玉米秸秆高得率浆细小组分特性及其对纸浆性能影响

以整株玉米秸秆为原料,采用环境友好型水热预处理与磨浆处理结合,制得一种高得率浆,并对细小组分进行高压均质(60 MPa)处理,重点对细小组分含量和形态变化对抄造纸张性能的影响进行了探讨。结果表明,玉米秸秆高得率浆保水值大,浆中细小组分含量高,对纸浆强度和滤水性能有较大影响,当筛除30.7%细小组分时,纸浆的抗张强度、耐破度和环压强度均高于未筛分浆。采用高压均质处理能改变细小组分形态,向玉米秸秆高得率浆的纤维组分中添加20%高压均质处理的细小组分时,与未筛分浆相比,打浆度和未筛分浆相近,抗张指数提高30.8%、耐破指数提高59.5%、环压指数提高25.2%。     

麦草浆不同筛分组分的特性

对麦草化学浆用Baucr-McNett筛分器所分离出的各组分的化学分析表明,长纤维组分具有纤维素粘度高,结晶度指数高等特点,而多戊糖含量则长、短纤维组分相似,由此说明长纤维组分不但有较好的形态特征,而且在分子水平上也有较好的品质。长纤维组分手抄纸页的物理强度较好,富含杂细胞及细小纤维的组分强度最差;长纤维组分的白度比短纤维组分高,富含杂细胞及细小纤维的组分白度最差,从同一麦草浆分离出来的不同组分,其白度相差可高达10度。 以不同筛分组分混合配浆抄纸试验表明,纸张强度随长纤维比例增加而线性增加,富含杂细胞组分对纸张强度有不良影响。根据试验结果估计,要使麦草浆强度提高10％,必须除去20％(以麦草浆为基准)的过100目的富含杂细胞组分。 麦草化学浆含有杂细胞及细小纤维组分,这些组分在一定程度上和机械木浆的细小纤维组分相似,但麦草浆的主要性质的发展规律主要和化学木浆相似。用麦草浆所抄得的纸张松厚度随细小纤维及杂细胞组分的增加而增高,并未发现机械木浆通常存在的界限松厚度。     

不同打浆设备对二次细小纤维产生及质量的影响

利用Valley打浆机、PFI磨和HCR（高浓盘磨）对漂白硫酸盐针叶木浆料进行处理,制备、搜集二次细小纤维;观察其形态,测定黏度、比沉降容积、表面电荷等参数。结果表明：Valley细小纤维以片状组分为主,HCR细小纤维中纤丝状组分与薄片状组分含量相当,PFI细小纤维绝大部分是纤丝状组分,中高浓打浆有利于产生纤丝状细小纤维。添加细小纤维,可提高纸张紧度、平滑度、不透明度,但抗张指数、撕裂指数、耐折度则是在细小纤维加入量的某一范围内增加明显,透气度及白度降低。PFI细小纤维和HCR细小纤维较之Valley细小纤维,更能提高成纸强度及降低透气度。     

细小组分对玉米秸秆高得率浆性能和湿部化学品使用效果影响

研究了环境友好水热处理法制备的玉米秸秆高得率浆中细小组分筛除对纸浆性能和湿部化学品使用效果的影响。结果表明,玉米秸秆高得率浆中杂细胞多,细小组分含量高达62.1%,纸浆中细小组分筛除会影响纸浆脱水性能和强度性能,随着细小组分筛除率的增大,纸浆打浆度逐渐下降,各种强度指标呈先提高后降低的趋势。当细小组分筛除率为17.8%时,纸浆强度性能最佳;进一步筛除细小组分,纸浆保水值和强度性能均逐渐降低。玉米秸秆高得率浆中细小组分对施胶剂AKD、湿强剂PAE和防油剂等造纸湿部化学品使用效果的影响也较大,适量地筛除细小组分可不同程度地提高成纸的防水性、湿强度和防油性。因此,细小组分筛除是提高玉米秸秆高得率浆性能和拓宽其用途的有效途径。     

机械浆细小组分对高岭土留着的影响

实验对沉积在机械浆丝状细小纤维、片状细小纤维以及长纤维上的高岭土进行了研究,以探讨机械浆细小组分对填料留着的影响。结果表明:当浆料中加入高分子絮凝剂时,留着在浆料中不同组分上的高岭土量有显著的差异;阳离子聚丙烯酰胺(CPAM)能促进填料沉积在细小纤维上,尤其是丝状细小纤维;聚环氧乙烷(PEO)虽然只能稍微地提高高岭土的留着率,但随着其用量的增加,它能很好地分散高岭土并沉积在纤维上,这种效果对细小组分尤为显著;同时,PEO能使浆料悬浮液的细小组分释放出以纤维束或缠结纤维形式存在的细小粒子。实验还通过高岭土的留着和过滤实验比较了留着机理与过滤机理。结果表明:高岭土在滤饼上的物理吸附对它的留着有很大的影响;同样地,长纤维由于比细小纤维能更好地形成滤饼而依靠其与填料间的相互作用吸附更多的填料。     

