纤维素在离子液体中的均相接枝共聚

以离子液体为反应介质,过硫酸铵为引发剂,研究了纤维素与丙烯酸在离子液体中的均相接枝共聚,通过正交实验与单因素实验考察了单体用量、引发剂用呈、反应温度和反应时间对接枝效果的影响.实验结果表明.接枝反应的最佳条件为:单体与纤维素质量比为4:1,引发剂与纤维素质量比为1:10,反应温度60℃,反应时间2 h,在此条件下.接枝率可达96.7%.通过红外光谱进一步表明了接枝共聚物的生成.     

离子液体中自由基反应制备纤维素接枝共聚物

通过季胺化反应合成离子型液体1-丁基,3-甲基氯化咪唑[Bmin]Cl,13C NMR结果表明有效地合成了目标产物。将脱脂棉纤维素溶解于合成的离子液体中,研究讨论了[Bmin]Cl对其溶解性能及溶解前后纤维素的变化。基于自由基聚合反应的原理,使纤维素在[Bmin]Cl中均相与丙烯酰胺接枝共聚,FT-IR证明了接枝产物的生成,凯氏定氮法测量计算得接枝率达60%。正交试验结果表明各因素对接枝率的影响的主次顺序为:引发剂与纤维素的质量比>反应时间>单体与纤维素的质量比>反应温度。     

魔芋葡甘聚糖-丙烯腈接枝共聚反应动力学研究

以硝酸铈铵作为引发剂,丙烯腈为单体,对魔芋葡甘聚糖与丙烯腈接枝共聚反应动力学进行了研究.通过考察接枝反应速率与引发剂浓度、单体浓度、魔芋葡甘聚糖浓度及反应温度的关系,得到各影响因子对接枝共聚反应速率的反应级数,由此关联推导出该实验条件下接枝反应速率表达式,其反应过程的表观活化能为22.08kJ/mol.     

基于改性纤维素的图书保护膜的制备与研究

本实验以LiCl/DMAc体系为反应介质,过硫酸铵为引发剂,进行了纤维素与甲基丙烯酸甲酯的均相接枝共聚,通过重量法研究了均相条件下改性纤维素的最佳制备条件。通过考察影响接枝效果的各种因素,确定最佳的接枝条件为:反应时间2h,单体与纤维素的质量比为1:1,引发剂与纤维素质量比为6:50,反应温度为80℃。FTIR和SEM结果证实了接枝反应的发生。利用相转化法将在最佳接枝条件下制备的改性纤维素铸涂成膜,成功制备了基于改性纤维素的图书保护膜。结果表明,所制备的图书保护膜具有很好的机械性能和很高的应用推广价值。     

超声辅助碱预处理秸秆的接枝改性

以秸秆作为原材料,采用超声辅助氢氧化钠预处理的方法,利用丙烯酸和丙烯酰胺作为单体,通过接枝反应制备改性木质纤维素材料。实验过程中研究了超声时间、碱液预处理时间、接枝反应温度、引发剂用量、交联剂用量5个因素对改性秸秆接枝产率的影响,最后使用扫描电镜(SEM)及红外光谱(FTIR)验证了秸秆表面发生了接枝反应。实验结果表明,预处理程度越大,秸秆接枝产率越高,接枝反应的最佳反应条件为:反应温度70℃,引发剂用量0.9 g,交联剂用量1g。     

丙烯腈与涤纶的接枝共聚反应及产物性能的研究

研究了丙烯腈与涤纶纤维的接枝共聚反应。从实验结果得出了聚合反应速率与引发剂浓度、单体浓度、纤维用量及反应温度的关系,并由此求出反应的表观速率方程和表观活化能。还对接枝纤维的性能进行了研究。     

聚酯纤维光接枝丙烯酸聚合反应动力学研究

为了改善聚酯纤维的服用性能,必须对其进行改性。实验分析了聚酯纤维接枝丙烯酸体系聚合温度、引发剂浓度、单体浓度与初始接枝聚合速率的依赖关系。结果表明:光敏剂浓度与接枝率呈1.08次方关系,与单体浓度呈1.37次方关系。基于聚酯纤维光接枝聚合的终止反应主要是自由基单基终止反应的假设提出相应的接枝聚合机制,并建立了聚合速率模型,与聚合温度服从Arrhenius关系,得出了聚酯纤维接枝丙烯酸聚合反应表观活化能为29.33 kJ/mol。     

针叶木纤维化学改性及产物吸附性

通过接枝共聚反应在纤维素分子上引入强配位性功能基,可以实现对水中Ca2+、Mg2+等金属离子的络合吸附,达到循环冷却水系统防垢的目的。本文主要研究以硝酸铈铵为引发剂,以马来酸酐为单体,对针叶木纤维进行接枝共聚改性的反应规律,探讨了反应温度、反应时间、单体用量、引发剂用量等因素对纤维素接枝率的影响,确定了最佳的改性工艺条件。并对改性产物的吸附性进行了研究。     

不同纤维素原料上接枝合成ATRP大分子用引发剂的研究

原子转移自由基聚合(ATRP)备受瞩目,因使用该方法合成聚合物具有可控性。将该方法用于纤维素接枝共聚,就可能在纤维素上接枝功能性聚合物。在此类方法中能够决定ATRP反应成败的重要因素之一就是ATRP引发剂制备。本文以纳米纤维素(CNC)、微晶纤维素(MCC)、漂白桉木浆、未漂桉木浆为原料,以4-二甲氨基吡啶(DMAP)为催化剂,三乙胺(TEA)和四氢呋喃(THF)为溶剂在近乎无水的条件下与2-溴异丁酰溴酰化制备了可用于ATRP反应的重要的大分子引发剂。并通过红外、XPS等比较其接枝状况,为纤维素进行ATRP接枝聚合提供理论基础。     

淀粉/MMA-EA自交联型接枝共聚物的合成与结构表征

在联联剂存在下,以硝酸铵为引发剂研究了玉米淀粉与甲基丙烯酸甲酯和丙烯酸乙酯进行自交联接枝共聚合成反应的规律,讨论了引发剂浓度、单体浓度、反应温度和反应时间对接枝共聚反应的影响。实验结果表明,在引发剂浓度为７．０＊１０＾－３ｍｏｌ／ｌ、单体浓度为１．３０ｍｏｌ／ｌ、反应温度为５１℃、反应时间为２．５小时,自交联接枝共聚物的接枝率较高。通过红外光谱和Ｘ－射线粉末衍射对共聚物进行了结构表征。     

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