Synthesis and Characterization of Polyurethane/Mg-Al Layered Double Hydroxide Nanocomposites

Layered double hydroxide (LDH) is a new type of nanofiller, which improves the physicochemical properties of the polymer matrix. In this Study, 1, 3, 5, and 8 wt% of dodecyl sulfate-intercalated LDH (DS-LDH) has been used as nanofiller to prepare a series of thermoplastic polyurethane (PU) nanocomposites by solution intercalation method. PU/DS-LDH composites so formed have been characterized by X-ray diffraction and transmission electron microscopy analysis which show that the DS-LDH layers are exfoliated at lower filler (1 and 3 wt%) loading followed by intercalation at higher filler (8 wt%) loading. Mechanical properties of the nanocomposite with 3 wt% of DS-LDH content shows 67% improvement in tensile strength compared to pristine PU, which has been correlated in terms of fracture behavior of the nanocomposites using scanning electron microscope analysis. Thermogravimetric analysis shows that the thermal stability of the nanocomposite with 3 wt% DS-LDH content is approximate to 29 degrees C higher than neat PU. Limiting oxygen index of the nanocomposites is also improved from 19 to 23% in neat PU and PU/8 wt% DS-LDH nanocomposites, respectively. (C) 2009 Wiley Periodicals, Inc. J AppI Polym Sci 114: 2691-2699, 2009