ABSTRACT
In recent years, the polymer/inorganic nanocomposites have achieved vast consideration.1-4 These organic/inorganic hybrid (nano)materials contain and mix at the same time properties of the organic components and inorganic components, which offer more superior structure and properties. Many researchers have assigned multiple affords to construct and characterize organic/inorganic hybrid (nano) materials.4-6 Among the numerous inorganic nanollers, nanosilica is the most generalized ller reported in the literature. It has obtained much consideration in recent years and has been engaged in the variety of applications.7 The immobilization of the polymer chains chemically grafted
to a solid surface is generally done using either the grafting to or grafting from routes.8,9 The grafting to method needs to tether end-functionalized polymer chains directly on a surface via a chemical reaction of the end groups with the existing groups on the attaching surface.10,11 This method is experimentally simple but it owns some restrictions. This method often travails from low grafting density and lm thickness because of the problems of polymer molecule diffusion through an existing attached polymer layer to attain the reactive sites. Hence, steric hindrance for surface grafting increases along with an addition in the polymer lm width. On the other hand, grafting from approach has been considered as one of the best alternatives for the synthesis of the polymer brushes via chemisorption approach.12,13
Introduction ............................................................................................................................................................................... 347 Carboxylated Hydrophilic Polymer/Silica Hybrid Nanoparticles ............................................................................................ 348
Synthesis .............................................................................................................................................................................. 348 Anchoring of Amine Groups onto FSN ........................................................................................................................... 348 Synthesis of Carboxylated Hydrophilic Polymer/FSN Hybrid Nanoparticles ................................................................ 349
Characterization ................................................................................................................................................................... 349 FT-IR Analysis................................................................................................................................................................. 349 TG Analysis ..................................................................................................................................................................... 349 DLS and SEM Analyses .................................................................................................................................................. 350
Sulfonated Hydrophilic Polymer/Silica Hybrid Nanomaterials ............................................................................................... 350 Synthesis .............................................................................................................................................................................. 350 Characterization ................................................................................................................................................................... 350
FT-IR Analysis................................................................................................................................................................. 350 TGA ................................................................................................................................................................................. 351 TEM, SEM, and DLS Observations ................................................................................................................................ 351
Sulfonated Hydrophilic Polymer-Grafted SNs Used in the Proton Exchange Membranes ...................................................... 352 Membrane Preparation ......................................................................................................................................................... 352 Membrane Properties ........................................................................................................................................................... 352
Water Uptake and Proton Conductivity ........................................................................................................................... 352 Morphology ..................................................................................................................................................................... 352 Mechanical Properties ..................................................................................................................................................... 353
Conclusion ................................................................................................................................................................................ 353 References ................................................................................................................................................................................. 353
This method utilizes the surface of immobilized initiator followed by in situ polymerization to render polymer brush. The active end centers of the growing chains are easily available for monomer units. The advantage of the grafting from method over the grafting to method is that the rmly tethered polymer chains with excellent graft density are grown from the solid surfaces.14 A wide variety of synthetic ways for the production of polymer brushes via the grafting from procedure have been built upon controlled polymerization methods including cationic and anionic polymerization,15,16 ring-opening polymerization,17,18 ring-opening metathesis polymerization,19,20 atom transfer radical polymerization,21,22 nitroxide-mediated polymerization,23,24 and polymerization via reversible addition fragmentation chain transfer.25,26
Most studies on the grafting from method have been done through conventional free-radical polymerization.27-30 Azo and peroxide initiation systems are frequently utilized in this method.29 On the other hand, redox initiation is an efcient approach to generate free radicals under mild conditions and is used in low-temperature polymerizations. Redox polymerization has multiple benets such as very short induction time, low activation energy (40-85 kJ mol−1), the production of high-molecular-weight polymers with high efciency, and simple control of the polymerization reaction at the low temperature due to the reduced side reactions.29,31 Ce(IV),32,33 Fe(III),29,32 and Mn(III)29,34-36 salts form wellknown redox initiation systems when they are used along with different organic agents such as alcohols, amines, aldehydes, ketones, acids, and thiols for the (co)polymerization of vinyl monomers like acrylonitrile and acrylamide in the aqueous medium.
