Cationic polymerization of poly(α-methylstyrene-block-isobutyl vinyl ether) using Maghnite-H+ clay (Algerian MMT) as catalyst

The synthesis of a new copolymer poly(α-methylstyrene-block-isobutyl vinyl ether) by cationic polymerization is reported. The polymerization was performed in bulk under suitable condition at temperature 0 °C. The copolymer was prepared by the reaction of alpha-methylstyrene (α-MS) with isobutyl vinyl ether (IBVE), in the presence of a natural Algerian montmorillonite clay modified by 0.05–1 M H2SO4, known as Maghnite-H+, as proton source, a non-toxic and an efficient catalyst for cationic polymerization of many vinylic and hetero-cyclic monomers. It was found that H2SO4 concentration allows controlling the chemical composition, the porous structure of the acid-activated clays, and their catalytic performance. The maximal yield of polymer is observed in the presence of Algerian MMT modified by 0.25 M H2SO4. Effects of α-MS/IBVE molar ratio, catalyst concentration, on yield and molecular weight of polymer were revealed in the presence of the most active sample. The structure of the products obtained is confirmed by 1H-NMR, 13C-NMR (nuclear magnetic resonance), Fourier transform infrared spectroscopy, differential scanning calorimetry, and gel-permeation chromatography, finally, a mechanism for the reaction was proposed.