Alleviation of the plastic deformation of gel ink under strong stress through an esterification of xanthan gum reinforcing its double helix structure

As a natural organic polymer,xanthan gum(XG)can alleviate the plastic deformation of gel ink under strong stress and realize the reasonable regulation of the rheological properties of gel ink.However,as the double-helix structure connected by hydrogen bonds cannot resist the mechanical environment of strong stress,XG shows poor shear resistance.In this study,a polymer gel with interpenetrating polymer network structure was prepared by esterifying XG,taking polystyrene maleic anhydride(SMA)as the modifier.In addition to retaining the excellent rheological properties of XG,the generated polymer gel also exhibited high shear resistance.The optimal addition amount of the esterification reaction modifier was determined as mXG:mSMA=5:3 according to the gel ink standard.With this amount,the viscosity of the modified xanthan gum(SXG)gel increased to 1578.8 mPa·s and 100.7 mPa·s at shear rates of 4 s1 and 383 s1,respectively,and the shear resistance increased more than 2 times compared to the unmodified one.It is because of the ester bond formed by esterification that the reaction strengthens the interaction between molecular segments,enabling the new gel to resist to strong mechanical stress.The new polymer gel studied in this paper and the proposed mechanism of action provide new insights for the development of high-end gel ink and also provide theoretical support for the study of rheological properties of non-Newtonian fluids.

Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

Partially hydrolyzed polyacrylamide（HPAM）as the main component of slickwater fracturing fluid is a shear-sensitive polymer,which suffers from mechanical degradation at turbulent flow rates.Five different concentrations of HPAM as well as mixtures of polyacrylamide/xanthan gum were prepared to investigate the possibility of improving shear stability of HPAM.Drag reduction（DR）measurements were performed in a closed flow loop.For HPAM solutions,the extent of DR increased from 30%to67%with increasing HPAM concentration from 100 to1000 wppm.All the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing period.Results indicated that the resistance to shear degradation increased with increasing polymer concentration.DR efficiency of 600 wppm xanthan gum（XG）was 38%,indicating that XG was not as good a drag reducer as HPAM.But with only 6%DR decline,XG solution exhibited a better shear stability compared to HPAM solutions.Mixed HPAM/XG solutions initially exhibited greater DR（40%and 55%）compared to XG,but due to shear degradation,DR%dropped for HPAM/XG solutions.Compared to 200 wppm HPAM solution,addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/XG mixed polymer solutions.

Xanthan Gum—Bio-Based Raw Material for Wood Adhesive

Due to their lower environmental impact, ease of accessibility, low cost, and biodegradability, bio-renewable sources have been used extensively in the last several decades to synthesize adhesives, substituting petrochemical-based adhesive. Vegetable oils (including palm, castor, jatropha, and soybean oils), lactic acid, potato starch, and other bio-renewable sources are all excellent sources for the synthesis of adhesives that are being taken into consideration for the synthesis of “eco-friendly” adhesives. Due to their widespread use, accessibility, affordability, and biodegradability, biobased raw materials like carbohydrates used to synthesize wood and wood composite adhesive have gradually replaced petrochemical-based adhesive. Recently, xanthan gum, a naturally occurring polymer, has drawn the interest of scientists as a potentially petroleum source replacement. It possesses specific rheological characteristics, excellent water solubility, and stability to heat, and can be used as a binder, thickener, suspending agent, and stabilizer. Xanthan gum increases the adhesive strength in addition to increasing the viscosity of water-soluble adhesives. This article discusses xanthan gum as a potential substitute for traditional raw materials derived from petroleum that is used as a raw material for adhesives.

