单一胶粘剂对涂料流变特性的影响

单一胶粘剂对涂料流变特性的影响颜进华陈克复华南理工大学制浆造纸工程国家重点实验室１前言涂料流变特性是指涂料受剪切时剪切应力、剪切速率及表观粘度的相互关系，涂料流变特性既控制着涂料的质量及其中间产品，也影响涂布加工纸的涂布工艺及其涂布纸质量。随着涂布...     

酸化膨润土对纸张涂料流变性能的影响

研究了酸化膨润土对纸张涂料流变性能的影响。结果表明,添加酸化膨润土,涂料黏度明显降低。在低剪切速率下,除了酸化膨润土用量为40份（以颜料总量100份计）的涂料表现出胀流型流体的特征外,酸化膨润土用量低于40份的涂料均表现出剪切稀化的假塑性流体特征;在高剪切速率下,纸张涂料均表现出假塑性流体的特征。纸张涂料动态频率扫描显示,涂料的黏弹性随酸化膨润土用量的增加而降低;除了酸化膨润土用量40份的纸张涂料在高频区的相位角大于45°外,其他涂料的相位角均小于45°,涂料表现出弹性大于黏性的特征。     

纸张涂料全剪切速率流变性能分析及其在涂布纸生产中的应用

对纸张涂料的全剪切速率流变性能进行了分析,并结合生产实践经验,利用全剪切速率范围内的涂料流变性能分析解决并预测涂布纸生产中出现的一些问题,为改善涂布运转性及涂布纸质量,提高纸厂经济效益提供借鉴。     

共胶粘剂地涂料流变特性的影响

本文对氧化淀粉、羧基丁苯胶乳、羧甲基纤维素（ＣＭＣ）聚乙醇（ＰＶＡ）四种胶粘剂进行交叉混合配制成的涂料进行了流变特性考研究，实验表明，在剪切速率为１０＾３Ｓ－１以下时，体系都呈剪切稀化特性，粘度与剪切速率的关系可用ηａ＝１０＾ｄＤａｌｇ６２Ｄ＋ｂｌｇＤ＋ｃ表达。含有ＣＭＣ的混合胶粘剂涂料，表观粘度最大；含有ＰＶＡ的混全胶剂涂料，表观粘度次之；含羧基丁苯胶乳比例罗大的混合胶粘剂涂料，表观粘度最小。     

流变助剂对纸张涂料粘弹性能的影响

纸张涂料具有粘弹性,主要是由于其中作为流变助剂的水溶性聚合物与其他组分的相互作用引起的.不同的流变助剂对涂料的影响程度不同.本文比较了CMC(羧甲基纤维素)、PVA(聚乙烯醇)和CMS(羧甲基淀粉)对涂料粘弹性能的影响,表明CMC比PVA和CMS更能提高体系的粘弹性能,并从组分间的相互作用方面分析了它们对粘弹性能的作用机理.     

亚麻籽胶的流变性质

研究了亚麻籽胶的静态流变性质和动态流变性质.静态流变性质的研究表明:亚麻籽胶溶液是剪切变稀的假塑性流体,其表观粘度随质量分数的增加逐渐增加;温度对亚麻籽胶溶液的表观粘度的影响符合Arrhenius模型,活化能为27.48kJ/mol;pH值对亚麻籽胶溶液的表观粘度影响很大;盐的加入导致亚麻籽胶溶液的粘度降低.动态流变性质的研究表明,亚麻籽胶溶液显示弱凝胶的特性.     

壳聚糖纺丝液流变性能改善方法初探

文章介绍了最近在改善壳聚糖纺丝液流变性能方面的研究现状。用均质处理器对壳聚糖纺丝液进行了处理。结果发现均质处理会使壳聚糖纺丝液的静态表观粘度降低,同时,在一定范围内,使得壳聚糖纺丝液的动态表观粘度有明显升高。     

