Maghnite‐H⁺, a solid catalyst for the cationic polymerization of α‐methylstyrene

Abstract

The polymerization of a-methylstyrene (AMS) catalyzed by Maghnite-H 1 (Mag-H) was investigated. Mag-H is a montmorillonite sheet silicate clay, exchanged with protons. It was found that the cationic polymerization of AMS is initiated by Mag-H at ambient temperature in bulk and in solution. The effect of the amount of Mag-H, the temperature, and the solvent was studied. The polymerization rate increased with increase in the temperature and the proportion of catalyst, and it was larger in nonpolar solvents. These results indicated the cationic nature of the polymerization. It may be suggested that the polymerization is initiated by proton addition to monomer from Mag-H.

A Renaissance in Living Cationic Polymerization

“…The M w values of the obtained polymers were similar, while the MWDs of the products were much narrower in solutions ( M w / M n < 1.2) than in bulk ( M w / M n = 4.2−4.6) . H-Maghnite was also shown to catalyze ring-opening polymerization of THF, ε-caprolactone, − and oxetanes , and polymerization of α-methylstyrene . Interestingly, this catalyst produced poly(α-methylstyrene) with higher molecular weight above 0 °C, whereas only oligomers were obtained with metal halides .…”

“…148 H-Maghnite was also shown to catalyze ring-opening polymerization of THF, 149 ε-caprolactone, [150][151][152] and oxetanes 153,154 and polymerization of R-methylstyrene. 155 Interestingly, this catalyst produced poly(R-methylstyrene) with higher molecular weight above 0 °C, whereas only oligomers were obtained with metal halides. 156 Furthermore, the resulting polymers had narrow MWDs (M w /M n ∼ 1.2).…”

“…Interestingly, this catalyst produced poly(α-methylstyrene) with higher molecular weight above 0 °C, whereas only oligomers were obtained with metal halides . Furthermore, the resulting polymers had narrow MWDs ( M w / M n ∼ 1.2) . Heteropoly acid salts, M 0.5 H 0.5 PW 12 O 40 (M = Cs, NH 4 ), were also found to be active catalysts for the IB polymerization and gave PIB with high terminal vinylidene content (75−80%) and large polydispersity, which is claimed good for dispersants .…”

Polymerization of DL-Lactide induced by Protonated Montmorillonite clay as a solid catalyst: Mechanism study

“…The spectra provide information about the local environment of the aluminum sites in Maghnite, two small bands of two tetra-coordinated AlO 4 (Al TD1 and AL Td2 ) at 58-60 ppm and 68-71 ppm, and another signal at 3-4 ppm attributed to octahedral AlO 6 (Al Oh ) 25 . AlO 4 sites in the maghnite structure are the consequence of isomorphic ions substitution within the silicate layers 10,[15][16][17] . Meanwhile, the 27 Al NMR spectra of Maghnite-H + and of Maghnite-H + /Polymer mixture after the reaction were closely identical, two very significant differences were observed in the 27 Al NMR spectra.…”

“…In our previous works, we have already reported about polymerization reactions catalyzed by Maghnite-H + , a proton exchanged montmorillonite clay. This new non-toxic available eco-catalyst exhibited higher efficiency via the cationic polymerization of vinylic and hetero-cyclic monomers [10][11][12][13][14][15][16][17][18] . The aim of this study is to elucidate the interactions between the monomer (D, L-Lactide) and the inorganic platelets of Maghnite occurring upon the reaction of polymerization.…”