纤维素纳米纤维接枝聚水凝胶的制备及其结构性能的研究

将聚N-异丙基丙烯酰胺(PNIPAM)接枝到纤维素纳米纤维上,通过增大凝胶比表面积、缩小体积尺寸提高温度响应速度。PNIPAM接枝的最佳反应条件为:反应温度40℃、纤维素纳米纤维膜和N-异丙基丙烯酰胺质量比m(N)∶m(C)=15.5∶1、引发剂浓度10.5 mmol/L、反应时间3 h。扫描电子显微镜表明,纤维表面经NIPAM接枝处理后,纤维间出现粘结现象且表面粗糙。红外光谱和X射线光电子能谱表明,PNIPAM成功接枝在纤维素纤维上。差热扫描表明,PNIPAM-g-Cell接枝率为30%时,水凝胶的LCST显著提高。去溶胀动力学表明,接枝率越高,PNIPAM-g-Cell水凝胶越敏感;PNIPAM-g-Cel扩散信号强度比值越大,扩散程度越大。     

PNIPAAM类材料接枝方法的研究现状

聚N-异丙基丙烯酰胺(PNIPAAM)是现今研究最多、发展最快的一种新型热敏性聚合物,但其较差的机械强度限制了它的应用效果。为克服这一不足,将PNIPAAM接枝于其它力学性能较好的高分子基材上是一种可行的方法,同时也可在一定程度上赋予高分子基材某些特殊的性能。综述了近年来有关聚N-异丙基丙烯酰胺的主要接枝聚合方法,如射线辐射接枝、溶液自由基接枝、光引发接枝、低温等离子体接枝等以及其国内外的研究现状。     

氨基硅油整理法在温敏纺织品制备中的应用

温敏纺织品作为智能纺织品的重要组成部分,可响应环境温度的变化而调节自身的性能,在调温调湿、抗浸储水、生物医用等领域具有良好的应用前景。然而,如何将温敏聚合物高效温和地接枝到纺织品上是温敏纺织品制备过程中的难题。介绍了一种简单易行、普适性强的接枝方法,采用氨基硅油整理法在织物表面引入高活性的反应基团氨基,再通过原子转移自由基聚合(ATRP)技术接枝温敏高分子链。经由氨基硅油整理的棉织物柔顺性提高,水洗稳定性良好,红外和接触角等实验结果均证明温敏性单体N-异丙基丙烯酰胺(NIPAAm)被成功接枝聚合到织物表面,且接枝率高达41.2%。所得织物具有良好的温敏性能,可通过改变温度实现织物表面亲/疏水性的可逆转变。     

H2O2-H2A引发的PNIPAAm接枝棉纤维的制备与功能性研究

以双氧水-抗坏血酸(H₂O₂-H₂A)为引发剂，水为溶剂，通过溶液自由基接枝聚合反应引发棉纤维接枝聚N-异丙基丙烯酰胺(PNIPAAm)。红外分析表明，PNIPAAm已成功接枝到棉纤维上。研究单体浓度固定时引发剂浓度对棉纤维接枝率的影响，测量不同温度下水滴在接枝棉表面的瞬时接触角，结果表明在最低临界溶液温度(LCST)左右接枝棉具有温敏亲/疏水性。在不同温度下对接枝棉进行滴水试验，即将水滴加到接枝棉上观察其完全吸收的时间，不同温度下的浸润时间差值越大，接枝棉温敏吸水性越强，当引发剂溶度为0.06 mol/L时，接枝棉的温敏吸水性最强。     

聚丙烯非织造布的氨基化改性及对铬的吸附

对聚丙烯(PP)非织造布进行表面接枝聚多巴胺(PDA),然后以N,N-二甲基丙烯酰胺为交联剂、过硫酸铵为引发剂,将多氨基超支化聚合物(HBP)接枝到PP-PDA表面,以提高对重金属的吸附性能。当反应温度为50℃时,PP的聚多巴胺接枝率最高;当过硫酸铵质量分数为1.5%、N,N-二甲基丙烯酰胺质量分数为0.25%、HBP质量分数为10%、反应温度70℃、反应时间4 h时,PP-PDA非织造布上的HBP接枝率最高,对重金属Cr6+的吸附性能最好。     

纤维素改性多功能缓蚀阻垢剂的研制

以羧甲基纤维素为基材,选取丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、马来酸酐(MA)为原料,采用氧化还原体系的过硫酸铵-尿素作引发剂,通过水溶液聚合的方法,制得含有酸酐基团和磺酸基团的羧甲基纤维素接枝聚合物(CMCg-AM-MA-AMPS)。     

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。     

丙烯酸接枝淀粉浆料的研究概况

总结目前丙烯酸类接枝淀粉浆料的研究现状和发展趋势。阐述了丙烯酸类单体与天然淀粉接枝共聚的聚合方法、引发剂等,并分别介绍了丙烯酸(盐)、丙烯酸酯、丙烯酰胺、丙烯腈等四种类型的单体与淀粉接枝共聚的产物作为浆料的上浆性能。指出:将合成聚合物的性能引入到天然淀粉中,可提高淀粉的上浆性能。认为:丙烯酸(盐)、丙烯酸酯、丙烯酰胺接枝淀粉都可用于涤棉纱的上浆。     

酰胺型长链氨烃基改性硅油的合成及表征

以N-(3-二甲氨基丙基)甲基丙烯酰胺为单体,聚甲基氢硅氧烷为聚合物,在氯铂酸-异丙醇催化剂作用下进行硅氢加成反应,合成氨基改性有机硅柔软剂,并对合成物的结构进行IR表征分析。结果表明:N-(3-二甲氨基丙基)甲基丙烯酰胺单体的硅氢加成反应得到了预期设想的合成物,将具有独特性能的氨基基团通过硅氢加成反应接枝到聚甲基氢硅氧烷的侧链上,获得加成产物。     

温敏感应蚕丝织物的制备及性能研究

为制备透气透湿智能调节功能的温敏响应蚕丝织物,以N-异丙基丙烯酰胺（NIPAM）和聚（乙二醇）甲基丙烯酸酯（EGMA）为单体,采用无皂乳液聚合法合成聚N-异丙基丙烯酰胺（PNIPAM）及聚[N-异丙基丙烯酰胺-co-聚（乙二醇）甲基丙烯酸酯][P(NIPAM-co-EGMA)]温敏微凝胶,通过浸轧法将所合成的温敏聚合物整理到蚕丝织物上,并进行测试表征。结果表明：合成的PNIPAM具有良好的温敏特性,其最低临界溶液温度（LCST）为33℃,整理后织物表现出随温度变化的透气透湿性调节能力;并且随着温度在LCST上下的转变,整理后织物表现出亲水和疏水的变换;但整理后织物手感较差,当加入EGMA共聚后得到的P(NIPAM-co-EGMA),整理后织物手感明显改善,同时整理后织物的温湿度调节能力提高。     

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