制备条件对聚酰胺蜡触流变剂性能的影响

研究了聚酰胺蜡粉末的粒径和活化试剂的种类对聚酰胺蜡触流变剂改善涂料流变性能的影响。在环氧树脂体系中,与未研磨的聚酰胺蜡相比较,研磨后的聚酰胺蜡使体系具有更好的流变性能。考察了活化剂正丁醇、异丙醇、乙醇和甲醇的加入对聚酰胺蜡流变性能的影响,发现将乙醇与异丙醇按质量比5∶7复配后活化的聚酰胺蜡浆,能使环氧树脂体系具有更高低剪切黏度和更低高剪切黏度的触流变性能。     

Studies on Wool Wax I: General Rheological Behaviour

Woll waxes were studied for their general rheological behaviour as a function of breed of animal and geographical locality. The rheological parameters studied included flow curve, structural viscosity at low as well as at high levels of shear, yield value, and plastic viscosity. The influence of temperature on these parameters was also considered.     

茂金属聚乙烯蜡对PE共混体系流变行为的影响

用毛细管流变仪研究了茂金属聚乙烯蜡改性聚乙烯共混体系的流变行为，探讨了茂金属聚乙烯蜡用量对共混体系熔体流变行为、熔体黏度、非牛顿指数和流动活化能的影响。结果表明：茂金属聚乙烯蜡对LLDPE／LDPE流动黏度降低明显，增加用量可使黏度逐渐降低；而对MPE／LLDPE／LDPE共混体系流动行为的影响比较复杂，在低剪切应力下黏度随茂金属聚乙烯蜡用量增加而逐渐降低，而在高剪切应力下黏度先增后减；茂金属聚乙烯蜡与MPE／LLDPE／LPDPE的相容性好于LLDPE／LDPE共混体系。     

Diffusion and Release of Chloramphenicol from Wool Wax in Relation to its Rheological Properties and in Presence of Surfactants

The diffusion and release of chloramphenicol from wool wax containing different proportions of hard paraffin was investigated. It was found that increasing the hard paraffin concentration in the base results in a corresponding decrease in both diffusion and release rates of the drug. The obtained results were correlated to certain rheological parameters measured for these bases. The effect of cetrimide on the diffusion and release of chloramphenicol from wool wax was also studied. It was depicted that cetrimide whether present in the matrix or in the diffusion or release media, increases markedly the rates of diffusion and release of chloramphenicol. The effect of cetrimide is proportional to its concentration.     

Effect of Wool Waxes and Wool Wax Derivatives on the Release of Some Antibiotics from a Hydrocarbon Base

The rate of diffusion of chloramphenicol and tetracycline-HCl from white petrolatum was found to increase in the presence of either wool waxes or wool wax derivatives; the effect being more pronounced in conjunction with the latter group. For both antibiotics, the releasing properties were found to keep increasing with increasing wax (local Merino) concentration; however, for each antibiotic the increase follows a special pattern. The rate of liberation of the antibiotics the increase follows a special pattern. The rate of liberation of the antibiotics could not be correlated to any investigated individual physico-chemical property of the waxes or wax derivatives.     

Physical Properties of Aqueous Solutions of Pectin Containing Sunflower Wax

The aim of this study is to investigate the physical properties of aqueous solutions of pectin (PA) containing sunflower wax (SFW), which are used as a basis for producing edible films. The stability and the rheological and microstructural characteristics of SFW/PA mixtures were evaluated. SFW/PA mixtures formed oil-in-water emulsions that were milky and opaque in appearance and were stable towards phase separation. Polarized micrographs revealed the presence of wax crystals, whose size decreased as pectin concentration increased. The rheological behavior of the aqueous solutions of pectin containing different amounts of SFW were best described by the generalized power law model of Herschel–Bulkley (H–B), which gave the best fit in all the range of shear rate values. Apparent viscosities and yield stress were determined using this model, and both properties increased with increasing pectin content. The apparent viscosity values were between 0.0095 and 0.1031 Pa s. SFW addition resulted in a small decrease in viscosity for emulsions formulated with 1 and 2 % PA, but the opposite effect was observed for emulsions formulated with 3 % PA. In addition, shear stress values were higher for emulsions with higher PA content, but were not affected by SFW addition.     

