Cationic Ring Opening polymerization of ε-caprolactam by a Montmorillonite Clay Catalyst

Abstract

The ring opening bulk polymerization of ε-caprolactam catalyzed by Maghnite-H + was reported. Maghnite-H + is a montmorillonite silicate sheet clay was prepared through a straight forward proton exchange process. The effect of the amount of catalyst, and temperature was studied. Increasing Maghnite-H + proportion and temperature produced the increase in ε-caprolactam conversion. The kinetics indicated that the polymerization rate is first order with respect to monomer concentration. Mechanism studies showed that monomer inserted into the growing chains with the acyl-oxygen bond scission rather than the break of alkyl-nitrogen bond.

Green Polymerization of Hexadecamethylcyclooctasiloxane Using an Algerian Proton Exchanged Clay Called Maghnite-H+

“…This result indicates that the Maghnite-H + can play the opposite role after periods of time sufficiently large. Similar results were previously obtained by several authors [34,35]. Moreover, the conversion of the monomer decreased when we used more than 4 % of the Maghnite H + , this is due to the existence of a large number of active sites carried on the surface of montmorillonite, which in turn began to attack the polymer chains in place of the monomer rings, resulting in the breaking of these chains and the formation of the oligomers.…”

Catalytic Activity of Maghnite-H+ in the Synthesis of Polyphenylmethylsiloxane under Mild and Solvent-free Conditions

“…This result indicates that the Maghnite-H + can play the opposite role after periods of time sufficiently large. Similar results were obtained in previous studies [7,8]. On the other hand, the average molecular mass increases with increasing reaction time, the maximum value for the different Maghnite-H + contents is about 150 min, then it stabilizes almost up to 180 min, so that it begins to decrease.…”

“…This catalyst was developed in Polymer Chemistry Laboratory «LCP», it has shown remarkable catalytic capabilities in polymerization reactions of various vinyl and heterocyclic monomers. Several studies have been carried out at the LCP concerning the introduction of Maghnite-H + in the initiation of polymerization reactions [6][7][8]. In other works, Maghnite has been used as an inorganic reinforcement and as an initiator at the same time in different reactions in order to synthesize nanocomposite materials [9][10][11].…”

Green Polymerization of 4-(Oxiran-2-ylmethyl)morpholine

“…Maghnite-H + is a naturally occurring catalyst with considerable advantages used in the polymerization of several heterocyclic and vinyl monomers [10][11][12][13][14][15].…”