Copolymers (polyoxymethylene) were prepared by cationic copolymerization of 1,3,5-trioxane (TOX) with 1,3-dioxolane (DOX) in the presence of Maghnite-H+ (Mag-H+) in solution. Maghnite is a Montmorillonite sheet silicate clay, with exchanged protons to produce Mag-H+. Various techniques, including H-1-NMR, C-13-NMR, FT-IR spectroscopy, and Ubbelohde viscometer were used to elucidate structural characteristics properties of the resulting copolymers. The influence of the amount of catalyst, of dioxolane (DOX), temperature, solvent, and time of copolymerization on yield and on intrinsic viscosity of copolymers was studied. The yield of copolymerization depends on the amount of Mag-H+ used and the reaction time. We also propose mechanisms involved in the synthesis of copolymer (polyoxymethylene). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2820-2827, 2010