Original Paper: Sol-gel and hybrid materials with surface modification for applications
Polyvinylamine-coated mesocellular silica foam (MCF) was synthesized by grafting poly(n-vinylformamide) (PNVF) followed by the acid hydrolysis of the formamide groups with hydrochloric acid (HCl) and subsequent neutralization with sodium hydroxide (NaOH). In order to graft PNVF, MCF silica was previously functionalized with the coupling agent vinyltrimehtoxysilane (VTMS). The PNVF content in the hybrid material was tailored by varying some reaction parameters such as monomer concentration, reaction time, and temperature. The grafted polymer content was determined by thermogravimetric analysis (TGA) and ranged from 27% to 50%. Additionally, small-angle X-ray scattering (SAXS), infrared spectroscopy (FT-IR), nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques confirmed the grafting of PNVF onto MCF. The N2 adsorption–desorption studies showed that the textural properties of the pristine MCF decreased as the amount of grafted PNVF increased confirming the deposition of polymer into silica. However, according to SAXS, SEM, and TEM studies, the mesostructure of MCF was maintained even after acid hydrolysis of PNVF and its subsequent neutralization to obtain PVAm.
Amine polymer/silica foam hybrid material was obtained.
Covalent grafting of PNVF onto mesocellular silica foam (MCF).
The content of the grafted PNVF was tailored by varying polymerization conditions.
Grafted PNVF turns into PVAm by acid-catalyzed hydrolysis.
Acid hydrolysis of PNVF does not affect the morphology of MCF.
This is a preview of subscription content, log in to check access.
This work was funded by the CONACYT-México (Fondo SENER-Hidrocarburos) under Grant no. 267962. H.I.M.-O. and G.C.-d.L. are particularly grateful to the program Cátedras-CONACyT (Mexico). Also, we thank to E.D. and J.A.C. from CIQA for their technical assistance.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.