聚丙烯酰胺改善硫酸钙加填纸张PG黄染料染色效率的研究

针对纸厂生产实践中无水硫酸钙(CaSO_4)加入抄造体系后会严重影响PG黄染料染色效率的问题,本课题提出一种在浆料中加入聚丙烯酰胺进行改善的方法。探究了阳离子聚丙烯酰胺(CPAM)和两性聚丙烯酰胺(AmPAM)两种高聚物对PG黄染料染色效率的影响,其中CPAM或者AmPAM的加入均能有效提高PG黄染料的染色效率。研究表明,当CPAM添加量为0.05%或AmPAM添加量为0.06%时,PG黄染料的染色效果提高较为明显,且这两种助剂的加入均能提高填料CaSO_4的留着率。并进一步推断了2种聚丙烯酰胺对改善PG黄染料在纸张中的染色效率及无水CaSO_4填料留着率的影响机制。     

传统抄纸工艺与细小纤维预絮聚抄造工艺的对比研究

以杨木P-RC APMP为原料,对其进行筛分,研究了传统抄造工艺与共絮聚工艺下浆料悬浮液的Zeta电位、白水的阳离子需求量、细小组分的留着率以及成纸的性能。结果表明:与传统抄造工艺相比较,共絮聚工艺能提高细小纤维和填料的留着,分别提高了5.98%和6.28%;纸张的白度、不透明度和强度性能均有提高,但纸张的松厚度有所减小。传统抄造工艺下浆料的Zeta电位绝对值和白水阳离子需求量都要比共絮聚工艺条件下的高。     

纳米微晶纤维素与CPAM、CS的协同增强与助留助滤作用

研究了纳米微晶纤维素(NCC)作为增强剂和助留剂在纸业的应用。结果表明:(1)单独添加NCC对抗张强度、撕裂强度和耐破度都有一定的增强效果。(2)阳离子淀粉(CS)/NCC二元增强体系对增强纸张物理强度的效果比单独添加CS的增强效果好,且CS和NCC不同的添加方式对纸张物理强度有不同的影响。(3)单独添加NCC对纸料和填料有一定的留着效果,但并不十分明显。(4)阳离子聚丙烯酰胺(CPAM)或阳离子淀粉(CS)与NCC组成二元助留体系,对纸料和填料的留着具有协同作用,均比单独添加CPAM或CS的留着效果好。     

使用双重助留增强剂的效果

目前,国内助剂正由单一品种添加发展到采用两种或两种以上助剂的添加技术,使不同的助剂特性协同发挥作用,从而提高应用效果,现将我厂对BS双重助留增强剂的试用情况介绍于后:1 作用机理 BS双重助留增强剂助剂Ⅰ为低分子量阳离子聚电解质,助剂Ⅱ为高分子量阴离子聚电解质。当把助剂Ⅰ加入到浆料以后,阳离子聚合物分子吸附在填料和纤维表面上,通过电性作用形成微絮凝体,再加入助剂Ⅱ后,阳离子强烈地吸附阴离子聚合物,通过架桥连接使纸浆中的纤维素、填料接枝共聚,形成了粘着力强、抗剪切力的絮凝体系,从而大大提高了细小纤维和填料的留着,同时提高了纸张的物理强度。     

聚合氯化铝改性硅灰石提高填料留着率研究

研究了在硅灰石填料悬浮液中添加聚合氯化铝(PAC)对填料Zeta电位和留着率的影响。结果表明,当PAC用量为5%(相对于硅灰石)时,硅灰石填料的Zeta电位接近于0,此时硅灰石在纸张中的留着率最高;但在同时使用阳离子聚丙烯酰胺（CPAM）作为助留剂的情况下,硅灰石填料的Zeta电位接近于0时的PAC用量下的留着效果并不是最好,而是当PAC用量为1.0%~1.5%时,硅灰石在纸张中的留着效果好,并且PAC改性后的硅灰石在高得率浆中的填料留着率提高幅度比在化学浆中的大。     

