Ɛ-Caprolactone and Tetrahydrofuran Copolymerization with a Green Acid Activated Montmorillonite Catalyst: Reaction Optimization with the Taguchi Method

In this study, poly (ɛ-Caprolactone-co-Tetrahydrofuran) copolymer was synthesized using a green solid acid catalyst prepared with Montmorillonite clay (MMT). The prepared nanocatalyst was characterized by X-Ray Diffraction (XRD) analysis. The synthesized copolymer was investigated with Fourier Transform InfraRed (FT-IR), Hydrogen Nuclear Magnetic Resonance (HNMR), Gel permeation Chromatography (GPC), and Differential Scanning Calorimetry (DSC) analysis. Tg of the synthesized copolymer was found to be 28.91 °C. The highest average molecular weight (Mn) was calculated at about 2366 at 65 °C and 24 h of reaction time. The PDI data extracted showed a narrow PolyDispersity Index (PDI) of the synthesized copolymers.  The reaction conditions were optimized with the Taguchi method and Design of Experiments (DOE). 10%wt of nanocatalyst amount, 65 °C of reaction temperature, 24 h of reaction time, and Toluene as solvent were found to be optimum levels for the reaction. Up to 64% of the yield was obtained for copolymerization. Different factor interactions were studied with ANOVA interaction plots. Taguchi analysis results were in agreement with GPC results. The prepared nanocatalyst was recovered and its reusability for three cycles was approved.