Synergistic Interaction and Gelation in Cationic Guar Gum-Sodium Alginate System

The synergistic interaction between the cationic guar gum (the ammonium hydroxy-propyl-trimethyl chloride of guar gum) and sodium alginate has been studied. The effects of the mass ratio of them, mixed temperature, balk salt ion concentration, incubation time and pH value on gelation were investigated. It has been observed that there was a gel strength maximum when the mass ratio was 0.6, the mixed temperature was 70°C, the balk salt ion concentration was 1.0 mol·L?1, the incubation time was 30 min and the pH value was 8. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry. Key words cationic guar gum - sodium alginate - gelation - synergism CLC number O 629.12 Foundation item: Supported by the National Natural Science Foundation of China(29574173)Biography: He Dong-bao (1945-), male, Associate professor, research direction: modifying and gelating of natural polysaccharides.

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.

Partially hydrolyzed guar gum attenuates non-alcoholic fatty liver disease in mice through the gut-liver axis

BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modulating gut microbiota.Partially hydrolyzed guar gum(PHGG),a water-soluble dietary fiber,has been reported to alleviate the symptoms of various intestinal diseases and metabolic syndromes.However,its effects on NAFLD remain to be fully elucidated.To determine whether treatment with PHGG attenuates NAFLD development in mice through the gut-liver axis.METHODS Seven-week-old male C57BL/6J mice with increased intestinal permeability were fed a control or atherogenic(Ath)diet(a mouse model of NAFLD)for 8 wk,with or without 5%PHGG.Increased intestinal permeability was induced through chronic intermittent administration of low-dose dextran sulfate sodium.Body weight,liver weight,macroscopic findings in the liver,blood biochemistry[aspartate aminotransferase(AST)and alanine aminotransferase(ALT),total cholesterol,triglyceride,free fatty acids,and glucose levels],liver histology,myeloperoxidase activity in liver tissue,mRNA expression in the liver and intestine,serum endotoxin levels in the portal vein,intestinal permeability,and microbiota and short-chain fatty acid(SCFA)profiles in the cecal samples were investigated.RESULTS Mice with increased intestinal permeability subjected to the Ath diet showed significantly increased serum AST and ALT levels,liver fat accumulation,liver inflammatory(tumor necrosis factor-αand monocyte chemotactic protein-1)and fibrogenic(collagen 1a1 andαsmooth muscle actin)marker levels,and liver myeloperoxidase activity,which were significantly attenuated by PHGG treatment.Furthermore,the Ath diet combined with increased intestinal permeability resulted in elevated portal endotoxin levels and activated toll-like receptor(TLR)4 and TLR9 expression,confirming that intestinal permeability was significantly elevated,as observed by evaluating the lumen-to-blood clearance of fluorescein isothiocyanate-conjugated dextran.PHGG treatment did not affect fatty acid metabolism in the liver.However,it decreased lipopolysaccharide signaling through the gut-liver axis.In addition,it significantly increased the abundance of cecal Bacteroides and Clostridium subcluster XIVa.Treatment with PHGG markedly increased the levels of SCFAs,particularly,butyric acid,acetic acid,propionic acid,and formic acid,in the cecal samples.CONCLUSION PHGG partially prevented NAFLD development in mice through the gut-liver axis by modulating microbiota and downstream SCFA profiles.

High molecular weight guar gum assisted settling of fine solids in diluted bitumen:Effect of solvents

As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical importance.However,the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining downstream.This research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE process.Herein,naturally hydrophilic additives(i.e.,water and high molecular weight guar gum(HGG)produced from Cyamopsiste tragonolobuosr L.Taup.)were introduced to promote the settling of fine solids suspended in bitumen-solvent solution,and the effects of solvents(i.e.,toluene,cyclohexane and their mixtures)were systematically investigated.Aggregate size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents studied.However,the size range and quantity of the agglomerates vary significantly with the solvent's aromatic character.Solvent mixtures demonstrate a superior performance on removing fine solids from bitumen over single solvent.Specifically,in a 3:2 toluene/cyclohexane mixture,the solid content was lowered from 0.66 wt%to 0.09 wt%.