造纸助剂的预混合工艺对纸张性能的影响

基于减少直接加入各种化学品繁琐的操作过程和因加填导致的纸张强度和填料留着等指标的下降,本实验通过提前预混合各种造纸化学品,然后直接用于抄纸,来改善纸张的强度和填料留着等性质。实验中将填料PCC、AKD、阳离子淀粉、CPAM、CP-3在抄纸前迅速地混合,然后加入浆料中,进行抄纸。研究结果表明:预混合合适的添加顺序为:PCC悬浮液→AKD乳液→阳离子淀粉→CPAM。各种化学品的添加量,实验中固定了AKD的用量为绝干浆的0.25%。根据实验的纸张性能检测的结果,PCC较合适用量为纸张总质量的20%,阳离子淀粉用量为绝干浆的1.5%,CPAM、CP-3的用量要根据留着和其他的纸张性质来决定。     

交联型聚丙烯酰胺的制备与应用研究

为提高新闻纸印刷适性,满足高速印刷需求,本文以丙烯酰胺、阳离子单体甲基丙烯酸二甲氨基乙酯和内烯酰氧乙基三甲基氯化铵、阴离子单体衣康酸、活性单体羟甲基丙烯酰胺、交联单体三烯丙基异三聚氰酸酯为原料,采用水溶液聚合方法,制备了中等分子量、低黏度、交联型的活性两性聚丙烯酰胺作为纸张干强剂,并对其红外、电荷密度、分子量表征。根据国内浆料和造纸现状,选用了脱墨浆料和中电导抄造体系进行应用研究,应用结果表明:在白水电导1000-1200us/cm的条件下,聚丙烯酰胺的干添加量为浆料的0.8%,纸张定量为60g/m~2,制备的干强剂可给予纸张卓越的性能和纸厂可控的成本,能提高纸张拉毛速度14%,提高纸张撕裂强度20%,增强纸张内结合力30%,浆料的滤水性能提升27%,对填料的助留性能提高了10%。     

不同助留体系对装饰原纸二氧化钛复合填料留着效果的影响

本研究分别分析了单元助留体系阳离子聚酰胺环氧氯丙烷树脂（PAE）,双元助留体系PAE/阴离子聚丙烯酰胺（APAM）、PAE/膨润土（MMT）、PAE/阳离子聚丙烯酰胺（CPAM）,三元助留体系PAE/CPAM/APAM、PAE/CPAM/MMT对装饰原纸TiO₂/滑石粉复合填料留着效果的影响。确定了各个体系的最佳添加量,并筛选出助留效果最好的助留体系。结果表明,当PAE添加量2.0%、CPAM添加量0.08%、MMT添加量0.6%时,组成的PAE/CPAM/MMT三元助留体系留着效果最佳,此时,浆料和填料留着率分别为89.5%和65.0%,纸张的不透明度、白度及匀度分别为98.5%、86.6%和91。     

填料对纸张性能的影响

分析造纸填料的性能、特点、作用,在纸张中的存在状态及抄造条件对填料和填料留着率的影响。讨论加填对纸张性能的影响,探讨纸页抄造中如何提高填料的单程留着率。     

双助留体系下预絮聚加填对纸张性能的影响

采用阳离子聚丙烯酰胺(CPAM)、皂土双组分助留体系预絮聚烷基烯酮二聚体(AKD)和沉淀碳酸钙(PCC),探究各组分添加顺序对纸张施胶效果、填料留着率及纸张物理性能的影响。对比传统加填工艺发现,采用[PCC+CPAM+皂土+CS+AKD]的预絮聚加填工艺时,纸张的物理性能提高最为明显,纸张抗张指数提高22.4%,耐破指数提高52.0%,同时,纸张的匀度指数从111.9降低至69.0,匀度显著改善。将AKD提前加入浆料中,然后采用[PCC+CS+CPAM+皂土]的预絮聚加填工艺时,纸张的施胶度和填料留着率明显提高,相比传统纸张加填工艺,Cobb_(60)值降低了24.8%,填料留着率提高了3.7%。但所有预絮聚加填工艺由于增大了PCC的颗粒大小,使得纸张白度、不透明度、透气度都有所降低。     

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