Preparation and property of crosslinking guar gum

Abstract

The preparation and properties of crosslinking guar gum (GG) were studied by using ethanol as a solvent, epichlorohydrin as a crosslinking agent and sodium hydroxide as a catalyst. Some factors affecting the crosslinking degree of the crosslinked GG were investigated: reaction time, reaction temperature, amount of crosslinking agent, pH and solvent concentration. The sedimentation volume method was selected to determine the crosslinking degree of the crosslinked GG. The crosslinking degree was obviously influenced by the pH, reaction temperature and the crosslinking agent. The crosslinking improved alkali and acid resistance, retrogradation and viscosity stability of GG. The crosslinked GG has a significantly narrower melting transition as compared with GG. Polymer Journal ( It hydrates fairly rapidly in cold water, which gives highly viscous pseudoplastic solutions of generally greater low-shear viscosity. GG and its derivatives served as thickener, stabilizer, blister and flocculant are employed in the food, textile, pharmaceutical and paper industries due to their special properties. [1][2][3][4] Much effort has been devoted to the study of appropriate systems with special properties in order to avoid or minimize the side effects and to improve the efficacy of the therapy in the field of drug delivery in the last decades. Polysaccharides appear to be very attractive for their peculiar physico-chemical characteristics. 5 GG is hydrophilic and swells in cold water, forming viscous colloidal dispersions or sols. This gelling property retards the release of the drug from the dosage form, increasing the likelihood of degradation in the colon. GG was found to be a colon-specific drug carrier in the form of matrix and compression-coated tablets as well as microspheres. The drug is inevitably dissolved, at least partially, because of the high pH level in the stomach. The modification of GG with borax or glutaraldehyde results in a product that is degraded by the enzymatic mixture of galactomannanase and a-galactosidase, possessing a higher buffer-uptake capacity as compared with native GG. The polysaccharides are crosslinked to a sufficient extent that they remain insoluble in water. [6][7][8][9][10] GG can be modified by etherification, esterification, oxidation or graft. The derivatives of GG may compensate for the disadvantages of natural GG. For example, a carboxymethyl derivative may increase the hydrophilicity and solution clarity of the galactomannans and make it more soluble in an aqueous solution. The oxidized GG can be quickly

Co‐Crosslinked Water‐Soluble Biopolymers as a Binder for High‐Voltage LiNi0.5Mn1.5O4|Graphite Lithium‐Ion Full Cells

“…Nonetheless, the achievement of commercially relevant areal loading electrodes remains a great challenge in spite of the rather high amount of binder (≈5 wt %). Towards this end, guar gum (GG), a naturally available galactomannan‐based polysaccharide (repeated d ‐mannose units branched with glycosidic d ‐galactose side chains), has been identified recently as suitable alternative . Applications so far include alternative anode materials that follow an alloying or conversion‐type lithium storage mechanism as well as cathode materials such as lithium nickel manganese cobalt oxide (NMC) and its lithium‐rich derivative .…”

Technologies and Formulation Design of Polysaccharide-Based Hydrogels for Drug Delivery

“…The main problem is that the majority of covalent cross-linking agents are not biocompatible [ 4 , 84 ]. Among them, glutaraldehyde is certainly that with the longest history; it has been widely used to cross-link several biopolymers such as chitosan [ 85 , 86 ], sodium alginate [ 87 , 88 , 89 ], cellulose [ 90 , 91 ], guar gum [ 92 , 93 ], collagen [ 94 ], collagen-chitosan [ 95 ], alginate-guar gum [ 96 ], and carrageenan [ 97 , 98 ]. For instance, chitosan microspheres can be produced by mixing chitosan and glutaraldehyde solutions in oil containing surfactants [ 99 , 100 ].…”

Etherification optimization for preparing partially hydrolized hydroxypropylated guar gum and its properties

“…The calibration curve was showed in Figure . The propylene glycol concentration in the specimen was calculated from the standard curve and was converted to the equivalent hydroxypropyl groups from each molar solution using the following equations: where, MS, molar substitution degree; H , hydroxypropyl content, %; F , dilution multiple of sample and F was equal to 100; M sample , propylene glycol content of sample obtained from the standard curve, g; W sample , sample quality, g; M blank , propylene glycol content of blank sample obtained from the standard curve, g; W blank , sample mass of GG, g.…”

“…The viscosity of the sample changed slightly, which meant strong acid and alkali resistances. The measurement method of the acid and alkali resistances of GG was similar to that of the GG derivative …”