三种添加剂对复合植物蜡性能的影响

以聚乙烯蜡、软质微晶蜡和硬质微晶蜡为稳定剂,用量为0%~20%,添加到复合植物蜡中,测定其基本物理性能(针入度、滴点、运动粘度)的变化。实验结果表明,3种稳定剂加入量在0%~20%范围内:聚乙烯蜡对复合植物蜡的运动粘度和针入度的影响相对较小,变化比较平缓,当添加量为20%时,滴点增加了5℃;软质微晶蜡对复合植物蜡的运动粘度、针入度的影响较大,当添加量为20%时,运动粘度整体下降2.7mm2/s、针入度降了2.7 mm;硬质微晶蜡对复合植物蜡的运动粘度影响较小,而针入度、滴点的变化幅度较大,当添加量为20%时,针入度减小了3.2 mm,滴点提高了16℃,硬质微晶蜡能很大程度的提升复合植物蜡的硬度和滴点。     

新型100％粉体聚酰胺蜡流变剂在高厚膜型防腐涂料中的应用

通过实例详细介绍了新型100％粉体聚酰胺蜡流变剂的特点。以溶剂型高厚膜型环氧及聚氨酯防腐涂料体系为例,从不同角度,如活化温度、分散性、Stormer黏度、Brookfield黏度、抗流挂性、热贮存稳定性、抗结粒性等方面来阐述其与传统型流变剂的区别。     

Effect of Beeswax on the Rheological Characteristics of Soft Paraffin

The effect of beeswax on the rheological characteristics of soft paraffin was investigated. The rheological parameters considered were the flow pattern, structural viscosity, yield value, plastic viscosity, coefficients B and M of thixotropic breakdown and structural recovery. Evidence is presented to show that beeswax affects markedly the rheological characteristics of soft paraffin.     

Structure and Physical Properties of Plant Wax Crystal Networks and Their Relationship to Oil Binding Capacity

The microstructure, melting and crystallization behavior, rheological properties and oil binding capacity of crystalline networks of plant-derived waxes in edible oil were studied and then compared amongst different wax types. The critical concentrations for oleogelation of canola oil by rice bran wax (RBX), sunflower wax, candelilla wax, and carnauba wax were 1, 1, 2, and 4 %, respectively, suggesting RBX and sunflower wax are more efficient structurants. A phenomenological two-phase exponential decay model was implemented to quantify the oil-binding capacity of these oleogels. Parameters obtained from this empirical model were then evaluated against microscale structural attributes such as crystal size, mass distribution and porosity to determine the structural dependence of oil-binding capacity. Gels containing candelilla wax exhibited the greatest oil-binding capacity, as they retained nearly 90 % of their oil. This is due to the small crystal size as well as the spatial distribution of these crystals. Using a microscopic to macroscopic approach, this study examines how the structural characteristics unique to each wax and resulting oleogel system affect functionality and macroscopic behavior.     

新型微晶蜡在轮胎胎侧胶中的应用

研究新型微晶蜡在轮胎胎侧胶中的应用,并与几种国内外产品进行对比.结果表明:在胎侧胶中加入微晶蜡,胶料的门尼粘度减小,t90延长,硫化胶的耐屈挠、耐热老化、耐臭氧和耐天候老化性能提高;与其他微晶蜡相比,新型微晶蜡具有更优的耐臭氧和耐天候老化性能,在保证防护效果的同时改善了胶料的外观.     

Influence of Powder Agglomerates on the Structure and Rheological Behavior of Injection-Molded Zirconia–Wax Suspensions

Surface-modified zirconia powders with 20% to 100% of the particle surface area covered with stearic acid was blended with 50 vol% of an organic wax vehicle for rheological study. These fractions of surface coverage gave rise to different degrees of powder agglomeration. A further adsorption of the wax on partially modified particle surfaces was examined, which was likely to exhibit different degrees of solid surface-wax affinity depending upon whether the particle surfaces were "bare" or "premodified." The rheological behavior of the suspensions revealed that the shear viscosity as well as the yield stress increased appreciably with decreased fractions (or surface coverage) of the pre-adsorption. The observed suspension rheology due to incomplete surface modification can be accounted for by the formation of agglomerates which suppress suspension flowability to a significant extent. The formation of the agglomerates alters the suspension structure by reduction of the maximum solid concentration (φ_max) that is attainable for a given powder. This change in suspension structure (decrease in φ_max) leads to a restriction of particle mobility, reflected as a linear function of the yield stress of the suspensions.     

水溶性高分子化合物对乳化蜡稳定性影响的研究

以水溶性高分子物质作为添加剂,与不同配方的阴离子型、阳离子型,非离子型乳化剂进行复配,考察高分子物质作为添加剂对乳化蜡性状及稳定性影响。结果表明：添加水溶性高分子后,非月E型复配乳化剂制备的乳液粘度变大,稳定性增强;随着高分子化合物疏水性增强,阴离子型乳化剂制备的乳化蜡越稳定;高分子化合物与阳离子型乳化剂的电性差异越大则相互作用越强。     

