滑石颜料高剪切流变性能的研究

使用毛细管高剪切黏度仪研究了滑石颜料分散体系的高剪切黏度性能,以及pH值、固含量、不同分散剂和润湿剂、不同粒径分布对滑石分散体系高剪切黏度的影响。同时还研究了滑石与GCC及高岭土混合浆料的高剪切黏度性能。结果表明,滑石含量越高、粒度越细,其分散浆料的高剪切黏度值越大。同时发现,滑石高剪切黏度受分散剂和润湿剂的影响不大。提高pH值有利于降低滑石分散体系的高剪切黏度。滑石与GCC混合浆料的高剪切黏度随着GCC粒度的变细而降低。当滑石与GCC的体系中加入高岭土后,混合浆料的高剪切黏度大幅增大,且随着GCC粒度的变细而增大。     

颜料悬浮液高剪切流变性的研究

采用毛细管黏度计研究了颜料悬浮液高剪切流变性的影响因素。结果表明,碱和分散剂的用量超过最佳用量能明显提高低剪切黏度,但并没有恶化高剪切流变性能。pH值变化对高剪切黏度影响不明显;提高分散剂用量能有效改善颜料悬浮液的高剪切流变性。相同固含量下,粗重钙(<2gm,66%)的高剪切流变性明显好于细重钙(<2μm,95%～96%),而高光重钙(<2gm,99%)最优。浆状重钙经过静置后,尽管低剪切黏度明显上升,但高剪切流变性能基本保持不变。     

高固含量高岭土分散体系特性的研究

采用Minitab软件中的田口设计实验方法,研究了高固含量高岭土所构成分散体系的特性,分析了分散速度、分散剂和NaOH用量对分散性能的影响,同时研究了高固含量高岭土分散体系的回黏现象。研究结果表明,分散剂用量是影响高岭土分散效果的主要因素;当固含量74%、分散剂用量0.05%、NaOH用量0.01%、转速2500 r/min、分散时间15 min时,高岭土分散体系黏度最低,分散效果最佳。     

载银沸石在鞋材抗菌整理中的应用

采用不同的分散时间、不同的分散剂用量和pH值,对载银沸石抗菌剂的分散性进行了较系统的探讨,利用Zeta电位、黏度、沉降法以及扫描电子显微镜对分散情况进行表征.同时,对分散体系进行了应用实验和抗菌检测.结果表明,分散时间、分散剂用量和pH值都是影响载银沸石分散效果的重要因素;经整理后的抗菌鞋里对大肠杆菌和金黄色葡萄球菌的杀菌率均达100%.     

分散剂对颜料分散液流变特性的影响

分散剂是加工纸涂料调制必不可少的成分。本文采用六偏磷酸钠和聚丙烯酸钠作为分散剂，分别对瓷土和碳酸钙分散液进行了分散剂用量和分散液流变性的研究。随着分散剂用量加大，分散液粘度降低，并最终达到最佳分散状态。处于最佳分散状态的白色颜料分散液是一种假塑性流体，分散液粘度和剪切速率及分散液固含量三者关系可用函数式表达。     

分散剂对白料流变特性的影响

分散剂是加工纸涂料调制必不可少的成份。本文采用六偏磷酸钠和聚丙烯酸钠作为分散剂，分别对白料（瓷土和轻钙）分散液进行了分散剂用量和分散液流变性的研究。随着分散剂用量加大，分散液粘度降低并最终达到最佳分散状态。处于最佳分散状态的白料是一种假塑性流体，分散液粘度和剪切速率及分散液固含量三者关系可用函数式表达。     

分散剂对白料流变特性的影响

分散剂是加工纸涂料调制必不可少的成份。本文采用六偏磷酸钠和聚丙烯酸钠作为分散剂，分别对白料（瓷土和轻钙）分散液进行了分散剂用量和液流变性的研究。随着分散剂用量加大，分散液粘度降低并最终达到最佳分散状态。处于最佳分散状态的白料是一种假塑性流体，分散液粘度和剪切速率及分散液固含量三才关系可用函数式表达。     