Synthesis of Hydroxypropyl Guar Gum by Phase Transfer Catalysis

HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.

EFFECT OF ANIONIC SURFACTANT UPON THE VISCOSITY OF POLYMER GUAR GUM SOLUTIONS

The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate （SDBS） was measured. It has been found that the Huggins coefficient kH of polymer solutions is very sensitive to the concentration of the surfactant, CSDBS, in solutions. If CSDBS is lower than CMC, the critical micelle concentration of SDBS, kH increases rapidly with CSDBS. On the other hand, if CSDBS is larger than CMC, kH decreases rapidly with CSDBS. Comparatively, the intrinsic viscosity of polymer solution does not show a notable change with CSDBS. The experimental results indicate that the interchain association of polymer guar gum in solution is greatly associated with SDBS interacted with polymer chains through hydrogen bonds. However, the effect of SDBS upon the intrachain association of polymer guar gum solution is negligible, presumably due to the fact that guar gum is a slightly stiffened random-coil chain polymer.

INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS OF POLYMER GUAR GUM IN SOLUTIONS

The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c^＊, presented by de-Gennes, is determined successfully.

Analysis of the Factors Influencing the Solid-liquid Separation Experiment of Guar Gum Waste Liquid

Based on the water quality detection and analysis of guar gum waste liquid,as well as the data of experiments on the treatment of waste liquid under different viscosity and pH conditions,the influencing factors of solid-liquid separation under conventional"coagulation+filtration"treatment process are studied.Under the conventional"coagulation+filtration"treatment process,the viscosity of guar gum waste liquid is lower than 3 mPa·s;the pH is 6-7.5;the filtration accuracy is not lower than 20μm,which can meet better treatment conditions.This experimental study provides an experimental basis for the optimal design of the treatment process of guar gum waste liquid.

Microwave Assisted Synthesis of Guar Gum Grafted Acrylic Acid/Nanoclay Superabsorbent Composites and Its Use in Crystal Violet Dye Absorption

Natural gums can be tailored and used for the removal of toxic dyes like crystal violet via grafting techniques. However, grafting via microwave irradiation showed both higher yield and fast reaction kinetics as compared to conventional grafting. Silane modified nanoclay has been used to prepare acrylic acid grafted guar gum nanocomposites via microwave irradiation technique. The grafting was confirmed via infrared spectroscopy while XRD diffractograms suggested exfoliation of modified nanoclay in guar gum grafted acrylic acid. The reaction kinetic parameters have been optimized. The effect of nanoclay on swelling characteristics has been examined. The sensitivity of pH on swelling capabilities has also been assessed. The efficiency of the superabsorbent nanocomposite on the absorption of crystal violet dye has been studied. The superabsorbent nanocomposite loaded with 1.75% modified nanocaly was found to be optimal concentration for the removal of crystal violet dye.

In-depth understanding of transport behavior of sulfided nano zerovalent iron/reduced graphene oxide@guar gum slurry: Stability and mobility

Nanoscale zero-valent iron(NZVI),which has the advantages of small particle size,large specific surface area,and high reactivity,is often injected into contaminated aquifers in the form of slurry.However,the prone to passivation and agglomeration as well as poor stability andmobility of NZVI limit the further application of this technology in fields.Therefore,sulfided NZVI loaded on reduced graphene oxide(S-NZVI/rGO)and guar gum(GG)with shearthinning properties as stabilizers were used to synthesize S-NZVI/rGO@GG slurries.SEM,TEM,and FT-IR confirmed that the dispersion and anti-passivation of NZVI were optimized in the coupled system.The stability and mobility of the slurry were improved by increasing the GG concentration,enhancing the pH,and decreasing the ionic strength and the presence of Ca^(2+)ions,respectively.A modified advection-dispersion equation(ADE)was used to simulate the transport experiments considering the strain and physicochemical deposition/release.Meanwhile,colloidal filtration theory(CFT)demonstrated that Brownian motion plays a dominant role in themigration of S-NZVI/rGO@GG slurry,and the maximummigration distance can be increased by appropriately increasing the injection rate.Extended-Derjaguin-Landau-Verwey-Overbeek(XDLVO)theory showed that the excellent stability and migration of S-NZVI/rGO@GG slurry mainly came from the GG spatial forces.This study has important implications for the field injection of S-NZVI/rGO@GG slurry.According to the injection parameters,the injection range of S-NZVI/rGO@GG slurry is effectively controlled,which lays the foundation for the promotion of application in actual fields.