The Chemical and Physical Structure of Peat Bitumens

Peat bitumen obtained by solvent extraction of Irish high moor peat was subjected to chemical, structural and rheological characterisation. The bitumen was fractionated on the basis of solubility in n-heptane, toluene and ethyl acetate into wax, resin and asphaltene; each of these major constituent groups was further separated into sub-fractions by column chromatography using solvents of increasing polarity. All materials were chemically characterised by C, H, N and O content and infra-red spectroscopy. Molecular size distribution of the materials was determined by gel permeation chromatography and vapour pressure osmometry. Heats of fusion, measured using the differential scanning calorimeter, indicated that crystalline species were concentrated in the wax fraction. The rheological properties of the bitumen were investigated between 10 and 50°C, and the fractions were examined at 20°C. Following analysis as yield pseudoplastic fluids, flow behaviour was described in terms of yield stress, flow and consistency indices. The measured flow parameters were examined in the light of the structural implications of the calorimetry and the results of the chemical analysis. Carboxylic acids and esters which are found principally in the wax fraction are considered to be the dominating rheological influence in the bitumen, affecting physical behaviour through their ability to crystallise at low temperature and thus mechanically hinder flow, and through secondary bonding increasing viscosity in the liquid phase.     

铅笔板乳化蜡的研制

传统铅笔板制造工艺采用烤板法加蜡,利用铅笔板本身的余热,石蜡被熔化并渗入木板中。这种方法虽然简便,但铅笔板中石蜡分布不均,铅笔仍会发生活芯或膨胀变形等问题。采用石蜡、C5石油树脂以及氧化蜡等为原料,制备铅笔板乳化蜡,并对其性能进行了研究。实验确定了铅笔板用乳化蜡微乳液的配方,考察了乳化条件对制备微乳液的影响。研究结果表明:当石蜡、C5石油树脂、氧化蜡的质量比为1∶0.6∶0.4,乳化时间为30min,乳化温度为90～95℃,搅拌速度为1100r/min时可制得性能稳定的铅笔板专用防护蜡乳液。     

胶凝含蜡原油的连续剪切实验研究

胶凝含蜡原油由于其蜡晶的三维网状空间结构,具有复杂的流变性。胶凝原油的流变性质一直是研究的重点和热点。很多学者对胶凝原油的性质做了详细而又深入的研究,但这些研究一般集中在恒定剪切速率上,对胶凝原油的连续剪切的研究较少。通过控制不同的降温速率和胶凝温度,来研究胶凝原油连续剪切的变化规律。实验结果表明,当降温速率越大时,初始的粘度越小,但剪切一段时间后,不同降温速率下的粘度无多大差别;当胶凝温度越低是,其初始的结构强度越大,并且在结构破坏以后,在同一剪切速率下,其粘度也越大,但不同温度下的差距在减小;当从高到低的剪切情况下,其粘度随着剪切速率的减小,呈增大的趋势,并且这趋势越来越明显,相对于从低到高的剪切情况下,在同一剪切速率下,从低到高情况下的粘度比从高到低的粘度要大。     

原油管道内蜡沉积速率预测及分析

分别运用灰色预测理论和灰色神经网络理论对原油管道内的蜡沉积速率进行了预测分析;应用灰色人工神经网络理论,考虑剪切应力、温度梯度、粘度以及浓度梯度4个影响因素作为主要因素的对原油管道内的蜡沉积速率进行的预测,与传统的灰色预测方法相比,所得到的预测值更为接近实际值,蜡沉积速率的相对误差绝对值在1．6％以内,灰色神经网络用于管道内蜡沉积速率预测的效果良好,能为原油管道蜡沉积规律的深入研究和制定合理的清蜡周期提供理论依据。     

蜡沉积物对现场管道运行影响研究

蜡沉积是流动保障关键问题之一,前人主要研究了温度、流速等因素对沉积物厚度的影响,而关于蜡沉积物进入原油后,对管道运行影响研究报道较少。通过现场测试储罐内原油和管输原油物性,研究了储罐蜡沉积物和管道蜡沉积物进入原油后,对管道运行的影响。研究表明:加热输送含有蜡沉积物的原油,导致原油凝点显著升高,给管道安全运行带来潜在风险,应慎用加热输送方式;升高输油温度,使管道内较松软的蜡沉积物融化,蜡沉积物厚度减小,但由于蜡沉积物进入原油,导致原油凝点升高。     

An investigation on gas hydrate formation and slurry viscosity in the presence of wax crystals

Clarifying the interaction effect between hydrate and wax is of great significance to guarantee operation safety in deep water petroleum fields. Experiments in a high‐pressure hydrate slurry rheological measurement system were carried out to investigate hydrate formation and slurry viscosity in the presence of wax crystals. Results indicate that the presence of wax crystals can prolong hydrate nucleation induction time, and its influence on hydrate growth depends on multiple factors. Higher stirring rate can obviously promote hydrate growth rate, while its influence on hydrate nucleation induction time is complicated. Higher initial pressure will promote hydrate formation. Gas hydrate slurry shows a shear‐thinning behavior, and slurry viscosity increases with the increase of wax content and initial pressure. A semiempirical viscosity model showing a well‐fitting is established for hydrate slurry with wax crystals by considering the aggregation and breakage of hydrate particles, wax crystals, and water droplets. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3502–3518, 2018