نوع مقاله : پژوهشی
تبریز، دانشگاه تبریز، دانشکده شیمی، گروه شیمی آلی، کد پستی 16471-51666
عنوان مقاله [English]
Co-precipitation method was employed for the intercalation of carboxymethyl cellulose (CMC) into layered double hydroxide (LDHs) sheets and preparation of CMC-LDH nanocomposites. CMC-LDH nanocomposites were synthesized by a reaction of basic solution of CMC with the mixed aqueous metallic salt solutions of M2+ (M2+ = Mg and Ni)/Al3+ ratio of 2. The structure and morphology of the synthesized CMC-LDH nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transition electron microscope (TEM) and thermal gravimetric analysis (TGA). Furthermore, the swelling behavior of the nanocomposites was studied in aqueous solutions of various pH. The intercalation of carboxymethyl cellulose polymeric chains into the LDH sheets was confirmed by FTIR spectroscopy and XRD analysis. The interlayer distance of Mg-Al-CMC-LDH and Ni-Al-CMC-LDH nanocomposites was found to be 1.73 and 2.23 nm, respectively. The XRD patterns confirmed a multilayer arrangement of CMC polymeric chains between the LDH sheets. TEM analysis revealed a highly intercalated morphology for the nanocomposites, which was agreed with XRD data. Thermal gravimetric analysis showed a better thermal resistance of carboxymethyl cellulose in the presence of LDH sheets, especially for Mg-Al-CMC-LDH. Thermal stability of CMC in the nanocomposites increased for about 50°C and 133°C for Ni-Al-CMC-LDH and Mg-Al-CMC-LDH, respectively. The obtained nanocomposites revealed a pH-dependent swelling behavior. The swelling of the prepared nanocomposites increased slowly with increasing the pH from 2 to 10. However, their swelling ratio increased sharply in pH values above 10.