Synthesis and characterization of novel segmented polyurethane/clay nanocomposites

A novel segmented polyurethane(Pu)/clay nanocomposite has been synthesized by polyurethane and organoclay. 12 aminolauric acid (12COOH) and benzidine (BZD) were used as swelling agents to treat Na+-montmorillonite and for for ming organoclay (12COOH-mont acid BZD-mont) through ion exchange. The nanom eter-scale silicate layers of organoclay were completely exfoliated in PU i n the cases of 1, 3 and 5% 12COOH-mont/PU and in the cases of 1 and 3% BZD- mont/PU nanocomposites as confirmed by X-ray diffraction pattern and transm ission electron microscopy studies. The segmented structures of PU were not interfered by the presence of the silicate layers in these nanocomposites as evidenced by their glass transition and degree of phase separation from differential scanning calorimetry and Fourier transform infrared measuremen ts. A two-fold increase in the tensile strength and a three-fold increase i n the elongation were found for 1% BZD-mont/PU as compared to that of pure PU. Additionally, both 1% 12COOH-mont/PU and 1% BZD-mont/PU exhibited lower water absorption properties than that of pure PU. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.