PAM特性对矿物纤维留着及纸张性能的影响

研究了不同离子类型、离子度及相对分子质量的几种聚丙烯酰胺对矿物纤维留着及纸张性能的影响。结果表明,实验所用的APAM、CPAM及AM-PAM均可提高矿物纤维的留着率和纸张的物理性能,CPAM、AM-PAM的作用效果好于APAM;其中离子度为2%、相对分子质量为1400万的CPAM比未加助剂的纸张矿物纤维留着率提高32．4%,纸张的抗张指数提高了25．6%,撕裂指数提高了11．4%;离子度为5%、相对分子质量1000万的AM-PAM比未加助剂的纸张矿物纤维留着率提高15．6%,纸张的抗张指数提高了43．8%。     

不同离子类型聚丙烯酰胺对瓦楞原纸中细小组分留着及纸张性能的影响

研究了不同离子类型的几种聚丙烯酰胺对瓦楞原纸中细小组分的留着作用以及其对纸张性能的影响.结果表明,实验所用的APAM、CPAM、及nPAM均可提高瓦楞原纸中细小组分的留着率和纸张物理性能,相对来说CPAM对瓦楞原纸中细小组分的留着作用效果好于APAM和nPAM,在CPAM添加量为0.8%时,细小组分的留着提高了13.4%;对于瓦楞原纸最重要的物理性能--环压强度来说,CPAM的效果最佳,环压强度随着CPAM用量的增加而增加,在添加量为0.8%时,环压强度提高了14.0%.     

超声波对CPAM结构性能及其对纸张增强的影响

本文以500万相对分子质量的阳离子聚丙烯酰胺(CPAM)为研究对象,利用超声波对CPAM大分子进行降解,研究超声波功率和超声波作用时间对CPAM结构性能的影响,以及不同超声波作用下的CPAM对纸张增强作用效果。研究结果表明,超声波可使CPAM大分子有效降解,CPAM溶液的黏度显著下降,Zeta电位降低,红外光谱分析认为分子中可能产生了羧基基团。超声波功率及作用时间影响CPAM对纸张的增强作用效果,在本研究范围内,300W下超声波作用14s后的CPAM对纸张的增强作用效果相对最好,当其用量为0.5%(对绝干浆)时,纸张的抗张指数、耐破指数及撕裂指数比空白样分别提高了23.4%、26.4%和14.1%。     

纸张增强剂APAM的分子质量对其增强性能的影响

以丙酮作为沉淀剂,采用逐步沉淀分级法,将相对分子质量为52.4万的APAM(聚丙烯酰胺)分为相对分子质量为65.4万、59.7万、51.6万、40.9万、28.2万的5个级分.用红外光谱和GPC对APAM进行了结构表征,并分别将这5个级分的APAM用于阔叶木浆、麦草浆和废纸浆的纸张增强,得出APAM分子质量与其提高纸张强度性能的关系.     

矿物纤维二元助留助滤体系的构建及性能研究

该文以矿物纤维、阳离子聚丙烯酰胺（CPAM）和阴离子聚丙烯酰胺（APAM）为主要原料分别构建CPAM/矿物纤维及APAM/矿物纤维二元助留助滤体系,对造纸湿部助留助滤性能、纸浆流变行为及成纸抄造性能进行了探讨.结果表明,CPAM/矿物纤维二元复配体系具有较佳助留助滤效果,且当矿物纤维的用量为0.2％质量分数（下同）时最为合适.     

原位聚合纳米SiO2法超支化CPAM的制备及其对纸张的增强作用

选用季戊四醇(PETL)为多官能团支化剂,硝酸铈铵为引发剂,甲基丙烯酰氧乙基三甲基氯化铵(DMC)为阳离子单体,与丙烯酰胺(AM)在水溶液中发生自由基反应合成支化结构的阳离子聚丙烯酰胺(BCPAM)后,再加入正硅酸乙酯(TEOS)水解原位产生纳米SiO_2,在BCPAM分子中产生物理交联,制备超支化阳离子聚丙烯酰胺(SiO_2-BCPAM),研究了其作为纸张增强剂对纸张的增强作用,通过红外光谱(FT-IR)和扫面电镜(SEM)对产物的结构和特性进行表征。结果表明,所合成的产物为SiO_2-BCPAM杂化材料;引发剂、TEOS用量和反应时间影响SiO_2-BCPAM相对分子质量或分子链的形态进而影响其特性黏度;SiO_2-BCPAM对纸张增强效果明显,当其用量为0.5%(对绝干浆)时,纸张的抗张指数、耐破指数和撕裂指数比空白纸样分别提高了23.6%、12.4%和25.5%。     

CPAM纸张增强剂合成的研究

本文以丙烯酰胺（AM）和丙烯酰氧基乙基三甲基氯化胺（ADAMQUAT）为共聚单体，通过自由基聚合反应合成阳离子聚丙烯酰胺（CPAM）。通过改变共聚单体配比及引发体系中氧化剂、还原剂用量，研究其共聚产物对纸页增强作用，并利用红外光谱、^13C核磁共振谱、凝胶渗透色谱对所合成的CPAM进行了表征。     

以季戊四醇为核分子的支化CPAM的制备及其增强效果

以季戊四醇(PETL)为聚合反应的支化剂,硝酸铈铵为引发剂,选用二甲基二烯丙基氯化铵(DADMAC)为阳离子单体,丙烯酰胺(AM)为单体,通过自由基聚合反应制备支化阳离子聚丙烯酰胺(BCPAM);利用红外光谱、13 C-NMR核磁共振谱对所合成的产物结构进行了表征;研究引发剂的用量、阳离子单体用量对产物特性黏度的影响;以BCPAM作为纸张增强剂,研究其对纸张强度性能的影响.研究结果表明,所合成的产物为BCPAM;引发剂及阳离子单体用量因影响产物相对分子质量或分子链的形态而影响其特性黏度;BCPAM对纸张增强作用显著,当其用量为0.5％时(对绝干浆),纸张的抗张指数提高了40.6％,撕裂指数提高了27.6％,耐破指数提高了12.6％.     

纸张二元增强体系的研究进展

概述了纸张二元增强体系的技术现状和研究进展,着重讨论了以阳离子聚丙烯酰胺(CPAM)、聚酰胺多胺环氧氯丙烷(PAE)、阳离子淀粉(CS)为阳离子增强剂的纸张二元增强体系,并对其增强机理作了阐述。     

PEO和CPAM对纸基摩擦材料原纸性能的影响

采用碳纤维、短切芳纶纤维、芳纶浆粕、竹纤维以及海泡石绒为原料,并用抄纸的方法抄造纸基摩擦材料原纸;通过在抄造浆料中添加聚氧化乙烯（PEO）和阳离子聚丙烯酰胺（CPAM）,探究了PEO和CPAM对浆料分散性能和纸张匀度和抗张强度的影响。结果表明,PEO对浆料有良好的分散作用,CPAM对纸张有很好的增强效果,当PEO用量为0.2%、CPAM用量为0.16%时,浆料分散效果最好,成纸的匀度最高。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press