高性能液晶聚酯纤维的成型与结构

以国外资料为主，综述了热致液晶聚酯的熔体纺丝工艺及纤维的结构与性能，给出了含有Ｖｅｃｔｒａ复合纤维的热处理条件与力学性能。     

基于对羟基苯丙酸的生物基液晶共聚酯纤维的合成与性能

针对常规生物基纤维力学性能与耐热性不足的问题,以6-羟基-2-萘甲酸、对羟基苯甲酸和对羟基苯丙酸(HPPA)为原料,采用一锅熔融聚合法合成了生物基液晶共聚酯,并通过熔融纺丝制备得到初生纤维,对共聚酯及其初生纤维的结构与性能进行研究.结果表明:制备得到的生物基液晶共聚酯为向列型液晶,其熔点在200℃左右,并随着HPPA添...     

芳香族聚酯液晶Vectran纤维的性能与应用

芳香族聚酯液晶Vectran纤维是一种新型的高性能纤维。分析了Vectran热致液晶聚芳酯纤维的结构特征、力学性能、热性能、耐化学性能、抗蠕变及耐摩擦性能,详述了影响纤维力学性能的因素,介绍了该纤维的应用领域。     

区域热处理制备高模高强的等规聚丙烯纤维

引言制备高模、高强纤维或薄膜的研究工作早已在进行,并对超分子结构和力学性质之间的关系给予极大的兴趣。其工艺有:超拉伸、高压挤出、液晶(或流动聚合物溶液)纺丝、胶体纺丝和热拉伸等。许多作者也提出了称之为“区域热处理”的新方法,这种方法迄今已应用于聚酯、锦纶6和聚乙烯中,并发现对改善这些聚合物     

爱柯诺尔(ェュノ一ル)纤维

爱柯诺尔纤维系日本住友化学工业公司于去年十月新上市的高强度、高弹性模量纤维。它是用含(?)结构.单元组成的超耐热性全芳香族聚酯,即热塑性、热致性高分子液晶经液晶纺丝而制得。据该     

芳香族共聚酯的改性

前言自从PET在四十年代被发现以来,聚酯一直被人们当作重点研究着,因而聚酯的合成方法及其品种层出不穷。七十年代中期,芳香族共聚酯作为一种新型材料被合成出来了。芳香族共聚酯具有热致性液晶的特性,在熔融时呈现出光学各向异性,通过熔融纺丝可以获得高强度(20～30克/旦)、高模量(400～600克/旦)纤维,这是继Kevlar纤维之后的又一种高强、高模纤维。无论芳香     

热处理对热致液晶聚芳酯纤维结构与性能的影响

针对热致液晶聚芳酯(TLCPAR)初生纤维结构不稳定、强度不高的问题,对其进行热处理以提高纤维分子质量,进而提高纤维的强度。将处于松弛状态的TLCPAR纤维置于热处理箱中,在不同的热处理温度和时间下进行热处理。借助广角X射线衍射仪、纱线强伸度仪测试与分析纤维的结晶度、晶粒尺寸、晶区取向以及纤维力学性能的变化。结果表明:热处理后TLCPAR纤维的(110)晶面和(211)晶面的晶粒尺寸显著增加,230 ℃热处理48 h后纤维的结晶度增加了37.1%,取向度仅下降2%,说明TLCPAR纤维中大分子链的堆砌更有序、更紧密;热处理后结构变化使TLCPAR纤维断裂强度增加了86.8%,弹性模量增加了20.9%。     

全芳香族热致液晶共聚酯相转变的研究

本文用DSC、TOT、WAXD等方法对合成的全芳族热致液晶共聚酯的液晶相行为进行了研究,结果表明:共聚酯具有向列型热致液晶性、低熔点和宽液晶相等特点。     

文摘天地

０１１２４３　生丝纤度指标与样本大小的相关性分析／蔡福敏,杜爱娟／丝绸检验,２００１,Ｎｏ．ｌ,８～１５ 对１５０９批不同规格、不同产地、不同缫制方式的生丝,在不同回数和不同绞数情况下检测平均纤度、纤度偏差及纤度最大偏差三项指标,并进行对比分析,得到其三项指标与样本单位大小、样本数量之间的相关联系。０１１２４４　热处理对共聚酯复合纤维性能的影响／仲蕾兰等／中国纺织大学学报,２０００,Ｎｏ,６,１０９～１１３ 着重讨论了热处理对共聚酯复合纤维性能的影响,同时还对它的超分子结构和纤维形态进行了探讨。结…     

芳香族共聚酯相变过程研究

合成了由不同配比ABA、TPA、HQ、RD组成的全芳香族共聚酯。采用搅拌乳光法、热台偏光显微镜观察、DSC以及升温过程中的WAXD的测定,可以断定它们都是向列型热致性液晶共聚酯。测定了它们的Tm和Ti。实验结果表明提高HQ的含量,共聚酯的三维有序性增加、熔点提高、液晶温度范围增加。通过对X—射线衍射图的分析,发现全芳香共聚酯液晶微区尺寸随温度升高而变小。鉴定热致性液晶聚合物最常用的四种方法各有千秋。必须联合使用才能获得可靠的结果。     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.     

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%.