Fabrication and evaluation of carboxymethyl guar gum-chitosan interpenetrating polymer network (IPN) nanoparticles for controlled drug delivery

Guar gum(GG)has drawn more interest from researchers in the last several decades for the controlled delivery of drugs.The aim of the research is to fabricate and evaluate an interpenetrating polymer network(IPN)based nanocarriers system employing chemically modified GG to achieve controlled release of drug.In present study,we have reported the synthesis of carboxymethyl GG-chitosan IPN nanoparticles for controlled release of metformin hydrochloride.Carboxymethyl guar gum(CMGG)was synthesized and employed for developing IPN nanoparticles in combination with chitosan in varying polymeric ratios.A cross-linking agent,sodium tripolyphosphate(Na-TPP)was used for the synthesis of IPN colloidal suspension of nanoparticles which was lyophilized to obtain nanoparticles.The carboxymethylation of GG was confirmed through Fourier transform infra-red spectroscopy.The mean particle size was 440.6 nm indicating a polydispersity index of 0.528.The drug entrapment efficiency was found to vary between 67.461.64%to 88.232.02%.The differential scanning calorimetry study revealed the presence of amorphous metformin hydrochloride as a homogenous dispersion in nanoparticles(NPs)matrix.In vitro drug release study indicated controlled release ability of developed IPN matrix.A2 formulation(chitosan:CMGG-1:1)exhibited 78.110.27%release after 8 h.Antidiabetic evaluation performed in alloxan-treated diabetic rat model exhibited a prolonged hypoglycemic efficacy over 6 h,for A2 formulation treated group,compared to the group receiving only metformin HCl,which demonstrated a reduction in blood glucose levels for up to 4 h.The study findings demonstrated the efficacy of the CMGG-chitosan based IPN nanoparticulate system for sustained delivery of therapeutic agents.

Novel succinoylated carboxymethyl guar gum nanocarriers of glimepiride for controlling type-2 diabetes

In this study,guar gum(GG)was chemically modified to its carboxymethyl derivative,which was then esterified with octenyl succinic anhydride(OSA)using a nucleophilic catalyst 4-dimethylaminopyridine(DMAP)to render the derivative amphiphilic characteristics.The carboxymethyl guar gum(CMGG)and succinoylated CMGG was characterized using Fourier transform infrared spectroscopy(FTIR)spectroscopy.The amphiphilic CMGG synthesized using DMAP/OSA ratio of 0.5:1(CMGGOSA-I),was found to be non-toxic.The amphiphilic guar gum self-assembled in water to form nanocarriers with mean diameter of 430 nm and zeta potential of19.0 mV.Transmittance electron microscope(TEM)image showed spherical nature of the developed CMGGOSA-I nanocarriers.In presence of amphiphilic CMGG,the aqueous solubility of glimepiride was enhanced by about 67-fold.The nanocarriers released glimepiride in simulated gastrointestinal fluids for a period of more than 24 h,following Higuchi's kinetics.Korsmeyer-Peppas modeling of the drug release data revealed that a combination of swelling and diffusion mechanism was operative in the event of drug release.In streptozotocin-induced diabetic rat model,the nanocarriers outperformed pure drug suspensions in terms of anti-diabetic activity,which lasted up to 24 h.Overall;the newly synthesized amphiphilic CMGG nanocarriers demonstrated controlled drug release properties and showed promise for controlling type-2 diabetes.

