Synthesis of Inorganic/Organic Host−Guest Hybrid Materials by Cationic Vinyl Polymerization within Y Zeolites and MCM-41

Abstract

Cationic guest polymerizations of several vinyl monomers inside the pores of HY zeolites and MCM-41 as hosts have been used for the synthesis of novel organic/inorganic hybrid materials. Substituted vinyl ethers [ROCHCH2; R = −CH2CH(CH3)2, −C2H5, −C2H4Cl, −C6H11], 2,3-dihydrofuran, and N-vinylcarbazole can serve this purpose, because their polymerization can be initiated by the active protons in HY zeolite or by coadsorbed arylmethylium ions in MCM-41. The synthesis of well-defined poly(vinyl ethers) or poly(vinylcarbazole) under the conditions of constricted geometry can be achieved by means of cationic host−guest polymerization of the corresponding monomers in MCM-41 (pore diameter 3.6 nm) with (4-CH3OC6H4)2CHCl (MeO) or (C6H5)3CCl (TC) as the internal surface initiator. The reaction products are novel polymer/MCM-41 host−guest hybrid materials. The molecular mass of the (enclosed) polymer and the percentage of polymer within the pores of MCM-41 as well as HY zeolite can be adjusted within certain limits. Polymeric products are analyzed by solid-state magic angle spinning cross-polarization 13C{1H} NMR spectroscopy and gel permeation chromatography analyses of the obtained polymer fraction after dissolution of the hybrid material in an aqueous potassium hydroxide solution. The formation of conjugated sequences of poly(vinyl ether) segments inside the HY zeolites is caused by successive ether cleavage along the encapsulated polymer chains.

Monomer- and polymer radicals of vinyl compounds: EPR and DFT studies of geometric and electronic structures in the adsorbed state

“…Polymerization of vinyl monomers can be initiated by acidic protons in the H-form of the zeolite or by co-adsorbed arylmethylium ions in MCM-4 silica [22]. In order to control 5 polymerization reactions, the surface of the MCM-41 mesoporous silica can be modified (functionalized) with different organic groups [23].…”

Properties of PVDF-MCM41 Nanocomposites Studied by Dielectric, Raman and NMR Spectroscopy

“…M41S molecular sieves are another kind of mesoporous filler having one dimension in the nanometer scale with variety of important applications [17]. MCM-41, one member of the M41S family, with hexagonal arrangement of channel-like pores of diameters between 1.5 and 10 nm is especially exploited in preparation of inorganic oxide -organic polymer nanocomposites [18][19][20][21]. Ferroelectric polymers like poly(vinylidenefluoride) (PVDF) have attracted much attention as the matrix for polymer-inorganic nanofiller composites because due to their piezo-and pyroactivity both sensing and actuating functions can be realized in the same element [22,23].…”

Isotropic concentration profiles during diffusion-limited desorption from anisotropic media

“…This is of particular relevance for deviations from the ideal ("text-book") structure of the media under study, which by other techniques like X-ray diffraction or porosimetry are often scarcely to be detected. Thus, the imaging techniques represent a valuable supplement within the arsenal of techniques of structure determination [9][10][11].…”