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The methylation process involves the substitution of hydroxyl (-OH) groups on the cellulose chain with methyl (-OCH₃) groups, which enhances the hydrophobic characteristics of the polymer. This substitution plays a critical role in determining the solubility and viscosity of HPMC in various solvents. The degree of substitution, which refers to the average number of hydroxyl groups replaced by methyl groups, greatly influences the properties of HPMC, such as its thickening ability and gel formation capacity.
chemical structure of hpmc

Pagkatapos ng alkalisasyon, ang cellulose ay hinaluan ng ethylene oxide (EO), isang reaktibong kemikal na nagdadala ng hydroxyethyl groups. Sa pamamagitan ng pagkokontrol sa temperatura at presyon sa panahon ng reaksyon, ang mga hydroxyethyl groups ay ikinakabit sa cellulose backbone. Ang proseso ng rekomendasyon ay nagsisimula sa mga temperatura sa pagitan ng 40-60 degrees Celsius, at kadalasang tumatagal ng ilang oras, depende sa nais na degree of substitution (DS) ng HEC.
hydroxyethyl cellulose synthesis

L'hydroxypropylméthylcellulose (HPMC) est une cellulose modifiée qui est largement utilisée dans divers secteurs en raison de ses propriétés uniques
. C'est un polymère semi-synthétique qui offre une variété d'applications industrielles, allant de l'alimentation à la pharmacie, en passant par la construction. Voici un aperçu des principales utilisations de l'HPMC.