再生纸浆与高得率浆纤维形态和强度性能的差异分析

本研究深入探讨了国产废纸浆、美废12^#和阔叶木高得率浆的纤维形态和物理强度性能。结果表明,高得率浆与国产废纸纤维形态分布近似,但纤维长度较短,细小纤维含量较高;干、湿零距抗张强度性能接近,2种纤维的强度相差不大,但与美废12^#相比存在较大差距,其中湿零距抗张指数比美废12^#低21%左右。国产废纸浆、美废12^#和高得率浆的结晶指数分别为76%、72%和68%。2种再生纸浆灰分含量高,国产废纸浆的灰分为美废12^#的3倍左右。多次回用后,2种再生纸浆纸张强度性能下降趋势较大,高得率浆纸张性能下降趋势较平缓。     

低浓磨浆对杨木BCTMP成纸性能的影响

以杨木BCTMP浆为原料,探讨低浓磨浆对化机浆纤维特性及成纸性能的影响。通过浆料筛分分析和纤维质量分析表明,随着磨浆程度的增加,浆中长纤维组分含量下降,细小纤维含量增加,纤维粗度和纤维平均长度减小,纤维卷曲、扭结程度降低,使纤维得到舒展,改善成纸性能。随着磨浆的进行,打浆度上升,成纸的松厚度下降,抗张强度及耐破度等强度性能逐步升高。当打浆度为35°SR时,重均长度和纤维粗度分别减小2.1%和5.1%,纤维卷曲和扭结指数分别降低8.0%和5.0%,利于纤维舒展;与磨浆前浆料相比,成纸松厚度下降10%,挺度、抗张指数和耐破指数分别提高20%、65.3%、23.2%,磨浆对纸张物理强度性能变化具有不同程度的影响,可以利用磨浆控制浆料中细小纤维含量来调整纸张的松厚度及强度。     

废纸浆料中纤维细小组分和无机物组分的分离技术

当今．废纸已成为纸张生产中纤维原料的最重要来源。与化学浆和机械浆相比,废纸具有诸多优点．如浆料制备的能耗更低,原料成本更加低廉。但是废纸本身也存在许多缺点,如杂质（非纤维类物质）含量较高等。其中,填料和颜料的存在已经成为影响废纸利用的主要因素。由于填料在纸张生产中的应用比例不断增加以及白水循环程度不断提高。废纸中无机物组分的含量也逐渐增加。废纸中无机物组分的增加导致在使用无机物组分含量高的废纸生产高档纸张时．经常会带来诸多的问题。例如,在使用废纸作为原料时．     

废纸浆的漂白

废纸浆料的质量和白度将决定最终纸张产品的用途,白度及质量越高,则其最终使用的范围越广。本文就废纸浆的漂白技术进行讨论。1不同种类废纸浆料的漂白废纸浆料是各种纤维的混合物,其纤维包括各种磨木浆纤维和化学浆纤维,且还含有各种填料、胶粘剂、涂料、印刷油墨载体。漂白前,原料经过脱墨、净化和筛选等工段处理后,其杂质含量大大降低,但仍是一种组分不均匀的混合物。因而在选择漂白工艺时,需要根据原料的种类,最后产品的质量要求,采用不同的处理方法。1．1木素含量较高的废纸浆料的漂白这种浆料磨木浆和未漂纤维含量较高,如…     

纤维素酶处理对麦草APMP浆性能的影响

实验采用纤维质量分析仪、扫描电镜和X射线衍射分析了纤维素酶预处理前后麦草APMP浆纤维形态及纤维素结晶度的变化.结果表明,纤维素酶的最佳处理条件为:温度60℃、酶用量6 IU/g绝干浆、pH值500～6.0;与未处理浆相比,经纤维素酶处理后麦草APMP浆的细小纤维含量下降,纤维的平均长度、扭结指数和卷曲指数增加;纤维表面变得光滑,纤维更为柔软;成纸的撕裂指数、抗张指数、耐破指数和紧度分别增加了7.6%、9.3%、15.1%和10.1%.     

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