A new approach for the polymerization of tetraphenyltetramethylcyclotetrasiloxane by an environmentally friendly catalyst called Maghnite-H+

Abstract

This work is devoted to the study of the cationic ring opening polymerization of tetraphenyltetramethylcyclotetrasiloxane (D4Ph,Me), using a solid green catalyst prepared by the activation of a natural clay by sulfuric acid (Maghnite-H+). This treatment leads to the spacing of the montmorillonite sheets due to the substitution of the existing interlayer cations by the protons of the acid. This consequence is clearly shown on the X-ray diffraction (XRD) spectrum. The polymerization reaction proceeded in bulk and under mild conditions. Various tests were carried out by changing the temperature, the time and the catalyst mass content in order to increase, at the same time, the yield of the reaction and the average molecular mass of the polyphenylmethylsiloxane (PPMS) obtained. The structure of the PPMS obtained was identified by infrared (IR), 1H nuclear magnetic resonance (NMR) and 13C NMR analyses over different periods of time. The thermal behavior was investigated by differential scanning calorimetry (DSC) analysis. At the end, in order to show the role played by the Maghnite-H+ during the various reaction stages, a reaction mechanism was proposed.

Recent advances in green cationic polymerization

“…This non-toxic cation initiator has emerged as an efficient initiator for olefin monomer polymerization, offering a promising alternative to heavy metal-containing initiators (such as SnCl 4 , AlCl 3 , TiCl 4 , etc). [56][57][58][59][60][61] In 2011, Malika Chabani utilized Maghnite-H + as a initiator for bulk cationic polymerization of 2-chloroethyl vinyl ether (CEVE). 62 The study found that the polymerization in dichloromethane or toluene solution yielded higher molecular weight and narrower molecular weight distribution (MWD) (Figure 5).…”

“…The separated Maghnite‐H + initiator can be recycled and reused. This non‐toxic cation initiator has emerged as an efficient initiator for olefin monomer polymerization, offering a promising alternative to heavy metal‐containing initiators (such as SnCl 4 , AlCl 3 , TiCl 4 , etc) 56–61 …”

Green synthesis, anionic polymerization of 1,4-bis(methacryloyl)piperazine using Algerian clay as catalyst

“…Maghnite has acid sites of Brönsted and Lewis type. These active sites responsible for priming chemical reactions can be created by binding high charge density cations such as protons on the surface of layers [18][19][20]. Proton-loaded maghnite has been successfully used as a heterogeneous catalyst for many polymerization reactions [21][22][23].…”

Highly Conductive and Soluble Polymer Synthesized by Copolymerization of Thiophene with Para-Methoxybenzaldehyde Using Clay Catalyst

“…The chemical and physical properties of the mineral clay depend strongly on the amount of water present between the layers. Clay minerals have catalytic properties in the polymerization reactions of several cyclic and siloxane monomers due of the surface acidity, which have been the subject of huge number of studies [10][11][12][13][14][15][16].…”