Catalytic Polymerization of Methyl Methacrylate in Different Media Using Supported Metal Phthalocyanines, 1. Bulk Polymerization in Relation to the Microcrystalline Structure of Supported Metal Phthalocyanines

Abstract

Different catalyst samples of nickel(II) and copper(II) phthalocyanines supported over bentonite clay (Indian type) were prepared with complex loadings ranging between 0.2 and 2.2 wt.‐%. Catalyst activities were investigated in the bulk polymerization of methyl methacrylate (MMA) at 80°C in the absence and in the presence of sodium bisulfite as a cocatalyst. In all cases, the catalyst efficiency was evaluated in terms of conversion yield (%), polydispersity index (M̄w/M̄n) was determined via GPC analysis in toluene. The stereotacticity was determined from 1H NMR spectra. Optimum polymerization conditions were determined for both catalyst systems. Samples with metal phthalocyanines loadings of 1.8% were the most active ones. The polymers produced have controlled molecular weights, which are nearly proportional to conversion, show narrow molecular weight distributions and syndiotactic‐rich steric structures. Nickel phthalocyanine seemed to have more stereoregulating effect while copper phthalocyanine had a more enhancing effect for the living polymerization process. The microstructure of solid catalysts was investigated by means of scanning electron microscopy and were correlated with activity data.

Catalytic Behavior of Cobalt (II) Phthalocyanine Immobilized on Bentonite Clay in Bulk Polymerization of Methyl Methacrylate

“…These findings run in agreement with those observed using NiPc and CuPc=bentonite systems [18]. For the samples of 0.2 wt% and 2.2 wt% loadings, the discrepancy mentioned in b values is shown to be linked with the presence of higher % of isotacticity; the samples behaving almost as the bare bentonite clay [19].…”

“…The catalytic activity of various samples was measured in the bulk polymerization of methyl methacrylate [18]. For this purpose, the freshly distilled stabilizer-free monomer (2.8 g) was introduced into the polymerization tube (20 ml capacity) together with a weighed sample of the catalyst (0.06 g) of different complex loadings (concentration of which varied between 7.5 Â 10 À6 and 82.5 Â 10 À6 mol% CoPc with respect to the monomer).…”

“…The pure complex or its ligand shows almost an inhibiting effect to the polymerization process. The same observation has been reported for pure Ni (II) and Cu (II) phthalocynine [18]. The dimerization of CoPc molecules seems to be responsible for the lack of activity as reported for some other reactions [6,7].…”

“…Close data were obtained previously in the presence of AIBN [23], CCl 4 =Ru(II) [24] as well as with NiPc and CuPc systems [18], which were accepted to produce polymers via higher contribution of free radical initiation.…”

Various Characteristics of Nanosized V2O5/TiO2and MoO3–Modified V2O5/TiO2Catalytic Systems Used in Redox-Initiated Polymerization of Methyl Methacrylate

“…On the other hand, the polymerization of methyl methacrylate (MMA) has been studied in the presence of some metal oxides and complexes [e.g., [14][15][16][17][18][19][20]. For example, in our previous investigation [14], supported NiO=bentonite clay was found to catalyze the polymerization process anionically, as ions enhanced by nitrite remained in narrower pores of the catalyst system, through decomposition of nickel precursor.…”