Destabilization of bitumen-coated fine solids in oil through water-assisted flocculation using biomolecules extracted from guar beans

Non-aqueous extraction(NAE)of bitumen from oil sands has been gaining great attention from both the industry and academia as an alternative to the water-based extraction.A fine solids removal step is important for a NAE process in order to obtain high-quality bitumen product,which,however,remains a great challenge to reduce the fine solids content to the desired level.Here,we introduce a strategy of destabilizing the bitumen-coated silica particles in toluene with the addition of water and biomolecules extracted from Cyamopsiste tragonolobuosr L.Taup.,i.e.,high molecular weight guar gum(HGG)and low molecular weight guar gum(LGG),respectively.By virtue of sedimentation tests and focused beam reflectance measurement analysis,we demonstrate that the introduced water droplets modified with these biomolecules can facilitate the settling of the solid particles in toluene although the underlying mechanisms differ between these two biomolecule cases.Specifically,in the case of LGG,the added water droplets with the interfacial amphiphilic LGG can strengthen the attachment of solid particles from bulk toluene to the LGG surface.This research work provides useful insight into the development of effective approaches for destabilization and removal of bitumen-coated fine solids from NAE bitumen.

A dural substitute based on oxidized quaternized guar gum/porcine peritoneal acellular matrix with improved stability, antibacterial and anti-adhesive properties

Trauma and neurosurgery often result in dural defects and are followed by serious complications or even death, finding suitable dural replacement materials to repair the defective dura has important clinical significance. Porcine peritoneal acellular matrix(PPAM) is a promising alternative material, but its poor stability makes it difficult to meet the various needs of dural reconstruction. In this work, we developed a novel antibacterial cross-linking agent oxidized quaternized guar gum(OQGG) and used it for the first time to stabilize PPAM to construct a dural mater substitute(OQGG-PPAM). The results showed that 1.5%OQGG-PPAM presented suitable mechanical property as well as good thermal stability and resistance to enzymatic degradation. It also exhibited good antibacterial activity and good anti-leakage ability. Furthermore, 1.5% OQGG-PPAM not only exhibited excellent cell compatibility but also significantly stimulated the secretion of b FGF and VEGF from seeded cells which was convenient for dural remodeling. In vivo experiment, it also exhibited the excellent histocompatibility and good anti-adhesion property. This study showed that OQGG can be used as a novel antibacterial cross-linking reagent for crosslinking natural tissues and 1.5% OQGG-PPAM was a potential candidate material for dura mater substitute.

Development and application of guar gum crosslinked gel with adjustable gelation time for total loss treatment

To remediate the problem of severe or total losses,and meet the requirements of borehole plugging and pumping at different well depths,a novel crosslinked polymer gel(named HPG/Zr gel)with controlled gelation time and high gel strength was developed as loss circulation material,which mainly comprised hydroxypropyl guar gum,zirconium compound and triethanolamine.The influence of hydroxypropyl guar gum concentration,zirconium compound concentration,triethanolamine concentration and temperature on the gelation time of HPG/Zr gel was evaluated.In addition,the performance of HPG/Zr gel was investigated in terms of temperature resistance and shear resistance property,plugging ability and supporting cement slurry ability.According to the results,HPG/Zr gel can form a viscoelastic body with a network structure,and its gelation time can be practically adjustable.The results of the plugging experiment at different temperatures,pressures and pore sizes of quartz sand revealed that HPG/Zr gel could effectively plug sand pores at 150℃,and its pressure-bearing capacity can be up to 5 MPa.Employing its flow resistance and ability of supporting cement slurry,HPG/Zr gel was successfully applied in two geological boreholes by combining with cement slurry.Overall,the results of laboratory research and field tests indicate that HPG/Zr gel is useful for mitigating the lost circulation,and it is of huge importance to engineering applications.