涂料添加剂及其配比对涂布纸张性能影响的研究

涂料配方的选择不仅影响涂布纸的性能,还决定涂布纸的最终质量。不同助剂的配比对涂料和纸张性能的影响也不同。本文分别对涂料固含量、保水剂、生物胶乳、分散剂等造纸助剂及纳米粒子对纸张涂料流变性和纸张性能的影响进行单因素分析。在此基础上,选取固含量、分散剂含量、纳米粒子含量进行纸张平滑度的响应面分析,在固含量55%,分散剂含量1.0%,纳米粒子含量4%的最优参数下纸张平滑度值4.32s;选取保水剂含量、生物胶乳含量、纳米粒子含量对纸张表面强度进行响应面分析,在保水剂含量0.8%,生物胶乳含量18%,纳米粒子含量4%的最优参数下纸张表面强度值1.06m/s。     

纸张涂料用纳米TiO2表面改性的研究

用十六酸对纳米TiO2进行表面改性,采用FT-IR、XRD、接触角及流变学等测试方法对纳米TiO2的界面性质进行了表征.分析结果表明,改性后十六酸存纳米TiO2表面形成化学吸附,改性纳米TiO2表现出较好的亲油疏水性.在有机相中能够良好分散;将改性前后的纳米TiO2分别加入到纸张涂料体系中.制得纳米TiO2复合纸张涂料,涂料流变实验表明,含改性纳米TiO2的复合纸张涂料具有较高的动态弹性模量和黏性模量.     

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。     

无机载银抗菌沸石对涂料流变性能的影响

载银抗菌沸石具有良好的持久性、耐高温性和安全性。通过AR550流变仪研究了采用涂布方式生产载银抗菌纸时,载银抗菌沸石对典型造纸涂料流变性能的影响。研究表明:载银抗菌沸石的加入不会对造纸涂料流变性能产生负面影响,相反它对稠度系数和表观黏度有一定降低作用。对涂料流变曲线拟合研究表明,Herschel-Bulkley模型能较好地拟合涂料的流变曲线,添加载银抗菌沸石后涂料仍具有剪切稀化特性,弹性贮存模量也有一定的降低,而黏性损耗模量与损耗角δ变化不大。     

Rheological Properties and Adhesion Characteristics of Flour-Based Batters for Chicken Nuggets as affected by Three Hydrocolloids

Time-dependency, apparent viscosity, shear-thinning behavior, recovery and adhesion characteristics were determined on 30% solids flour-based batters containing hydrocolloids (guar, xanthan and carboxymethylcellulose, CMC) at 0.25, 0.5, and 1.0%. Most batters were thixotropic. Batters containing xanthan gum had the greatest apparent viscosity followed in decreasing order by guar gum, CMC and control batters. Apparent viscosity correlated highly positively with batter adhesion characteristics measured on chicken nuggets as coating pickup, overall yield, and cooked yield. Mixer viscometry techniques were useful to follow changes in rheological properties caused by mixing speed and time.     

挤压米糠流变特性的试验研究

基于流变学原理。确定了挤压米糠的表观黏度模型，并对模型进行了线性回归建模，以便进行试验拟合。试验研究了挤压米糠的流变特性，结果表明米糠的表观黏度随剪切速率的增加而减小。呈现出假塑性流体的流动行为；米糠的表观黏度随温度的升高和原料水分的增加而减小。用计算机程序试验拟合了米糠黏度的方程。     

易染色聚酯熔体的流变性能

采用高压毛细管流变仪研究了易染色超仿棉聚酯熔体的流变行为,并将其与聚酯熔体的流变行为进行了对比。结果表明：易染色聚酯熔体属于典型的假塑性非牛顿流体,表现出明显的剪切变稀特性;随着温度的升高,易染色聚酯熔体的表观黏度下降,非牛顿指数逐渐增大,结构黏度指数减小;易染色聚酯熔体的黏流活化能随着剪切速率的增大而减小,即其表观黏度的温度敏感性随着剪切速率的增大而降低;与PET熔体相比,易染色聚酯熔体的表观黏度对温度和剪切速率的依赖性更高,且结构化程度更大。     

Rheological behavior of concentrated yogurt (Labneh)

In this paper, the rheological behavior of concentrated yogurt (Labneh) is presented. The rheological behavior of Labneh was measured using a rotational viscometer in a temperature range of 5‐55°C. The tested Labneh exhibited shear‐thinning and thixotropic behaviors. The power law model expressed as τ = mγ ⁿ was found to be the most appropriate for the rheological model of Labneh. The effects of temperature on power law parameters were determined. The parameter (m) significantly decreased with increasing temperature, while the parameter (n) slightly increased with temperature. It was also found that the Weltmann's model described well the relationship between the apparent viscosity of Labneh and the shearing time. The activation energy of flow was nearly constant for all samples tested and not affected by the shear rate.     

