Copolymerization of methyl methacrylate with 4‐vinylpyridine initiated by a novel Ni(II)α‐Benzoinoxime complex

Abstract

Copolymerizations of methyl methacrylate (MMA) with 4-vinylpyridine (4VP) were performed from different monomer feed ratios in 1,4-dioxan at 308C under free radical initiation experimental conditions, using Ni(II)a-Benzoinoxime complex as initiator. The obtained copolymers (PMMA4VP) were examined by FTIR and 1 H NMR spectroscopies. The composition of these copolymers was calculated, using 1 H NMR spectra and elemental analysis. Monomer reactivity ratios were estimated from Fineman-Ross (FR, r m 5 0.550, r v 5 1.165) and Kelen-Tudos (KT, r m 5 0.559, r v 5 1.286) linearization methods, as well as nonlinear error in variables model (EVM) method using the RREVM computer program (RREVM, r m 5 0.559, r v 5 1.264). These values suggest that MMA-4VP pair copolymerizes randomly. 1 H NMR spectra provide information about the stereochemistry of the copolymers in terms of sequence distributions and configurations. These results showed that the age of the Ni complex has an impact not only on its activity towards polymerization reactions but also on the features of the corresponding copolymers, whereas the chemical composition was insensitive to this prominent factor. The mechanism of MMA-4VP copolymerization is consistent with a radical process as supported by microstructure and molecular weight distribution studies. Thermal behaviours of these copolymers were investigated by differential scanning calorimetry and thermogravimetric analysis.

Elaboration and thermal analysis of nanocomposites based on poly(methyl methacrylate‐co‐4‐vinylpyridine) and Maghnia bentonite

“…PMM4VP32 copolymer previously synthesized 19 was purified again and recharacterized in this study as a film cast from THF that may still contain some solvent traces or moisture even though dried for several days. Its T g determined by a different DSC apparatus, under nitrogen at a different scanning rate of 10°C/min, decreased compared to the previous one determined under different conditions and as a precipitate…”

“…PMM4VP32 was characterized as previously 19 reported by UV spectroscopy, 1 H‐NMR and 13 C‐NMR spectra performed on a Bruker 500 MHz spectrometer at room temperature with CDCl 3 as the solvent and tetramethylsilane (TMS) as internal standard and elemental analysis. Its weight average molecular weight and polymolecularity obtained by size exclusion chromatography were of 6.2 × 10 3 and 1.67, respectively.…”

“…X‐ray diffractograms of pure bentonite (PBT) and modified Maghnia bentonite (OBT), virgin PMM4VP32 copolymer and its PMM4VP32/OBT (in presence of 2 and 4% by weight of (OBT) were recorded on a Philips PW3710 diffractometer in the range of 2 Theta (2–50).…”

“…We have in a previous study prepared intercalated nanocomposite, with enhanced thermal stability, based on poly(methyl methacrylate) and an organically modified bentonite (from Algeria) via in situ intercalative polymerization initiated by a neutral Ni(II)α‐benzoinoxime complex (NBO) as a single component initiator in dioxan at room temperature 18 . Copolymers of various compositions of 4‐vinyl pyridine and methyl methacrylate of increased glass transition temperatures ( T g s) and enhanced thermal stability were successfully prepared at 30°C using this complex (NBO) as a single component initiator 19 . These types of copolymers are of importance as reported in the literature by several authors 20–23 as candidates in several applications as polyelectrolytes and catalyst supports.…”

Elaboration and thermal behavior of nanocomposites based on poly(ethyl methacrylate) and an Algerian bentonite prepared via in situ polymerization initiated by Ni(II)α-benzoinoxime complex

“…It is soluble in common organic solvents, air and moisture stable and can be handled easily in open air. This complex was used as a single component initiator via radical redox mechanism at room temperature in the synthesis of poly(methyl methacrylate) [15], various poly(methyl methacrylate-co-4-vinylpyridine) [16]. It was also successfully used in the elaboration of mainly intercalated nanocomposite based on poly(methyl methacrylate) [17] and a 3% by weight of a bentonite, originated from Algeria, organically modified by hexadecyl ammonium salt (HDA), via in situ intercalative polymerization in dioxan at room temperature.…”