Abstract
Clay/polyurethane nanocomposite was synthesized from the polyol and polymeric 4,4' diphenylmethane diisocyanate (PMDI) modified with the clay by in-situ intercalation process. Silanol group of the clay and NCO group of the PMDI were reacted for 24 hours at 50°C. FT-IR analysis of the clay modified with the PMDI demonstrated that the NCO characteristic peak was observed in the clay after modification reaction with PMDI. From the results of FT-IR and X-ray of the polyurethane nanocomposite, it is suggested that the exfoliation of the clay layers may be due to the reaction of forming polyurethane between the clay modified with the PMDI and polyol. The flexural and tensile strength of the clay/polyurethane nanocomposite with the modified clay showed the maximum values at 3 wt % of the modified clay. The Tg of the nanocomposite decreases with an increase in the modified clay. We suggest that the decrease in the Tg of the clay/polyurethane nanocomposite with the modified clay content may be due to an increase in the chain flexibility of the polyurethane backbone.
