碱回收白泥精制碳酸钙对AKD施胶剂的吸附特性研究

用紫外分光光度法和颗粒电荷滴定法测定了几种碱回收白泥精制碳酸钙(LMCC)和商品碳酸钙(包括PCC1、PCC3、GCC1和GCC2)填料对AKD施胶剂的吸附特性。结果显示,LMCC和GCC1对AKD的吸附量高于实验用其他商品碳酸钙,GCC1的比表面积远低于LMCC,但其AKD吸附量却高于LMCC,这可能与填料的电荷特性密切相关。LMCC加填后成纸的施胶度最差,且随干燥温度的增加LMCC对AKD施胶的负面影响增加,AKD吸附量最高的GCC1加填纸的施胶度远高于LM-CC加填纸,这与通常所认为的吸附量越高的填料对AKD施胶的影响越大相矛盾,有可能LMCC对AKD施胶的影响并非单纯的吸附原因。     

草浆白泥加填特性的研究

研究取自不同厂家白泥碳酸钙的基本物化特性和加填应用性能,并将其与商品沉淀碳酸钙(PCC)和研磨碳酸钙(GCC)填料进行性能对比。实验结果表明,碱回收白泥精制碳酸钙的活性氧化钙和残碱含量与商品碳酸钙相当,但其白度和碳酸钙含量低,杂质含量高。白泥碳酸钙具有较高的比表面积,白泥颗粒呈不规则状且粒径分布较宽,其表面带负电而且具有较高的电导率。白泥加填后成纸的光学性能介于商品PCC与GCC之间,强度性能与商品碳酸钙相当,且白泥加填具有较高的留着率,但是白泥对AKD施胶会产生明显的负面影响,要达到常规填料的施胶度水平,白泥加填纸对AKD的消耗量是商品碳酸钙的2倍甚至更高。     

白泥碳酸钙加填纸中AKD施胶剂的迁移及抑制研究

探讨了AKD施胶剂的迁移及抑制其迁移过程对白泥碳酸钙加填纸施胶性能的影响。结果表明,与商品轻质碳酸钙填料相比,白泥碳酸钙对AKD的吸附能力高,使得纸张干燥过程中更多的AKD熔融渗透至白泥碳酸钙填料孔隙内部即AKD的迁移,这部分迁移的AKD是导致白泥碳酸钙加填纸施胶效率低的主要原因;阳离子淀粉可抑制白泥碳酸钙填料与AKD之间的静电吸附或者封闭白泥碳酸钙表面的孔隙,有效抑制白泥碳酸钙加填纸中AKD的迁移,提高加填纸的AKD施胶效率。     

淀粉改性碳酸钙填料对改善纸张性能的研究

利用淀粉与硬脂酸钠形成复合物同时添加淀粉交联剂对沉淀碳酸钙(PCC)进行覆膜改性。比较了改性PCC加填与传统加填的使用效果,研究了改性PCC在不同加填量下对纸张施胶性能和纸料留着率的影响。结果表明:在灰分相同时,改性PCC加填的纸张性能要明显好于未改性PCC加填的纸张;在相同添加量和相同AKD用量下,改性PCC加填的纸张的施胶效果好于未改性PCC加填的纸张。在相同的填料添加量时,改性PCC加填的留着率高于未改性PCC加填。     

镁铝水滑石用作造纸填料对AKD施胶效果的影响

考察了镁铝水滑石(HT)用作造纸填料对AKD施胶效果的影响,结果表明,工业级HT对AKD的施胶效果有较大影响.随着HT用量的增加,AKD的施胶效果迅速降低,直至加填纸无疏水性能,HT加填纸的吸水性(Cobb值)会随着AKD用量的增大而减小,HT用量为10%、AKD用最为0.4%时,HT加填纸的吸水性降至30 g/m2.此外,还考察了自制的不同镁铝比HT及镁铝比为5:1型不同层间阴离子的HT作为填料对纸张施胶性能的影响.结果表明,自制HT加填纸的吸水性均在14～17 g/m2之间,其中SO2-4-HT对AKD施胶效果的影响与PCC的相似.     

CPAM-膨润土双元体系在新型硅酸钙加填纸上的应用

比较分析了CPAM-膨润土双元微粒助留体系对新型硅酸钙(FACS)和研磨碳酸钙(Gcc)加填浆料的留着、滤水及纸张性能的影响.实验结果表明,CPAM-膨润土双元体系应用于FACS加填纸中时,CPAM需求量高于GCC加填的;膨润土用量为0.1％时,CPAM用量的增加,能改善FACS加填纸料的留着性能,但对其滤水性能却有不利影响;CPAM用量为0.08％时,随着膨润土用量的增加,FACS加填纸料Zeta电位的下降比GCC加填的更快;膨润土的用量低于0.2％时,膨润土用量的增加对纸料的首程留着率和滤水性能都有利.CPAM用量为o.08％、膨润土用量为0.1％时,FACS加填纸白度与GCC加填纸张相当,但是不透明度比GCC加填纸高;FACS加填纸的抗张指数比GCC加填纸低11.2％,撕裂指数比GCC加填纸低21.0％;FACS加填纸张的松厚度比GCC加填纸高41.7％.加填纸张的扫描电镜对比发现,FACS能够较好地填充在纤维之间的缝隙中,可以看到纤维与填料之间有较好的交织.     

研磨碳酸钙的胶乳改性及其在加填纸中的应用

采用胶乳对填料级研磨碳酸钙(GCC)进行表面改性,对改性GCC的基本性能及其加填性能进行了研究。结果表明,采用胶乳对GCC进行表面改性时,胶乳在GCC表面的吸附率超过了99%;经过胶乳改性后,填料的白度略有降低,填料平均粒径虽然变大但粒度分布变窄;与未改性GCC相比,改性GCC加填纸的强度性能得到明显提高,在胶乳用量为2.0%(对GCC)、保持纸张强度性能不变条件下,纸张灰分含量从15.8%提高到31.1%,同时光散射系数得到明显改善;且改性GCC可明显提高纸张的施胶性能。     

白泥碳酸钙特性及其加填纸AKD施胶效率研究

探讨了作为填料的白泥碳酸钙(CCC)的晶型结构及不同晶型结构CCC加填对AKD施胶效率的影响原因及机理。实验结果表明,在灰分基本相当的情况下,具有规则晶型(纺锤状和针状)结构的CCC加填纸的AKD施胶效率明显优于不规则晶型结构的CCC加填纸;不规则晶型结构的CCC的比表面积和孔体积较大,其对AKD的吸附量高,而规则晶型结构的CCC的比表面积和孔体积较小,其对AKD的吸附量较低,AKD施胶效率较高。     

杨木APMP浆ASA中性施胶特性分析

以杨木碱性过氧化氢机械浆(APMP浆)和杨木漂白硫酸盐浆(BKP浆)为原料,对比考察了烯基琥珀酸酐(ASA)、填料、阳离子助剂等对杨木APMP浆和BKP浆施胶性能影响的差异。研究结果表明,ASA用量对纸张施胶度影响较大,APMP浆和BKP浆在ASA用量为0.20%时均可获得较好的施胶效果,在相同ASA用量下,APMP浆的施胶效果优于BKP浆;添加15%用量的PCC有助于改善APMP浆的ASA施胶效果,但不利于BKP浆的ASA施胶。在APMP浆中添加不同填料时,加填滑石粉与加填GCC纸张的施胶效果接近,都优于加填PCC的。APMP浆中含有较多的阴离子垃圾等,不利于ASA施胶,添加适量的阳离子助剂可显著改善APMP浆的ASA施胶效果。     

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