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1.
采用羧甲基纤维素(CMC)对聚酰胺多胺环氧氯丙烷(PAE)树脂进行改性,以期在保持原有增湿强作用不变的前提下,提高PAE树脂的使用性能,并赋予其一定的增强性能,降低PAE树脂的使用成本。探讨了PAE树脂的改性工艺,并对改性PAE树脂进行傅里叶红外光谱表征,研究了改性PAE树脂对纸张的增强效果及对浆料Zeta电位、滤水性能的影响。结果表明,在PAE树脂成品中引入9%的CMC为最优改性工艺;在此工艺条件下制备的改性PAE树脂用量为0.6%时,浆料的滤水性能最优;在相同用量下(0.6%),与传统PAE树脂相比,添加改性PAE树脂所抄纸张的抗张指数提高约22%,湿抗张指数提高约19%,耐折度提高约13%,撕裂指数提高约5%,内结合强度提高约6%。  相似文献   

2.
采用羧甲基纤维素(CMC)对聚酰胺多胺环氧氯丙烷(PAE)树脂进行改性,以期在保持原有增湿强作用不变的前提下,提高PAE树脂的使用性能,并赋予其一定的增强性能,降低PAE树脂的使用成本。探讨了PAE树脂的改性工艺,并对改性PAE树脂进行傅里叶红外光谱表征,研究了改性PAE树脂对纸张的增强效果及对浆料Zeta电位、滤水性能的影响。结果表明,在PAE树脂成品中引入9%的CMC为最优改性工艺;在此工艺条件下制备的改性PAE树脂用量为0.6%时,浆料的滤水性能最优;在相同用量下(0.6%),与传统PAE树脂相比,添加改性PAE树脂所抄纸张的抗张指数提高约22%,湿抗张指数提高约19%,耐折度提高约13%,撕裂指数提高约5%,内结合强度提高约6%。  相似文献   

3.
本文研究醚化改性剂对PAE树脂的改性工艺,探讨醚化改性PAE树脂的应用性能,研究显示经醚化改性后的PAE树脂具有比传统PAE树脂更优的性能。实验结果表明:醚化剂对PAE树脂的末端改性优于过程改性,醚化剂的较佳用量为15%;在此条件下改性后的PAE树脂用量为0.5%时,与改性前相比能够进一步提高纸张干抗张指数约3%,而降低湿抗张指数约19%,耐折度提高约9%,撕裂指数提高约19%,内结合强度提高约37%。  相似文献   

4.
探讨了羟基改性剂对PAE树脂的改性方式、改性剂用量,并对改性PAE树脂的增强性能进行分析。研究表明,羟基改性剂可以对PAE树脂进行改性,改性后不仅降低了PAE树脂的生产成本,还提高了PAE树脂的增干强效果。结果显示羟基改性剂对PAE树脂的末端改性优于过程改性;此时改性剂的较佳用量为15%;改性后的PAE树脂具有高的增干强性能及低的增湿强性能;当改性后的PAE树脂用量为0.5%时,与改性前相比,能够进一步提高纸张干抗张指数约7%,而降低湿抗张指数约23%,耐折度提高约13%,撕裂指数提高约25%,内结合强度提高约42%。  相似文献   

5.
该文研究了羧甲基纤维素(CMC)对聚酰胺多胺环氧氯丙烷(PAE)树脂的改性工艺,探讨了CMC改性PAE树脂的应用性能及改性后PAE树脂的动态流变特性.研究显示,经CMC改性后的PAE树脂,具有比传统PAE树脂更优异的性能.实验结果表明:CMC对PAE树脂的末端改性优于过程改性;CMC的较佳用量为9%(以改性PAE树脂质量计);在此情况下,当改性PAE树脂用量为0.3%(以绝干浆质量计)时,与未改性的PAE树脂相比,纸张干抗张指数提高约8%,湿抗张指数降低约5%,耐折度提高约21%,撕裂指数提高约25%,内结合强度提高约48%.  相似文献   