Rheological Examination of White Pepper Slurries to Determine Prior Treatment of Pepper with Gamma-Irradiation

ABSTRACT: A study was carried out to examine rheological properties for the detection of irradiated white pepper by viscosity and maximum viscosity methods. Samples in polyethylene bags were irradiated and measured for apparent viscosity and maximum viscosity. The viscosity of all samples decreased with increasing stirring speeds and irradiation dose. This trend was similar for maximum viscosity. The results suggest that the detection of irradiated white pepper is possible by both the viscometric and maximum viscosity methods. Therefore, maximum viscosity method can be used as a new method to detect the irradiated white pepper.     

Thermal conductivity as influenced by the temperature and apparent viscosity of dairy products

This study aimed to evaluate the rheological behavior and thermal conductivity of dairy products, composed of the same chemical components but with different formulations, as a function of temperature. Subsequently, thermal conductivity was related to the apparent viscosity of yogurt, fermented dairy beverage, and fermented milk. Thermal conductivity measures and rheological tests were performed at 5, 10, 15, 20, and 25°C using linear probe heating and an oscillatory rheometer with concentric cylinder geometry, respectively. The results were compared with those calculated using the parallel, series, and Maxwell-Eucken models as a function of temperature, and the discrepancies in the results are discussed. Linear equations were fitted to evaluate the influence of temperature on the thermal conductivity of the dairy products. The rheological behavior, specifically apparent viscosity versus shear rate, was influenced by temperature. Herschel-Bulkley, power law, and Newton's law models were used to fit the experimental data. The Herschel-Bulkley model best described the adjustments for yogurt, the power law model did so for fermented dairy beverages, and Newton's law model did so for fermented milk and was then used to determine the rheological parameters. Fermented milk showed a Newtonian trend, whereas yogurt and fermented dairy beverage were shear thinning. Apparent viscosity was correlated with temperature by the Arrhenius equation. The formulation influenced the effective thermal conductivity. The relationship between the 2 properties was established by fixing the temperature and expressing conductivity as a function of apparent viscosity. Thermal conductivity increased with viscosity and decreased with increasing temperature.     

聚丙烯/改性聚酯共混体系流变行为研究

聚合物共混改性是利用现有高聚物采用性能组合方式开发新产品的重要途径之一。本论文主要利用哈克流变仪和毛细管流变仪研究聚丙烯/改性聚酯共混体系的流变行为。研究发现,改性聚酯的添加对共混体系的粘度有所影响,其影响规律与所施加的剪切力方式和大小有关。在一定的剪切力作用下,共混体系表观粘度随温度的变化符合阿累尼乌斯关系。     

浓缩石榴汁流变特性研究

研究了不同浓度的石榴汁在不同温度下的流变特性。结果表明:在实验范围内,石榴汁表现为胀塑性流体,通过回归分析,温度对表观粘度的影响可以用Arrhenius方程表示,浓度对表观粘度的影响可以用指数方程更好地表示,并推导出温度和浓度对表观粘度综合影响的方程式。该方程的建立可以用来预测实际加工过程中一定温度和浓度时石榴汁的表观粘度。     

Behaviour of Oxidized Starches Towards Cyanoethylation

Starch of different molecular sizes brought about by oxidation of maize and rice starches were cyanoethylated under identical conditions. The degree of cyanoethylation, expressed as % N, was found to depend mainly on the molecular size of starch irrespective of its kind. As the molecular size decreases the degree of cyanoethylation increases. Cyanoethyl starches are water soluble and can be precipitated by ethanol. It was also found that the rheological properties are determined by the nitrogen content of cyanoethyl starch. When the latter acquires low nitrogen content, it exhibits non-Newtonian pseudoplastic behaviour. On the other hand, cyanoethyl starches with higher nitrogen content are characterized by non-Newtonian thixotropic. At constant rate of shear, the apparent viscosity of cyanoethyl starches is directly related to its molecular size. Storing of pastes prepared from these cyanoethyl starches for 7 d exerts considerable influence on rheological properties and apparent viscosity of these derivatives.