A Facile Synthesis of PMMA-SiO₂ Nanocomposites via Surface Initiated Radical Polymerization

Abstract

Well-defined core–shell structured poly(methyl methacrylate) grafted silica nanocomposites (PMMA-g-SiO₂) were synthesized via thiol-lactam initiated radical polymerization by employing a grafting from protocol. Spherical SiO₂ nanoparticles were reacted with 3-mercaptopropyl-trimethoxysilane in order to prepare thiol functionalized SiO₂ nanoparticles (SiO₂-SH). Subsequently, the surface initiated polymerization was accomplished by using two component initiating system comprising SiO₂-SH and butyrolactam. The anchoring of PMMA onto the surface of SiO₂ nanoparticles was ascertained by FTIR and XPS analyses. A uniform and spherical core-shell structure of PMMA-g-SiO₂ was revealed from TEM and SEM images. The GPC analysis demonstrated that the molecular weight of PMMA was a function of both monomer conversion and polymerization time. DLS also confirmed that the hydrodynamic diameter of the nanocomposites was directly related to the polymerization time. An improved thermal property of the polymer matrix with incorporating SiO₂ nanoparticles was revealed by TGA study.

Keywords:

• Silica nanoparticles
• poly(methyl methacrylate)
• hybrid nanocomposites
• polymer brush
• core-shell
• surface initiated polymerization

Acknowledgments

This work was financially supported by the Joint Program of Cooperation in Science and Technology through NRF grant funded by the MEST (no. 2011-0025680) and the grant from the Industrial Source Technology Development Program (Project No.10035163) of the Ministry of Knowledge Economy (MKE) of Korea.