干燥方式对亚微米纤维复合空气过滤材料结构和性能的影响

以原纤化天丝和玻璃棉这2种亚微米纤维为原料,通过湿法成形的方式将其复合在无纺布基材上制得空气过滤材料（以下简称滤材）,探究了冷冻干燥及加热干燥对滤材结构和性能的影响。结果表明,冷冻干燥能较好地保留湿纸幅中亚微米纤维的形态,减少纤维收缩,对原纤化天丝的影响尤为显著;当原纤化天丝与玻璃棉的配比分别为2∶8、4∶6、6∶4、8∶2时,冷冻干燥滤材的过滤效率分别比加热干燥滤材的过滤效率高3.5%、5.5%、9.8%和12.2%,过滤阻力分别比加热干燥滤材低20.4%、28.1%、23.3%和33.2%。可见冷冻干燥可显著提高亚微米纤维复合空气过滤材料的过滤效率,降低其过滤阻力。     

天丝纤维在变压器绝缘纸板中的应用

天丝纤维是一种溶剂型再生纤维素纤维,研究了天丝纤维原纤化程度及其对浆料性能的影响,探讨了天丝纤维与针叶木浆配抄对变压器绝缘纸板机械性能和电气性能的影响。研究结果表明,天丝纤维容易原纤化,原纤化程度越高,纤维变得更加柔软和扭曲,表面更加粗糙,分丝帚化越多;相对100%针叶木浆抄造的绝缘纸板,针叶木浆与天丝纤维配比为85∶15配抄的绝缘纸板的紧度降低4.8%,抗张指数下降2.9%,吸油率提高11.9%,在空气中的击穿电压提高5.8%,在油中的击穿电压提高25.8%,天丝纤维显著提高了绝缘纸板的吸油率和电气强度。     

漂白硫酸盐竹浆与阔叶木浆PFI磨浆特性的对比研究

本研究主要利用PFI磨浆机对漂白硫酸盐竹浆与阔叶木浆的磨浆特性及其成纸性能进行对比研究。研究发现相同磨浆转数下,竹浆打浆度略高于阔叶木浆,湿重比阔叶木浆高;磨浆前期（打浆度低于35．5°SR）,相同打浆度下,竹浆纤维成纸的抗张指数低于阔叶木浆,而后随着打浆度的增加,竹浆纤维成纸的抗张指数高于阔叶木浆。相同打浆度下,竹浆...     

桉木PFI磨浆过程中纤维形态的变化

用扫描电镜和多媒体纤维镜观察桉木浆PFI磨浆过程中纤维的变化。观察发现:桉木浆磨浆前期,纤维开始分丝帚化,纤维次生壁S1层的微纤维逐渐剥离下来,纤维被严重切断;磨浆中期,纤维次生壁S2层的微纤维逐渐剥离下来,纤维以分丝帚化为主,同时被切断;磨浆后期,纤维次生壁S3层的微纤维缓慢地剥离下来,纤维分丝帚化和切断的速度缓慢。     

磨浆pH控制对装饰原纸遮盖性能的影响

通过进行不同组别的单一变量对照实验来研究不同p H下打浆对装饰原纸遮盖性能与原纸和浸胶压板亮度的影响。实验结果表明：在不影响装饰原纸成纸p H的前提下，在比较高的p H条件下进行磨浆处理的漂白阔叶木浆纤维分丝帚化度与扭结度都较好，与成品钛白粉等无机物填料的结合度上升。综合来看有利于钛白粉等填料在纤维上的附着。     

打浆工艺对造纸法再造烟叶基片松厚度的影响

采用PFI磨对烟草浆进行打浆,分别研究了磨浆转数、磨齿间隙和打浆浓度对造纸法再造烟叶基片松厚度的影响,同时通过对不同打浆参数条件下得到的烟草浆纤维形态的对比,探讨了打浆工艺对造纸法再造烟叶基片松厚度的影响。结果表明,烟草浆打浆过程中,随着磨浆转数的减少,磨齿间隙的增加以及打浆浓度的提高,纤维数量下降、平均长度上升、粗度增加,与木浆、轻质碳酸钙混合抄造出的基片松厚度提高;在本实验打浆工艺范围内,磨浆转数和磨齿间隙对烟草浆纤维形态以及抄造出的基片松厚度的影响大于打浆浓度的影响;由于烟草浆纤维本身的特点,不同的打浆工艺对其帚化效果影响很小;适宜的PFI磨打浆工艺为:磨浆转数10000~15000转,磨齿间隙0~0.5 mm,打浆浓度10.0%~11.7%。     

原纤化Tencel纤维对滤纸性能的影响

对Tencel纤维随打浆强度的变化进行了研究;对比了相同质量分数下,高原纤化Tencel纤维和玻璃棉分别与木浆纤维复配抄纸的成纸的物理性能和过滤性能.结果表明,随着打浆强度的提高,Tencel纤维的形态会发生显著改变,最终出现大量原纤;Tencel纤维和玻璃棉纤维分别与木浆复配后,所得纸样的透气度和孔径接近,但玻璃棉复配纸样的多通过滤性能较优,而高原纤化Tencel纤维复配纸样则有明显的强度优势.     

MFC负载铁离子催化对纸浆纤维的芬顿表面氧化作用研究

将富含铁离子的微纤化纤维素（MFC-铁离子）吸附于漂白硫酸盐针叶木浆纤维表面,然后对纸浆纤维表面进行芬顿氧化;通过激光扫描共聚焦显微镜（LSCM）间接检测纤维上芬顿反应产生的羟基自由基（·OH）,使用扫描电子显微镜（SEM）和能谱仪（EDS）检测纤维上铁元素的分布;评价了在相同打浆转数下,芬顿表面氧化处理对纤维素平均聚合度（DP）、纤维形态及成纸抗张指数和撕裂指数的影响。结果表明,芬顿表面氧化预处理产生的·OH主要分布在纸浆纤维表面,并且基本保留了纤维平均长度;与原浆相比,芬顿表面氧化浆的纤维素平均DP仅下降约4.9%,打浆转数8000转时,成纸抗张指数和撕裂指数较原浆成纸分别提高了20.9%和25.7%。     

机械制浆工艺的原理

在低定量含机械浆印刷纸中，有3个不同的性能需要同时达到最佳化，它们是影响不透明度的光散射系数、影响强度的纤维长度和对成纸适印性产生作用的紧度。对某树种而言，不论是磨石磨木浆、盘磨浆还是硫酸盐浆，其纤维的光散射系数和纤维长度之间具有某种独特的联系。降低磨浆强度或提高化学处理程度或温度时，能减少纤维切断，提高长纤维含量。     

慈竹浆与桉木浆PFI磨浆过程中纤维形态的对比研究

用PFI磨对漂白硫酸盐慈竹浆与桉木浆进行磨浆,利用多媒体显微镜和扫描电子显微镜(SEM)观察慈竹浆和桉木浆纤维在打浆过程中纤维形态的变化。结果发现:打浆前期,慈竹浆纤维和桉木浆纤维的初生壁(P)和次生壁外层(S1)破除,分丝帚化情况大致相同;打浆中期,随着S2层微纤维的剥离,慈竹浆纤维露出S3层,分丝帚化减少;桉木浆纤维S2层微纤维持续剥离,分丝帚化增加。打浆后期,慈竹浆纤维的S3层不容易剥离出微纤维,分丝帚化不明显;桉木浆纤维S3层容易剥离出微纤维,分丝帚化明显。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status