The structure and thermal properties of novel polyurethane/organoclay nanocomposites obtained by pre-polymerization

All aliphatic polycarbonate-based polyurethanes (PC-PUs) and their layered-silicate nanocomposites were synthesized by pre-polymerization procedure. Hard domains of materials prepared in the form of films consist of hexamethylene-diisocyanate and 1,4-butane diol (chain extender). Two polycarbonate diols differing in chain constitution were used as soft segments. The ratio (R) of OH groups belonging to the diol and the chain extender, as well as hard segment content (HS) was kept constant (R = 1 and HS = 30 wt.%). For nanocomposites preparation, organically modified montmorillonite and bentonite were used (1 wt.%). FTIR was performed to investigate hydrogen bonding formation and degree of phase separation. The micro-phase structure of obtained polyurethanes was studied using SAXS. The influence of morphology and phase behavior of prepared elastomers was estimated combining WAXD and DSC. Thermal properties of PC-PU hybrid materials are found to be influenced by dispersion of nanofillers with layered structure.