（ PVA）为主要原料,以抗张强度、断裂伸长率、透光率、吸水率为评价指标,通过单因素试验和正交试验,研究了谷氨酰胺转氨酶（简称TG）对大豆蛋白/PVA复合薄膜性能的影响。试验结果表明：当反应pH为5．0,反应温度为55℃,TG添加质量分数为0．20‰时得到性能最佳的复合薄膜;在最佳条件下,薄膜的抗张强度、断裂伸长率、透光率和吸水率分别为8．06 MPa,89．97％,30．8％和46．43％。     

热固性湿增强剂KH 560／PAE的制备及其对纸张的增强性能

制备了γ-环氧丙氧基丙基三甲氧基硅烷（KH 560）改性的PAE,讨论了其合成的影响因素;并采用羧甲基纤维素钠（CMC）作助留剂和改性PAE同时应用于纸张抄造。结果表明,n（NH2）：n（COOH）=1．05,n（EPA）：n（EPI）=1．5,w（KH560）=12％,合成温度为70℃,初始浓度为25％质量分数,此改性PAE反应过程易于控制,且有优良的湿强效果。     

TiO2-Ag/聚乳酸纳米复合纤维的制备及其抗菌性能

为赋予聚乳酸(PLA)纤维高效的抗菌性能,采用熔融共混纺丝法分别制备了不同质量配比的二氧化钛接枝银纳米介孔微球(TiO₂-Ag)/PLA纳米复合纤维和一定组成的TiO₂/PLA纳米复合纤维,并对2种纤维的结构、热性能和抗菌性能等进行表征和分析。结果表明:当TiO₂-Ag和TiO₂这2种纳米粒子添加质量分数不超过3%时,可在PLA基体中较均匀地分散;2种粒子的加入均不影响PLA的玻璃化转变温度和结晶结构,但会使其熔融温度和热稳定性下降,加入质量分数为3%的TiO₂后,导致PLA的结晶温度略有下降;随着TiO₂-Ag质量分数的增加, TiO₂-Ag/PLA纳米复合纤维对金黄色葡萄球菌和大肠杆菌的抑菌率不断增加;添加相同量的2种纳米粒子时,TiO₂-Ag/PLA复合纤维对2个菌种的抑制效果明显优于TiO₂/PLA复合纤维。     

还原氧化石墨烯增强聚乳酸纳米纤维膜的制备及其性能

针对静电纺聚乳酸(PLA)纳米纤维膜力学强度不高的问题,将一定质量的还原氧化石墨烯(rGO)分散于PLA和二甲基甲酰胺(DMF)纺丝溶液中,通过静电纺丝法制备PLA/rGO复合纳米纤维膜。对纺丝液的流变性能以及复合纳米纤维膜的形貌结构、微观结构和力学性能进行分析,采用四唑盐比色法对复合纳米纤维膜的细胞相容性进行表征。结果表明:rGO成功地复合至PLA纳米纤维中,且以不规则球状形式分布于PLA纳米纤维膜中;rGO的复合显著提升了PLA纳米纤维膜的力学强度,当rGO质量分数为0.6%时,复合纳米纤维膜的断裂强度达2.02 MPa,是纯PLA纳米纤维膜2.3倍;培养1、3和7 d后,小鼠胚胎成骨细胞可在复合纳米纤维膜上生长和增殖,表明PLA/rGO复合纳米纤维膜具有较好的细胞相容性。     

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