聚丙烯酰胺改善硫酸钙加填纸张PG黄染料染色效率的研究

针对纸厂生产实践中无水硫酸钙(CaSO_4)加入抄造体系后会严重影响PG黄染料染色效率的问题,本课题提出一种在浆料中加入聚丙烯酰胺进行改善的方法。探究了阳离子聚丙烯酰胺(CPAM)和两性聚丙烯酰胺(AmPAM)两种高聚物对PG黄染料染色效率的影响,其中CPAM或者AmPAM的加入均能有效提高PG黄染料的染色效率。研究表明,当CPAM添加量为0.05%或AmPAM添加量为0.06%时,PG黄染料的染色效果提高较为明显,且这两种助剂的加入均能提高填料CaSO_4的留着率。并进一步推断了2种聚丙烯酰胺对改善PG黄染料在纸张中的染色效率及无水CaSO_4填料留着率的影响机制。     

传统抄纸工艺与细小纤维预絮聚抄造工艺的对比研究

以杨木P-RC APMP为原料,对其进行筛分,研究了传统抄造工艺与共絮聚工艺下浆料悬浮液的Zeta电位、白水的阳离子需求量、细小组分的留着率以及成纸的性能。结果表明:与传统抄造工艺相比较,共絮聚工艺能提高细小纤维和填料的留着,分别提高了5.98%和6.28%;纸张的白度、不透明度和强度性能均有提高,但纸张的松厚度有所减小。传统抄造工艺下浆料的Zeta电位绝对值和白水阳离子需求量都要比共絮聚工艺条件下的高。     

纳米微晶纤维素与CPAM、CS的协同增强与助留助滤作用

研究了纳米微晶纤维素(NCC)作为增强剂和助留剂在纸业的应用。结果表明:(1)单独添加NCC对抗张强度、撕裂强度和耐破度都有一定的增强效果。(2)阳离子淀粉(CS)/NCC二元增强体系对增强纸张物理强度的效果比单独添加CS的增强效果好,且CS和NCC不同的添加方式对纸张物理强度有不同的影响。(3)单独添加NCC对纸料和填料有一定的留着效果,但并不十分明显。(4)阳离子聚丙烯酰胺(CPAM)或阳离子淀粉(CS)与NCC组成二元助留体系,对纸料和填料的留着具有协同作用,均比单独添加CPAM或CS的留着效果好。     

使用双重助留增强剂的效果

目前,国内助剂正由单一品种添加发展到采用两种或两种以上助剂的添加技术,使不同的助剂特性协同发挥作用,从而提高应用效果,现将我厂对BS双重助留增强剂的试用情况介绍于后:1 作用机理 BS双重助留增强剂助剂Ⅰ为低分子量阳离子聚电解质,助剂Ⅱ为高分子量阴离子聚电解质。当把助剂Ⅰ加入到浆料以后,阳离子聚合物分子吸附在填料和纤维表面上,通过电性作用形成微絮凝体,再加入助剂Ⅱ后,阳离子强烈地吸附阴离子聚合物,通过架桥连接使纸浆中的纤维素、填料接枝共聚,形成了粘着力强、抗剪切力的絮凝体系,从而大大提高了细小纤维和填料的留着,同时提高了纸张的物理强度。     

聚合氯化铝改性硅灰石提高填料留着率研究

研究了在硅灰石填料悬浮液中添加聚合氯化铝(PAC)对填料Zeta电位和留着率的影响。结果表明,当PAC用量为5%(相对于硅灰石)时,硅灰石填料的Zeta电位接近于0,此时硅灰石在纸张中的留着率最高;但在同时使用阳离子聚丙烯酰胺（CPAM）作为助留剂的情况下,硅灰石填料的Zeta电位接近于0时的PAC用量下的留着效果并不是最好,而是当PAC用量为1.0%~1.5%时,硅灰石在纸张中的留着效果好,并且PAC改性后的硅灰石在高得率浆中的填料留着率提高幅度比在化学浆中的大。     

