改性纳米CaCO3分散体系稳定性和扩展DLVO理论

通过对分散体系黏度、固含量及Zeta电位的测定,探讨了表面改性过程的超声预处理、反应温度、改性剂用量及体系pH值等因素对改性纳米CaCO3水相分散体系稳定性的影响.结果表明,对纳米CaCO3水相分散体系进行超声预处理15min,以铝锆有机金属络合物偶联剂为改性剂,其质量分数为2.5%,同时控制改性体系的pH值为9时,改性纳米CaCO3水相分散体系的黏度较小,固含量较大,分散稳定性较佳.利用扩展DLVO理论对分散体系的稳定机理进行探讨,认为改性纳米CaCO3水相分散稳定性的改善主要归因于偶联剂在纳米颗粒表面的吸附使得空间位阻效应变大,从而空间位阻势能增大.     

改性纳米CaCO3水相分散体系流变行为及其流变参数拟合(Ⅱ)——固含量和pH值对分散体系流变行为的影响

采用铝锆偶联剂对纳米CaCO3进行表面改性,着重探讨体系固含墩和pH值对改性纳米CaCO3水相分散体系流变行为的影响,并借助非牛顿流体模型实现流变参数的拟合.结果表明,随着改性纳米CaCO3水相分散体系固含量的增加,分散体系的流动性相对变筹.当改性纳米CaCO3分散体系同含量为10%时,拟合分析得到分散体系的屈服应力和零剪切黏度分别为1.254 Pa和0.1043 Pa·s;增加分散体系固含量至40%时,分散体系的屈服应力和零剪切黏度增大至7.563 Pa和146.0 Pa·8.当改性纳米CaCO3分散体系固含量为10%时,对于pH值为7的分散体系,拟合分析得到的屈服应力为1.879 Pa,而pH值为9的分散体系的屈服应力为1.250 Pa,这说明适宜的体系pH值有利于提高分散体系的稳定性和流动性.     

改性纳米CaCO3水相分散体系流变行为及其流变参数拟合(Ⅰ)——铝锆偶联剂用量对分散体系流变行为的影响

采用铝锆偶联剂对纳米CaCO,进行表面改性,对改性纳米CaCO3水相分散体系的流变数据进行测定,并借助非牛顿流体模型实现流变参数的拟合.结果表明,在低剪切速率下,改性纳米CaCO3水相分散体系的表观黏度随着剪切速率的增大而下降,即剪切变稀,呈现假塑性流体特性;在高剪切速率下,随着剪切速率的增大,分散体系的表观黏度变化很小.呈现近牛顿型流体特性.采用铝锆偶联剂对纳米CaCO3,进行表面改性,可明显改善纳米CaCO3在水相体系中的流动性,使屈服应力、零剪切黏度及极限黏度都明显减小.根据Herschel-Bulkley模型拟合结果,未经表面改性的纳米CaCO3水相分散体系的流动特性指数和屈服应力分别为1.489和2.767 Pa,呈现剪切变稠流动趋势,表明分散体系的不稳定性,部分粒子发牛团聚;而经2.0%铝锆偶联剂改性的纳米CaCO3水相分散体系的流动特性指数和屈服应力分别为0.880和1.250 Pa,呈现明显的假塑性流体特性,分散体系流动性较好.     

纳米CaCO3用于颜料化表面施胶的研究

通过与淀粉、淀粉+GCC两种施胶液进行对比,探讨了纳米CaCO3在纸张表面施胶中的应用效果。结果表明,分散好的纳米CaCO3通过表面施胶在纸张表面形成的膜连续性好,纸张表面很平整。与未经表面施胶的原纸相比,使用含纳米CaCO3的施胶液表面施胶后纸张的施胶度略有提高,平滑度上升的幅度达到56.1%,抗张强度提高了12.0%,表面强度和油墨吸收性都得到了显著的改善,白度和不透明度有所下降。     

纳米CaCO3的表面改性及在水中的分散性能

利用阳离子表面活性剂十六烷基三甲基溴化铵改性纳米CaCO3.对改性前后的纳米CaC03进行了FT-IR光谱分析和透射电镜观察,测定了沉降体积、表观黏度、浊度和颗粒粒度分布,对其在水中的分散性能进行了评价.结果表明,经表面改性后,纳米CaCO3在水中的润湿性及分散稳定性有很大改善.     