高岭土最佳分散条件的确定与探讨

分析了茂名山阁高岭土的最佳分散条件,研究了聚丙烯酸钠(DC)和六偏磷酸钠(SHMP)分散剂对高岭土泥浆黏度的影响.结果表明,分散茂名山阁高岭土,DC和SHMP的最佳用量分别为0.48%和0.50%,这两种体系的黏浓度分别为69.7%和69.4%;DC和SHMP单独使用的降黏效果比复合使用的降黏效果更明显;使用DC的高岭士泥浆,pH值调节剂(NaOH)的最佳用量为0.05%,使用SHMP的高岭土泥浆,NaOH的最佳用量为0.06%.     

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.     

纳米ATO在制备抗静电PET单体EG中的分散性

 以乙二醇(EG)为分散介质,研究分散方法、分散剂种类、分散剂浓度、分散液pH值和球磨时间等工艺条件对纳米锑掺杂二氧化锡(ATO)在EG中分散性的影响。用TEM和分散液的吸光度对各工艺条件下的分散情况进行表征。研究结果表明:采用球磨分散方法,选择硅烷偶联剂KH570为分散剂,分散剂对ATO的质量分数为1.5%,分散液pH值为8.5,球磨时间为36 h的工艺条件,ATO在EG中的分散效果最佳,为制备分散性能优良的纳米复合抗静电纤维提供了前提条件。     

颜料悬浮液固含量对低剪切黏度的影响

分析了不同种类颜料悬浮液固含量对低剪切黏度的影响。结果表明,尽管颜料悬浮液固含量与黏度平方根倒数的线性关系相当好,但对于相当一部分颜料,由此得到的黏浓度数据偏差仍然不可接受;而且根据测算,在黏浓度点附近,固含量的微小波动会造成低剪切黏度很大的变化,导致黏浓度的测定结果不可靠。在给定固含量条件下测定黏度,控制黏度在较低范围可以获得很好的测定精度。     

高效分散剂的合成及在重质碳酸钙研磨中的应用

以丙烯酸、单体M和单体N为共聚单体,过硫酸铵和亚硫酸氢钠为引发体系合成了一种高效分散剂,研究了单体摩尔比和过硫酸铵与亚硫酸氢钠质量比对其研磨碳酸钙浆料黏度的影响。结果表明,当亚硫酸氢钠与过硫酸铵的质量比在3左右,丙烯酸与单体M的摩尔比为10∶1,功能单体N加入量为单体总量的0.2%,此时共聚物相对分子质量在3 000～5 000时,其可用于研磨至98级重质碳酸钙浆料,且浆钙黏度相对较低,流动性较好。     

PSEUDOPLASTIC AND RHEOPECTIC PROPERTIES OF A GLOBULAR PROTEIN (β-LACTOGLOBULIN) SOLUTION1

The apparent viscosity of β-lactoglobulin solutions was studied as a function of shear rate using a cone and plate uiscometer (Ferranti-Shirley Viscometer System). Aqueous buffered solutions (pH 7, ionic strength 0.04) containing up to 40% protein were subjected to a rate of shear between 800 and 17,000 sec ^-1. At protein concentrations of 5% and lower, the viscosity was independent of the shear rate or the time of shearing. At protein concentrations of 10% or higher, the viscosity decreased asymptotically with an increasing shear rate. At a constant shear rate, the viscosity of 10-30%β-lactoglobulin solutions increased with shearing time. However, this rheopectic property was not consistently observed but, rather, was dependent on the rate of shear at concentrations lower than 20%. A rheopectic hysteresis effect was observed for 10-30% protein solutions whereas thixotropy was observed for 40% solutions. The rheopectic nature appeared to be the result of the permanent denaturation of protein characterized by UV absorption and gel filtration.     

