INTRODUCTION OF A DOUBLE BOND CONTAINING MODIFIER ON THE SURFACE OF MCM-41 NANOPARTICLES: APPLICATION FOR SR&NI ATRP OF STYRENE

Abstract

Mesoporous silica nanoparticles (MCM-41) surface was functionalized with 3-(trimethoxysilyl) propyl methacrylate (MPS). Then, the resultant double bond containing nanoparticles were used in grafting through simultaneous reverse and normal initiation technique for atom transfer radical polymerization (SR&NI ATRP) of styrene to synthesize well-de¯ned polystyrene nanocomposites with twofold chains. Nitrogen adsorption/desorption isotherm and X-ray di®raction analysis were used to evaluate characteristics of spherical MCM-41 nanoparticles. Morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography respectively. Addition of MCM-41 nanoparticles by 3 wt.% results in a decrease of conversion from 93% to 82%. Molecular weight of the free and attached polystyrene chains decreases by adding 3 wt.% MCM-41 nanoparticles; however, PDI values increases from 1.27 to 1.78 for free chains and 1.87 to 2.48 for attached chains. A peak around 4.1 ppm which originates from hydrogen atom of terminal units of polystyrene chains in proton nuclear magnetic resonance spectra in combination with low PDI values can appropriately demonstrate the living nature of the polymerization. Increasing thermal stability of the nanocomposites is demonstrated by Thermogravimetric analysis. Di®erential scanning calorimetry also shows a decrease in glass transition temperature by increasing MCM-41 nanoparticles.

SR&NI atom transfer radical random copolymerization of styrene and butyl acrylate in the presence of MPS-functionalized silica aerogel nanoparticles

“…Silica/polymer nanocomposites have many potential applications as aerospace materials, structural materials, electronic, and sensors [8]. Direct mixing of polymers with silica particles or silica precursors, direct mixing of monomers with silica particles followed by polymerization of the monomers, and mixing both silica precursors and monomers followed by simultaneous polymerization of precursors and monomers are three main synthetic procedures to produce the silica/polymer nanocomposites [8,9].…”

Confinement effect of graphene nanoplatelets on atom transfer radical polymerization of styrene: grafting through hydroxyl groups

“…This method can result in high degree of control over the density of functionalization. Second, "grafting through" which is based on the attachment of a double bond-containing material on the surface and its subsequent incorporation into the polymer chains [9,10]. Grafting through the monomer units anchored on the surface cannot be controlled like surfaceinitiated polymerization.…”

Effect of MCM-41 nanoparticles on ARGET ATRP of styrene: Investigating thermal properties

“…MCM-41 nanoparticles as an impurity can increase chain transfer and termination reaction of propagating radicals, and therefore broadens molecular weight distribution of the resultant polymers. 39,40 Suitable agreement between the theoretical and experimental molecular weights implies the controlled nature of the polymerization reaction. Also, the color change of reaction media during polymerization (from green to brown) can be considered as an appropriate evidence of ATRP equilibrium establishment.…”

“…[13][14][15] Separation of proteins, usage in chromatography, selective adsorption of large molecules from effluents, and catalyst support are some examples for various applications of MCM-41 nanoparticles. [16][17][18] Synthesis of polymers with precise control over molecular weight and structure is a long-standing goal for polymer chemists. Although living anionic polymerization can be considered as a robust way for the preparation of polymer with low polydispersity indexes (PDIs), controlled radical polymerization (CRP) methods provide some special features since they combine benefits of living anionic polymerization and free radical polymerization (FRP).…”