阳离子瓜尔胶在轻型纸中的应用

介绍了阳离子瓜尔胶(CGG)与阳离子聚丙烯酰胺(CPAM)组成的双元助留助滤体系在轻型纸生产中的使用情况。通过CPAM/CGG双元助留助滤体系与单元CPAM助留助滤系统和CPAM/APAM(阴离子聚丙烯酰胺)双元助留助滤体系的对比,确定CPAM/CGG双元助留助滤体系更适合于轻型纸。当CPAM/CGG双元助留助滤体系中的CPAM、CGG用量均为0.4 kg/t(纸)时,其使用效果明显。

高pH下邻菲罗啉金属配合物催化氧化降解羟丙基瓜尔胶

为了获得高pH条件下Fenton体系的高效催化剂,选取了Fe^(2+)、Fe^(3+)、Co^(2+)、Ni^(2+)、Cu^(2+)、Zn^(2+)六种常见金属离子与邻菲罗啉(L)在摩尔质量分别为0.2 mol/L下等体积混合制备了配合物Fe(Ⅱ)L、Fe(Ⅲ)L、CuL、CoL、NiL和ZnL,评价了这6种配合物作为催化剂在高pH条件下催化H_2O_2氧化降解羟丙基瓜尔胶的效果。结果表明,该系列配合物都有一定的催化效果,其中CuL的催化效果最佳,在pH7.0~14.0的范围内均具有较好的催化效果。CuL催化H_2O_2降解羟丙基瓜尔胶的作用良好,在温度45℃、pH10、H_2O_2加量为羟丙基瓜尔胶质量的10.0%,催化剂CuL加量为H_2O_2质量5.0%的情况下降解反应40 min后,羟丙基瓜尔胶体系的相对黏度由14降低至1.2,与水黏度接近,相对分子质量从200万降至2864,COD值从22.49 g/L降至8.73 g/L,增加双氧水加量为羟丙基瓜尔胶质量的25.0%,降解4 h可将COD值降至41 mg/L。

青海油田低浓度胍胶压裂液的性能研究与现场应用

开发了稠化剂浓度为0．18％-0．20％的低浓度胍胶压裂液体系，使稠化剂浓度比常规胍胶压裂中的稠化剂浓度低40％-50％，单方液成本降低30％-38％。通过对该低浓度胍胶压裂液的性能评价，确定了该体系具有良好的耐温耐剪切性能和滤失性能，破胶快速彻底。岩心损害率为22．53％，压裂液残渣含量仅为226．3mg／L，为常规胍胶压裂液的一半，大大降低了压裂液残渣对裂缝导流能力的损害。2012年，低浓度胍胶压裂液体系在青海油田应用总井数87井次，累计降低成本403．7万元，其中在昆北区块应用55井次，增产倍数为该区块2011年压裂井的1．08倍，降本增产效果明显。

超低浓度羟丙基瓜尔胶压裂液体系

为符合低成本、低伤害、环保绿色开发的理念,针对低渗透储层特点,利用长链多点螯合技术,增加交联剂链的长度,研发了高效交联剂;针对煤层气井温度低(20~40℃)、破胶困难等难题,开发了三元复合破胶技术;形成了30~163℃压裂液系列配方体系,相同温度条件下,稠化剂用量降低30%~50%,对储层的伤害率降低了30%~40%,材料成本降低30%以上,实现稠化剂交联下限至0.10%。在长庆油田、冀东油田、华北油田、吐哈油田、煤层气田等推广应用979井1368层(段),施工成功率100%,试验井产量分别为对比井的2.5~5.3倍,展示出良好的应用前景,为低渗特低渗油气藏、致密油气藏的高效开发提供技术保障。

羟丙基瓜胶压裂液超低温破胶系统研究

对埋藏浅、油层温度低的油藏进行压裂改造，需要解决压裂液低温破胶化水问题。本文提出了过硫酸铵／激活剂Ｍ低温破胶系统，研究了采用该系统的低温破胶羧丙基瓜胶压裂液的配方、破胶化水及性能，介绍了该配方压裂液在延长油田（油层温度３０─５０℃进行４４井次现场试验的结果。