Heat and pH stability of alkali-extractable corn arabinoxylan and its xylanase-hydrolyzate and their viscosity behavior

Abstract: In in vitro batch fermentations, both alkali‐extractable corn arabinoxylan (CAX) and its xylanase‐hydrolyzate (CH) were utilized by human fecal microbiota and produced similar short chain fatty acid (SCFA) contents and desirable long fermentation profiles with low initial gas production. Fortification of these arabinoxylans into processed foods would contribute desirable dietary fiber benefits to humans. Heat and pH stability, as well as viscosity behavior of CAX and CH were investigated. Size exclusion chromatography was used to analyze the molecular size distribution after treatment at different pH's and heating temperatures for different time periods. Treated under boiling and pressure cooking conditions at pH 3, CAX was degraded to a smaller molecular size, whereas the molecular size of the CH showed only a minor decrease. CAX and CH were mostly stable at neutral pH, except when CAX was treated under pressure for 60 min that slightly lowered molecular size. At 37 °C, neither CAX nor CH was adversely affected by treatment at low or neutral pH. The viscosities of solutions containing 5% and 10% of CAX were 48.7 and 637.0 mPa.s, respectively that were higher than those of solutions containing 5% and 10% of its hydrolyzate at shear rate 1 s^?1. The CAX solutions showed Newtonian flow behavior, whereas shear‐thinning behavior was observed in CH solutions. In conclusion, the hydrolyzate of CAX has potential to be used in high fiber drinks due to its favorable fermentation properties, higher pH and heat stability, lower and shear‐thinning viscosity, and lighter color than the native CAX. Practical Application: Arabinoxylan extracted by an alkali from corn bran is a soluble fiber with a desirable low initial and extended fermentation property. Corn arabinoxylan hydrolyzate using an endoxylanase was much more stable at different levels of acidity and heat than the native arabinoxylan, and showed lower solution viscosity and shear‐thinning property that indicates its potential as an alternative functional dietary fiber for the beverage industry.     

Relating rheological measurements to primary and secondary skin feeling when mineral‐based and Fischer–Tropsch wax‐based cosmetic emulsions and jellies are applied to the skin

Rheology measurements were correlated to skin sensations occurring when cream and petroleum jelly cosmetic products containing different amounts of synthetic Fischer–Tropsch wax were applied to the skin. A panel of 15 people with a background in cosmetic product development were asked to rate skin feelings when a range of petroleum jelly and cream samples are applied to the skin. Primary skin feel, or the spreadability of a cosmetic product, was correlated to the product's flow onset and maximum viscosity as measured by a Anton Paar rheometer, whereas secondary skin feel or the sensation occurring at the end of application when the product was completely rubbed into the skin was correlated to the product's viscosity measured at high shear rates. The cream samples prepared with a petroleum jelly containing 10% and 20% Fischer–Tropsch wax fell within the boundary of good primary skin feeling of cream products. Predominantly, synthetic petroleum jellies were given the best assessments in terms of primary skin feeling and were used with mineral‐based petroleum jellies to determine the boundary of good primary skin feeling for petroleum jelly products. The further away a product falls from this rheological boundary the poorer the skin feeling assessment appears to be by the panel. Products containing Fischer–Tropsch waxes were given the best assessment by the panel for secondary skin feeling. Comments from the panel include that these products feel silky and light on the skin. The higher the Fischer–Tropsch wax content, the lower viscosity was at high shear rate (? = 500 s^?1) and the higher the assessment by the panel. Rheological measurements can be used to objectively determine skin sensation when products are applied to the skin; this may shorten research and development times. A rheology boundary of certain product viscosity and shear stress applied is associated with good primary skin feeling for lotions, creams and petroleum jellies. Lower product viscosity at high shear rate seems to be associated with better secondary skin feeling. Products with higher Fischer–Tropsch wax content appear to be rated higher in terms of secondary skin feeling.     

