Amine functionalization of microcrystalline cellulose assisted by (3-chloropropyl)triethoxysilane.

To improve the heavy metal adsorption of microcrystalline cellulose (MCC), two successive grafting reactions of silylation by (3-chloropropyl)triethoxysilane (CPTES) and amine-functionalization with metformin HCl were performed and the modified MCC from the first and second steps were denoted as MMCC-1 and MMCC-2, respectively. MMCCs were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) and compared to MCC. The presence of the amine group on the MMCC-2 surface was confirmed by FT-IR analysis. According to the XRD results, the crystallinity index (CI) of MMCC-1 increased very slightly compared to that of MCC that can be attributed to the partial hydrolysis of amorphous parts because of acidic conditions used for MCC silylation but CI of MMCC-2 decreased due to the high temperature and long time in the 2nd step of modification. TGA revealed the lower thermal stability of MMCC-2 than the corresponding MCC.