Temperature/salt tolerance and oil recovery of xanthan gum solution enhanced by surface-modified nanosilicas

Amide-and alkyl-modified nanosilicas(AANPs)were synthesized and introduced into Xanthan gum(XG)solution,aiming to improve the temperature/salt tolerance and oil recovery.The rheological behaviors of XG/AANP hybrid dispersions were systematically studied at different concentrations,temperatures and inorganic salts.At high temperature(75C)and high salinity(10,000 mg,L1 NaCl),AANPs increase the apparent viscosity and dynamic modulus of the XG solution,and XG/AANP hybrid dispersion exhibits elastic-dominant properties.The most effective concentrations of XG and AANP interacting with each other are 1750 mg·L^(-1) and 0.74 wt%,respectively.The temperature tolerance of XG solution is not satisfactory,and high temperature further weakens the salt tolerance of XG.However,the AANPs significantly enhance the viscoelasticity the XG solution through hydrogen bonds and hydrophobic effect.Under reservoir conditions,XG/AANP hybrid recovers approximately 18.5%more OOIP(original oil in place)than AANP and 11.3%more OOIP than XG.The enhanced oil recovery mechanism of the XG/AANP hybrid is mainly increasing the sweep coefficient,the contribution from the reduction of oil-water interfacial tension is less.

Mechanical properties of dredged soil reinforced by xanthan gum and fibers

Biopolymers have become popular in geotechnical engineering as they provide a carbon-neutral alternative for soil solidification.Xanthan gum(XG)and jute fiber(JF)were selected to solidify the Yellow River dredged soil.The mechanical behavior of solidified dredged soil(SDS)was investigated using a series of uniaxial compression and splitting tension tests at different XG and JF contents and fiber lengths.The results indicate that on the 28th day,the unconfined compressive strength(UCS)values of SDS samples reached 2.83 MPa and splitting tensile strength(STS)of 0.763 MPa at an XG content of 1.5%.When the JF content was greater than 0.9%,the STS of the SDS samples decreased.This is because that the large fiber content weakened the cementation ability of XG.The addition of JF can significantly increase the strain at peak strength of SDS samples.There is a linear relationship between the UCS and STS of the dredged soils solidified by XG and JF.Microanalysis shows that the strength of SDS samples was improved mainly via the cementation of XG itself and the network structure formed by JF with soil particles.The dredged soil reinforced by XG and JF shows better mechanical performance and has great potential for application.

黄原胶(Xanthan Gum)的特性、生产及应用

黄原胶是野油菜黄单孢菌分泌于胞外的中性水溶性多糖。由于其独特的流变性质而有着极其广泛的工业应用。介绍了黄原胶的生产、特性、降解以及应用,并对其应用潜力作了预测。

黄原胶(Xanthan Gum)对小鼠免疫功能的影响

给小鼠每天分别灌胃10，2和0．4μg/g的黄原胶溶液14d，研究观察黄原胶对小鼠脾脏和胸腺、IgM－PFC反对小鼠迟发型变态反应（DTH）的影响。实验发现，黄原胶对小鼠脾脏和胸腺增重及DTH的影响未见明显变化，而使小鼠的IgM-PFC显著增加。实验结果表明，黄原胶对增加小鼠脾脏和胸腺重量及增强小鼠细胞免疫功能作用不大，而对小鼠的体液免疫功能具有明显的增强作用。

黄原胶(Xanthan gum)的主要理化性能及其抗氧化特性的初步研究

本文对国产黄原胶(本室制备)与进口黄原胶(日本生产)进行了理化性能和抗氧化作用的比较研究。两者都具有良好增稠性、触变性和耐热性能。但抗盐性和对pH的稳定性差别较大,本室黄原胶的抗盐和对pH的稳定性优于日产黄原胶,耐NaCl的浓度可达10%,而日产黄原胶添加2%以上NaCl,胶就形成胨状。本室黄原胶在pH1～14的范围内粘度变化较小,而日产黄原胶在pH4～11的范围内还比较稳定,当pH<4或>11,胶溶液即成胨状。本室黄原胶的抗氧化作用高于日产黄原胶,黄原胶添加量为0.02%,可降低油脂氧化率达10%以上。

Strength properties of xanthan gum and guar gum treated kaolin at different water contents