6.
通过对海藻酸钠(SA)荧光标记,使用荧光显微镜、Zeta电位仪、扫描电镜(SEM)和原子力显微镜(AFM)等研究聚酰胺多胺环氧氯丙烷(PAE)/SA二元增湿强体系在纸张表面的分布、纤维的结合方式及其作用机理。结果表明:SA被荧光标记后,发现PAE-SA均匀分散地分布在纸张纤维的表面;加入0.75%PAE和0.50%(相对于绝干浆)SA,浆料电位下降不明显,纸张湿强度高;PAE/SA在纸张表面形成膜包覆;PAE/SA纸张纤维能吸附更多的细小组分。  相似文献   

7.
研究了阳离子聚合电解质聚酰胺环氧氯丙烷(PAE)和阴离子聚合电解质海藻酸钠(SA)所组成的二元纸张增强系统对漂白针叶木化学浆性能的影响。重点研究了先加入PAE再加入SA(PAE/SA)对纸张性能的影响,并与单独使用PAE或SA进行了比较。结果表明,采用PAE/SA二元纸张增强系统后,纤维间结合力提高,纸张的抗张强度、耐折度、耐破度和湿强度显著增强,但撕裂强度降低,纸张紧度没有明显变化。同时发现PAE/SAZ.元增强系统对不同打浆度的纸浆均有增强效果,但打浆度不同,增强幅度亦不同。  相似文献   

8.
刘欣  吴玉英  田春华 《中华纸业》2012,33(14):15-19
研究对以合成的聚阴离子苯乙烯-丙烯酸丁酯-α-甲基丙烯酸(APSBM)乳液作为纸张湿强剂的应用条件进行了探讨。结果表明:将APSBM与阳离子型聚苯乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯(CPSBG)乳液复配使用,在达到相当的湿强效果时,耐折度和撕裂指数均有较大程度提高。将聚酰胺聚胺表环氧氯丙烷树脂(PAE)与APSBM复配使用,结果表明:添加0.7%PAE和0.3%APSBM时,纸页湿强度和耐折度都达到最大,分别为38%和398次,比单独添加1%PAE分别提高了50%和54.3%;当纸料pH=5.4时,增湿强效果最佳,湿强度可达46.7%。纸张的SEM图表明,添加PAE和APSBM可以在纸页表面形成交联网络覆盖膜,从而提高纸张的湿强度。  相似文献   

9.
该文探讨了羟基改性剂聚乙烯醇(PVA)对聚酰胺多胺环氧氯丙烷树脂(PAE树脂)的改性方式、改性剂用量,并对改性PAE树脂进行表征,研究了改性PAE树脂的应用效果.实验结果显示,PVA对PAE树脂的末端改性优于过程改性,末端改性时PVA的最优用量为15%(以改性PAE树脂总固含量计);改性后的PAE树脂具有较高的干增强性能及低的湿强性能,这样便于后续湿损纸的回收利用;采用末端改性工艺,在PVA用量为15%的情况下,当改性后的PAE树脂用量为0.5%(以绝干浆质量计)时,与原纸相比,能够进一步提高纸张干抗张指数约25%,湿强度增加约为11%,耐折度提高约136%,撕裂指数提高约44%,内结合强度提高约137%.  相似文献   

10.
通过乳液型双酚A环氧树脂(BAE)对聚乙烯亚胺(PEI)进行改性,制备出了具有强阳离子性和反应活性的改性PEI纸张增强剂。讨论了增强剂组成、添加量和助留剂添加量等因素对纸张强度的影响,并用SEM对纸样微观结构进行了表征。结果表明,BAE树脂的引入可增加聚乙烯亚胺分子与纸纤维的结合强度,改性PEI可使纸张湿强度从14.46%提高到21.65%,环压指数提高42%;sEM分析表明,纸张断裂是由纤维断裂引起的。为改性PEI可增加纤维间的结合强度提供了依据。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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。  相似文献   

15.
Microbiology of food taints   总被引:2,自引:0,他引:2  
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.  相似文献   

16.
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  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
《造纸信息》2014,(8):75-75
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.  相似文献   

20.
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  相似文献   

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