Investigation of the Physicochemical Behavior of a Thermosensitive Hydrogel Based on Carboxymethyl Cellulose (CMC) with Phosphate–Calcium Microfillers

This study explores the physicochemical behavior of a heat-responsive hydrogel composite produced from carboxymethyl cellulose (CMC) and poly(N-isopropylacrylamide) (pNIPAAm), additionally reinforced with calcium phosphate microfillers. The purpose of the work was to design and evaluate a polymer material capable of rapidly absorbing water while providing controlled ion release. The hydrogel was synthesized through free-radical copolymerization under gentle heating, which supported the formation of a semi-interpenetrating network strengthened by ionic interactions between CMC functional groups and the mineral additives. Swelling tests have shown that the material absorbs a significant amount of water at temperatures below the lower critical solution temperature (LCST), and absorption clearly decreases after temperatures above approximately ۳۰-۳۴ °C, indicating temperature-related structural changes. Thermal analysis (TGA/DSC) showed a multi-stage decomposition pattern typical of cellulose-synthetic polymer systems, with the main decomposition occurring at temperatures between ۲۵۰ and ۴۵۰ °C. The porous polymer and mineral structure, which are well interconnected through microscopic studies, were determined by these studies. By adding calcium and phosphate to the composition, the mechanical integrity of the polymer was strengthened, increasing its ability to retain moisture and enhancing its applicability.

کلیدواژه ها:

Hydrogel ، Thermoresponsive polymer ، carboxymethyl cellulose ، Poly(N-isopropylacrylamide) ، Physicochemical behavior