底物浓度对碱性蛋白酶水解面筋流变特性的影响

本文较系统地研究了Alcalase碱性蛋白酶催化不同浓度小麦面筋蛋白水解过程中酶解产物的表观现象、表观粘度、剪切应力和流变特性。研究结果表明:酶解体系中小麦面筋的浓度越高,p H值下降幅度越少,在反应刚开始的6 h内是p H值变化最明显的区间,固形物浓度越高的样品,越早进入变化平稳的阶段。随着固形物浓度的提升和酶解时间的延长,酶解液的水分活度有下降的趋势,且固形物浓度越大,水分活度下降幅度越大,下降速度越快。在整个反应过程中,各固形物浓度酶解物的表观粘度和剪切应力均会随着酶解时间的延长而不断下降;固形物浓度越大下降趋势越明显,且不同固形物浓度酶解液的表观粘度和剪切应力的大小始终保持40%32%24%16%8%。此外,研究发现Ostwald-dewaele模型可以很好的拟合碱性蛋白酶催化不同固形物浓度小麦面筋蛋白酶解液的流变特性。     

Rheological properties of spinning dopes and spun fibres produced from plasma - alginate mixtures

The tensile and shear strengths of fibres produced by extruding dopes of 2.0% sodium alginate and 6.0% blood plasma into a coagulating bath of calcium chloride (5% w/v) at pH 4.0, varied according to the guluronic acid block content and molecular weight (viscosity) of the alginates. The shear resistance of the fibres was not dependent on guluronic acid block content or alginate viscosity. However, when calculated per gram of dry matter, fibres containing alginates of high guluronic acid block contents had significantly greater resistance to shear than fibres spun from alginates of low guluronic acid block content although there was still no significant dependence on alginate viscosity or degree of polymerization.
The tensile strength of fibres produced from high guluronic acid block alginates was not related to the viscosity of the sample. However, in fibres containing low guluronic acid block contents the strength increased as the degree of polymerization increased. These relationships were equally valid whether calculated on a wet or dry basis. In addition there was an inverse correlation between percentage elongation at maximum tensile stress and the viscosity of the spinning dopes.
Possible explanations for these observations are discussed.     

无机填充剂对聚酰胺湿法涂层商标织物性能的影响

针对聚酰胺湿法涂层商标织物存在的抗黏结性和吸墨性不佳、pH值偏高等问题,着重研究各类无机填充剂应用于涂层浆中的稳定性、流变性、涂层膜表面形貌、拉伸性能以及涂层织物风格、吸墨性、白度、pH值和耐水洗色牢度性能等,分析其对湿法涂层商标织物性能的影响。结果表明:含碳酸钙和高岭土的涂层浆稳定性较高,其中含碳酸钙的涂层膜断裂伸长率为30.22%,柔韧性较佳,但其涂层织物的pH值为8.25;而含水滑石的涂层浆稳定性和分散性相对较差,且制得的涂层织物的pH值为8.55;含硅灰石的涂层浆流变性优异,涂层膜表面均匀光滑,且具有大量微孔结构,吸墨性更好,涂层织物白度高,耐水洗色牢度达4~5级,pH值为7.32,符合环保要求。     

Extraction and Functional Properties of Barley β-Glucan as Affected by Temperature and pH

Barley is high in β-glucan, a soluble fiber component. Effects of extraction temperature (40 55 C) and pH (7.0 10.0) on recovery, purity and functional properties of β-glucan were investigated on whole Condor barley flour. At pH 7.0, 8.0 and 55°C, 86.5% of the β-glucan in the feed flour was recovered in the gum product with 89.1% (d.w.b.) purity. β-Glucan content increased (p < 0.05) with temperature but not with pH. Apparent viscosity of 1% (w/v) dispersions of β-glucan gum from pH 7.0 increased (p < 0.05) with extraction temperature at constant shear rate and viscosity decreased slightly with increasing shear rate. Whippability and foam stability of gums from pH 8.0 and 45°C were maximum. Emulsions prepared with β-glucan gum from pH 7.0 and 55@c were 63% stable after centrifugation. Barley β-glucan shows great potential as a thickener or stabilizer.