Nowadays,using biopolymer as a ground improvement method has become very popular.However,since biopolymers are organic and degradable,their long-term effect is not fully known.In this study,the effects of biopolymers on the mechanical behavior of kaolin clay were investigated through a comprehensive program of experiments.Two types of biopolymer,i.e.xanthan gum and guar gum were chosen to investigate the effect of biopolymer type.For this purpose,specimens were prepared using standard Proctor energy at four different water contents(25%,30%35%and 40%)with 0.5%,1%,1.5%and 2%biopolymer inclusions.The specimens were cured for 1 d,7 d,28 d and 90 d.Moreover,some of the specimens were kept in the curing room for 3 years to observe the long-term effect of the biopolymers.At the end of the curing periods,the specimens were subjected to unconfined compression test,and scanning electron microscopy(SEM)analysis was performed to observe the mechanism of strength improvement.The results revealed that the unconfined compressive strength(UCS)of the specimens treated with biopolymers increased in all biopolymer inclusion levels and water contents up to a 90-d curing period.For specimens containing xanthan gum,the maximum strength increase was observed at 25%water content and 2%xanthan gum with 90-d curing.The strength increased 5.23 times induced by xanthan gum addition when compared to the pure clay.Moreover,the increase in strength reached 8.53 times in specimens treated with guar gum.Besides,increasing water content caused more ductile behavior,thus increasing the axial deformation.

Effect of xanthan gum on the quality of low sodium salted beef and property of myofibril proteins

The effects of xanthan gum (0 % and 0.3 %) on the quality of low sodium (2.0 %, 2.4 %, 2.8 %, 3.2 %, 3.6 % and 4.0 %) salted beef and property of myofibril proteins (MP) extracted from salted beef were researched. Changes in the salting absorptivity, cooking loss, shear force, color and sensory analysis showed that xanthan gum had a positive effect on the quality of salted beef with low salinity (2.0 %, 2.4 % and 2.8 %). MP of salted beef treated with xanthan gum had higher solubility, lower hydrogen bond than that without it (P < 0.05). The decrease of surface hydrophobicity and intrinsic fluorescence intensity indicated that the chromophore of protein was brought into a hydrophobic environment in the presence of xanthan gum. The electrophoresis showed that xanthan gum could improve the concentration of myosin heavy chain, paramyosin and actin after tumble-salting. The data suggested that salted beef and its MP treated with xanthan gum and 2.8 % salt (XS3) had the best properties. Together, xanthan gum could be considered as a sodium salt substitute for the development of low sodium meat products.

Rheological and drag reduction properties of hydroxypropyl xanthan gum solutions

Hydroxypropyl xanthan gum(HXG) was prepared from xanthan gum(XG) and propylene oxide under alkaline condition. Rheological and drag reduction properties of different concentrations of aqueous HXG and XG solution were studied. The micro-structure network of HXG and XG solutions was investigated by Cryo-FESEM. The results showed that HXG and XG solutions could exhibit shear thinning property. The apparent viscosity of6 g·L-1HXG solution was 1.25 times more than that of 6 g·L-1XG solution. The storage modulus G′ and the loss modulus G″ of HXG solutions were greater than those of XG solutions, and thixotropic and viscoelastic properties were more significant in HXG solutions. The HXG and XG solutions reduced the pressure drop of straight pipe, and the maximum drag reduction of 1 g·L-1HXG and XG in smooth tube reached 72.8% and 68.1%, respectively. Drag reduction rate was increased as the concentration increased. The HXG solution may become a new polymeric drag reducer.

Synthesis and Aqueous Solution Viscosity of Hydrophobically Modified Xanthan Gum

Two xanthan gum derivatives hydrophobically modified by 4 or 8 tetradecyl chains per 100 xanthan gum structure units were synthesized. The derivatives were studied by scanning electron microscope and pyrene fluorescence spectrometry. And the aqueous solution apparent viscosity of the derivatives was investi- gated. The results indicate that the network of the derivatives with more hydrophobic groups is closer and tighter. With increasing of alkyl chain substitution degree, the hydrophobically associating interactions enhance in aqueous solution. Aqueous solution apparent viscosity of the derivatives increases with increasing of polymer concentration and alkyl substitution degree, and decreases with the increase of temperature. In the brine solution, the strong viscosity enhancement phenomenon appears. The interaction between the derivatives and surfactant sodium dodecylbenzene sulfonate is strong.