造纸助剂的预混合工艺对纸张性能的影响

基于减少直接加入各种化学品繁琐的操作过程和因加填导致的纸张强度和填料留着等指标的下降,本实验通过提前预混合各种造纸化学品,然后直接用于抄纸,来改善纸张的强度和填料留着等性质。实验中将填料PCC、AKD、阳离子淀粉、CPAM、CP-3在抄纸前迅速地混合,然后加入浆料中,进行抄纸。研究结果表明:预混合合适的添加顺序为:PCC悬浮液→AKD乳液→阳离子淀粉→CPAM。各种化学品的添加量,实验中固定了AKD的用量为绝干浆的0.25%。根据实验的纸张性能检测的结果,PCC较合适用量为纸张总质量的20%,阳离子淀粉用量为绝干浆的1.5%,CPAM、CP-3的用量要根据留着和其他的纸张性质来决定。     

不同助留体系对装饰原纸二氧化钛复合填料留着效果的影响

本研究分别分析了单元助留体系阳离子聚酰胺环氧氯丙烷树脂（PAE）,双元助留体系PAE/阴离子聚丙烯酰胺（APAM）、PAE/膨润土（MMT）、PAE/阳离子聚丙烯酰胺（CPAM）,三元助留体系PAE/CPAM/APAM、PAE/CPAM/MMT对装饰原纸TiO₂/滑石粉复合填料留着效果的影响。确定了各个体系的最佳添加量,并筛选出助留效果最好的助留体系。结果表明,当PAE添加量2.0%、CPAM添加量0.08%、MMT添加量0.6%时,组成的PAE/CPAM/MMT三元助留体系留着效果最佳,此时,浆料和填料留着率分别为89.5%和65.0%,纸张的不透明度、白度及匀度分别为98.5%、86.6%和91。     

交联型聚丙烯酰胺的制备与应用研究

为提高新闻纸印刷适性,满足高速印刷需求,本文以丙烯酰胺、阳离子单体甲基丙烯酸二甲氨基乙酯和内烯酰氧乙基三甲基氯化铵、阴离子单体衣康酸、活性单体羟甲基丙烯酰胺、交联单体三烯丙基异三聚氰酸酯为原料,采用水溶液聚合方法,制备了中等分子量、低黏度、交联型的活性两性聚丙烯酰胺作为纸张干强剂,并对其红外、电荷密度、分子量表征。根据国内浆料和造纸现状,选用了脱墨浆料和中电导抄造体系进行应用研究,应用结果表明:在白水电导1000-1200us/cm的条件下,聚丙烯酰胺的干添加量为浆料的0.8%,纸张定量为60g/m~2,制备的干强剂可给予纸张卓越的性能和纸厂可控的成本,能提高纸张拉毛速度14%,提高纸张撕裂强度20%,增强纸张内结合力30%,浆料的滤水性能提升27%,对填料的助留性能提高了10%。     

填料对纸张性能的影响

分析造纸填料的性能、特点、作用,在纸张中的存在状态及抄造条件对填料和填料留着率的影响。讨论加填对纸张性能的影响,探讨纸页抄造中如何提高填料的单程留着率。     

双助留体系下预絮聚加填对纸张性能的影响

采用阳离子聚丙烯酰胺(CPAM)、皂土双组分助留体系预絮聚烷基烯酮二聚体(AKD)和沉淀碳酸钙(PCC),探究各组分添加顺序对纸张施胶效果、填料留着率及纸张物理性能的影响。对比传统加填工艺发现,采用[PCC+CPAM+皂土+CS+AKD]的预絮聚加填工艺时,纸张的物理性能提高最为明显,纸张抗张指数提高22.4%,耐破指数提高52.0%,同时,纸张的匀度指数从111.9降低至69.0,匀度显著改善。将AKD提前加入浆料中,然后采用[PCC+CS+CPAM+皂土]的预絮聚加填工艺时,纸张的施胶度和填料留着率明显提高,相比传统纸张加填工艺,Cobb_(60)值降低了24.8%,填料留着率提高了3.7%。但所有预絮聚加填工艺由于增大了PCC的颗粒大小,使得纸张白度、不透明度、透气度都有所降低。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.