Various characteristics and catalytic performance of iron (II) phthalocyanine immobilized onto titania- and vanadia-pillared bentonite clay in in situ polymerization of methyl methacrylate: An attempt to synthesize novel polymer/iron phthalocyanine/pillar

Pure bentonite clay has been modified through acid thermal treatment (ATTB) and by pillaring with titania and vanadia (Ti-PILB and V-PILB). Iron (II) phthalocyanine complex (FePc) was immobilized in 0.5 wt% loading on the modified bentonite supports. Structural characteristics were investigated through XRD, FTIR and ICP-EDX techniques. Textural and morphological characteristics were estimated from adsorption–desorption isotherms of N2, pore size distribution analysis and SEM. Dispersion parameters of FePc molecules were determined from H2 chemisorption isotherms at 300 °C. Cation exchange capacities and acid–base behaviours were also studied. Incorporation of oriented FePc was found to reorganize the clay layer stacking, being deformed upon modification, through interaction with pillar (in V-PILB) or with interlayer sites (in Ti-PILB). Catalytic performance of different samples in in situ bulk polymerization of methyl methacrylate at 60 °C was discussed, where living polymerization mechanism, within the role of FePc in re-initiation of dormant polymer molecules, was confirmed. M¯w and M¯n of produced polymers decreased, according to the used support, in the order: Ti-PILB > ATTB > V-PILB, the same decreasing order of chain transfer constant (CT), related to contribution of FePc. A new approach for synthesis of polymer/modified bentonite composites of partially exfoliated layers was provided. In PMMA/FePc/V-PILB composite, nanoclay particles (of 25 nm) were shown with more ordered polymer chains and well dispersed vanadia pillar species, in a strong interaction and high compatibility with FePc.

Vanadia in V-PILB (a, 27–163 nm), dissociated into nanoparticles (b, 12–19 nm) through interaction with FePc, produced exfoliated PMMA/complex/clay composite of nanoclay particles (c, 25 nm) and dispersed vanadia, highly compatible with FePc. 33.Figure optionsDownload high-quality image (126 K)Download as PowerPoint slideResearch highlights▶ Characterization of the modified bentonite, viz., through acid thermal treatment (ATTB) and by pillaring with titania and vanadia (Ti-PILB and V-PILB), as well as the hybrid catalytic system of Fe (II) phthalocyanine (FePc) immobilized onto modified clay samples (in 0.5 wt%, of diluted loading region). ▶ Following up catalytic performance of these systems in the in situ polymerization of MMA at 60 °C, in absence of a cocatalyst, aiming to elucidate the competing roles played by the complex, the pillars and the interlayer sites in the reaction mechanism, compared with other phthalocyanine systems. ▶ An attempt to synthesize novel PMMA/FePc (compatibilizer)/pillared clay (filler) nanocomposites, as polymerization end products.