Investigation of Adsorption of Xanthan Gum on Enamel by Tapping Mode Atomic Force Microscopy

By using tapping mode atomic force microscopy(TMAFM), a polymer layer was found on the enamel surface after the exposure to xanthan gum solutions. The layer thickness is closely related to the exposure time and the concentration of xanthan gum solution. The thickness data were evaluated by a Kruskal-Wallis test and Box-Whisker Plot at a 95% confidence level(p<0.05), and a statistically significant difference among the thickness data groups was demonstrated. After the exposure to 1000, 400, 100 mg/L xanthan gum solutions, the mean of layer thickness at the adsorption equilibrium is in the ranges of 103.5_122.06, 82.4_88.94 and 45.27_55.55 nm, respectively. This phenomenon suggests that the viscosity modifying agents in the beverage might be adsorbed on the enamel surface during consumption, which may form a barrier that can protect the enamel from being attacked by acid and therefore reduce dental erosion.

An Experimental Investigation on Rheological Properties of Aqueous Xanthan Gum as a Blood Analog Fluid

Developing a shear thinning non-Newtonian fluid to substitute blood is desirable in studies of biomedicine engineering since blood is a shear thinning nonNewtonian fluid that exhibits both viscous and elastic properties, and generally not available in large volume. The rheological properties of aqueous Xanthan gum with different concentrations and temperatures were studied in present paper. The resuits show that aqueous Xanthan gum is a non-Newtonian fluid which displays remarkable shear thinning behaviour and is a suitable blood analog fluid. There is a power law distribution relationship between shear stress and shear rate, and the higher the solution concentration is, the more strongly it displays shear thinning behaviours. Viscosity values of aqueous Xanthan gum increase with the solution temperature decrease or with the solution concentration increase in linearity. Moreover at the temperature of 37℃, aqueous Xanthan gum with concentration of 0.4%e and 0.6%0 matches human blood best in rheological properties. According to the resuits, the viscosity expression varied with temperature and concentrition is obtained, and the stability of Xanthan gum solution is discussed.

Intra-articular injection of xanthan gum: A potential therapy for osteoarthritis

Osteoarthritis (OA) means inflammation of the joints, with the symptoms of joint pain, stiffness, and swelling of the joints. It is a degenerative disease that appears to be caused by both biomechanical and bio-chemical factors. Intra-articular (IA) injection treatment is one of the main treatment methods for OA because of its positive effect in reducing joint pain and increasing joint mobility. IA injection of xanthan gum (XG) could protect the joint cartilage, relieve the synovitis and reduce the OA progression in experiment OA. The injection of XG may have a long-lasting effect in the joint cavity, which could avoid frequent IA injections. However, for the development of this potential therapy, further studies such as the effective long-term pain relief properties, the detailed action mechanism and the pharmacokinetics of the XG injection will be conducted. This article briefly reviewed the preparation, safety evaluation, pharmacodynamics and possible action mechanism of XG injection, and come up with the ideas for further development of this potential therapy for OA.

Petroleum Patent Used Such Monitoring Technological Like Innovation Process of Drilling Fluids with Xanthan Gum ——World Panorama

This paper aims to discuss the importance of patenting and publishing as an instrument of incentive to technological innovation in the petroleum chemistry area. The present study has examined the publications and the patent applications published from 1974 to 2014. A technological monitoring methodology for patents in drilling fluid with xanthan gum has been compared using profiles of patent application in the world, with emphasis on Industrial Property Databases available on the internet (INPI-Br, Derwent, Espacenet, Patent Scope and USPTO) with intention to assess the main inventors, applications, applications’ countries, the IPC classification, years of application and category of claims as well as discuss the importance of patents as a means of encouraging technological innovation of xanthan gum. The United States and China stand out both in relation to the publication of papers as well as in the amount of patent filing in scientific publications with the theme drilling fluid with additive xanthan gum classified by the authors’ country of origin. It is observed that Brazil and the US lead the ranking with 15 publications (about 23.1% of the total). Among the 72 institutions obtained as a result, both Petrobras SA and Universidade Federal do Rio de Janeiro, in Brazil, lead the world ranking, with 6 publications each;in relation to the areas of knowledge, it is observed that engineering stands out in the publication of papers and the areas of chemistry, engineering, energy fuels and polymer science are noticeable in numbers of patent applications. The analysis of patent filings in the periods proposed features a significant percentage associated with the classification C09K.

