3-Aminopropyltriethoxysilane-mediated (phenoxy-imine) polymers: synthesis and characterization

Abstract

3-Aminopropyltriethoxysilane (3-APTES)-functionalized phenoxy-imine polymers exhibiting enhanced thermal properties have been synthesized by oxidative polycondensation using 4-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxybenzaldehyde and 3,4-dihydroxy benzaldehyde; subsequently, the polymerized aldehydes polymers were grafted by integrating 3-APTES to form poly(imine)s. All compounds characterized by FT-IR, UV–Vis, 1H-NMR and XPS analyses revealed the existence of Si–O–C bonds in the silanized compounds. Thermal behavior (TG–DTA–DSC) of the synthesized polymers has been determined using thermogravimetric and differential scanning calorimetry techniques. The thermal stability of the phenoxy-imine polymers was enhanced significantly by incorporation of 3-APTES into the polymer backbone. Size exclusion chromatography provided information about the number average molecular weight (Mn), weight average molecular weight (Mw) and polydispersity index values of phenoxy-imine polymers. Photoluminescence and morphologic properties of the polymers at different amplifications were analyzed. The results of optical, thermal and electrical conductivity measurements indicated that the phenoxy-imine polymers were crucial due to their high electrical conductivity and heat retardancy as well as the lowest band gap for P3 derived from 2-hydroxy-1-naphthaldehyde and 3-APTES. 3-Aminopropyltriethoxysilane-functionalized phenoxy-imine polymers were synthesized using the polymerized aldehydes. The results of optical, thermal and electrical conductivity measurements indicated that the phenoxy-imine polymers were crucial due to their highest electrical conductivity and heat retardancy as well as the lowest band gap for P3 derived from 2-hydroxy-1-naphthaldehyde and 3-aminopropyltriethoxysilane.