纳米复合染整助剂

对纳米复合染整助剂的制备条件、技术、检测方法及应用方法进行了综述.认为使用特殊的表面活性剂或其它化合物将无机物纳米粒子分散于水中是制备纳米复合染整助剂的关键.分散剂、电解质和pH值等对纳米粒子在液相中的分散稳定性具有明显的影响.研磨、球磨、砂磨、高速搅拌和超声波分散等手段有利于纳米粒子分散液的稳定性和应用性能的提高.此外,一些化学改性方法也可以被用来改善纳米粒子分散液的质量.扫描电镜、激光粒度分析法和紫外光谱分析等方法能够用于纳米粒子分散特性分析和检测.采用浸渍法、浸轧法和涂层法等可以把纳米复合染整助剂应用于纺织物的染整加工中.     

含有改性纳米CaCO3的纸张涂料的流变行为

以阳离子表面活性剂、偶联剂及脂肪酸为表面改性剂获得表面性能不同的3种纳米CaCO3改性产品。用透射电镜桨相关化学分析方法表征了改性纳米CaCO3的界面行为。将改性纳米CaCO3加入纸张涂料体系中,制得不同配方的纸张涂料,并对涂料的静态流动性能和动态黏弹性进行了研究。结果表明,与加入普通CaCO3的传统涂料相比,含纳米CaCO3的纸张涂料具有较高的表观黏度、动态弹性模量和黏性模量,相位角则较低。表面亲油疏水的纳米CaCO3能够很好地与胶乳、增稠剂等聚合物胶体结合,弹性模量较大;而表面亲水的纳米CaCO3所制得的纸张涂料动态黏弹性较小。     

高岭土分散液流变性的初步研究

对2种高岭土(MMO1和Premium)的流变性进行了研究,探讨了固含量、分散剂用量以及pH值对颜料分散液高剪切黏度的影响。结果表明,MMO1的最佳分散剂用量为0.15%,Premium的最佳分散剂用量为0.10%;要获得较好的高剪切特性,MMO1分散液pH值应调至8.0以上,但不应太高,Premium分散液pH值也应调至8.6左右较好。MMO1的固含量控制在68%左右较合适。而Premium固含量对高剪切黏度的影响较MMO1的明显,其分散液固含量一般控制在69%~70%。     

油墨分散体系黏度数学模型研究

油墨是由颜料粒子、连结料和助剂通过研磨混合形成的一种分散体系,表现出极其复杂的流变学性能.油墨分散体系的黏度与颜料粒子的体积浓度及其分散状态、受到的剪切作用等因素有关.本文在实验研究的基础上,通过对实验测试数据进行统计分析、整理、研究,选择适当的变量代换,利用多次分步非线性回归的数学方法,建立油墨分散体系黏度与颜料粒子体积浓度和剪切速率之间关系的数学模型,并进行了分析和检验.油墨分散体系黏度数学模型的数学性质符合典型的分散体系的流变学特征,满足Casson方程.模型黏度曲线与实验测试结果的拟合程度是理想的.     

氧化锌抗菌聚酯的制备及其性能

将纳米ZnO分散在乙二醇(EG)溶液中制成ZnO-EG分散液，然后采用原位聚合法将单体精对苯二甲酸(PTA)、EG和ZnO-EG分散液进行酯化缩聚得到抗菌改性聚酯。分析抗菌改性聚酯的聚合工艺过程，采用激光粒度分析仪对ZnO-EG分散液的粒径分布进行表征；通过偏光显微镜和DSC对抗菌改性聚酯的切片形貌和熔点进行分析，并对抗菌改性聚酯的色值、特性黏度、端羧基含量、二甘醇含量以及抗菌性能进行测定。结果表明：湿法研磨制得的纳米氧化锌分散液粒径明显小于磁力搅拌所制得，且随着湿法研磨时间的增加，分散液粒径呈现先减小后增大的趋势；当抗菌聚酯的ZnO质量分数为0.5%,特性黏度为0.687 dL/g时，纳米ZnO抗菌剂在聚酯中没有发生明显团聚而形成凝集粒子，且均匀分散在聚酯切片中；纳米ZnO抗菌剂的加入使抗菌聚酯的色值偏向光亮黄绿色，抗菌聚酯对大肠杆菌、金黄色葡萄球菌和白色念珠菌的抑菌率分别为92%、99%和78%,具有较好的抗菌性能。     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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.     

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 Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.