野油菜黄单胞菌中gumD基因的过表达对产黄原胶的影响

目的在野油菜黄单胞菌58(Xc58)中过量表达产胶基因gumD,提高黄原胶发酵产量和质量。方法通过PCR扩增、重组质粒构建、三亲本接合等方法,将重组质粒pBBR-gumD转入原始菌Xc58。结果工程菌与原始菌相比,黄原胶产量提高11.19%,黏度提高6.31%,重均分子质量提高20.21%,乙酰基含量提高77.07%,丙酮酸含量下降6.34%。结论改造后的菌株的黄原胶发酵产量和质量都较原始菌株有所提高。

生物胶改良黏土抗崩解特性试验研究

为研究生物胶对黏土抗崩解性的影响,采用黄原胶、瓜尔胶及黄原胶与瓜尔胶质量比为1∶1混合的复合胶对黏土进行改良,通过抗崩解试验,探究生物胶的含量和种类、压实度对改良黏土抗崩解特性的影响规律,并结合扫描电镜试验进一步分析了生物胶的改良机理。结果表明:生物胶通过增强土体颗粒之间黏聚力增强改良黏土的抗崩解特性,其崩解破坏过程可分为稳定前崩解阶段、稳定崩解阶段及稳定后崩解阶段;随着生物胶含量的增大,改良黏土稳定前崩解阶段延长,崩解速率减缓,崩解率降低;复合胶改良黏土抗崩解特性在质量分数大于1.0%后强于单一生物胶;随着压实度的提升,试样抗崩解特性明显改善。

基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究

干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效提高土体的抗压强度和耐干湿循环效果。随着黄原胶含量的增加,干湿循环作用后的强度损失逐渐减小,当循环次数从0次增加到4次时,对于加入黄原胶含量分别为0%,0.5%,1.5%的试样,抗压强度分别损失了42.75%,17.2%,14.04%。(2)加固土的抗压强度与干湿循环次数之间保持指数下降的关系,当循环次数达到4次后,随着循环次数的进一步增加,抗压强度和弹性模量均在较小的变化范围内波动。(3)随着干湿循环次数的增加,黄原胶加固土的孔隙率表现出先增加后减小的趋势,连通孔隙不断扩展,而孤立孔隙表现出先增加后减小的趋势。(4)随着试样的干燥,黄原胶在土颗粒间形成网状基质,提高土体的强度和耐干湿循环能力。

黄原胶预处理对汉麻织物喷墨印花效果的影响

为解决汉麻印花织物得色量浅、清晰度差的问题,选取黄原胶为预处理剂对汉麻织物进行处理,并进行活性染料喷墨印花。结果表明:与海藻酸钠预处理剂相比,经黄原胶预处理后织物的润湿时间从32.18 s增加到98.19 s,接触角从70.13°提升至84.22°,说明预处理后黄原胶在织物表面构筑的薄膜使织物疏水性增加,进而抑制染料墨水在织物上的扩散,提升喷墨印花效果;当预处理液为1.5%黄原胶、10.0%尿素和2.0%NaHCO_(3),汽蒸时间为10 min时,织物色深达到最大值,此时,青、品红、黄和黑色色块的K/S值比海藻酸钠预处理织物分别提升了33.5%、20.2%、42.6%和109.3%,表明黄原胶预处理喷墨印花汉麻织物表现出优异的表观颜色深度;同时,印花织物的耐摩擦和耐皂洗色牢度均可达到4级以上。