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Mechanics of gelation describes processes relevant to sol-gel process. In a static sense, the fundamental difference between a liquid and a solid is that the solid has elastic resistance against a shearing stress while a liquid does not. Thus, a simple liquid will not typically support a transverse acoustic phonon, or shear wave. Gels have been ...
Differential scanning calorimetry (DSC) is another method industries use to examine properties of gelatinized starch. As water is heated with starch granules, gelatinization occurs, involving an endothermic reaction. [8] The initiation of gelatinization is called the T-onset. T-peak is the position where the endothermic reaction occurs at the ...
Alkoxides are ideal chemical precursors for sol–gel synthesis because they react readily with water. The reaction is called hydrolysis, because a hydroxyl ion becomes attached to the silicon atom as follows: Si(OR) 4 + H 2 O → HO−Si(OR) 3 + R−OH. Depending on the amount of water and catalyst present, hydrolysis may proceed to completion ...
Random graph theory of gelation is a mathematical theory for sol–gel processes.The theory is a collection of results that generalise the Flory–Stockmayer theory, and allow identification of the gel point, gel fraction, size distribution of polymers, molar mass distribution and other characteristics for a set of many polymerising monomers carrying arbitrary numbers and types of reactive ...
An inexpensive, non-toxic example of a non-Newtonian fluid is a suspension of starch (e.g., cornstarch/cornflour) in water, sometimes called "oobleck", "ooze", or "magic mud" (1 part of water to 1.5–2 parts of corn starch). [22] [23] [24] The name "oobleck" is derived from the Dr. Seuss book Bartholomew and the Oobleck. [22]
Much rarer are hydrogels, or gels that form with water as the solvent. [14] Several attempts have been made to quantify the gel and solvent interaction using a variety of parameters: The single or multi-component solubility parameter (δ) of a solvent can give insight on how well-suited the solvent will be for gelation. Depending on the gelator ...
Retrogradation can expel water from the polymer network. This process is known as syneresis. A small amount of water can be seen on top of the gel. Retrogradation is directly related to the staling or aging of bread. [3] Retrograded starch is a type of resistant starch. Chemical modification of starches can reduce or enhance the retrogradation ...
Typically, gels are synthesized via sol-gel processing, a wet-chemical technique involving a colloidal solution (sol) that acts as the precursor for an integrated network (gel). There are two possible mechanisms whereby organogels form depending on the physical intermolecular inter-actions, namely the fluid-filled fiber and the solid fiber ...