Correlation of the structure of clay filled polyurethane with surface properties

The surface properties of rectorite (REC) directly affect the dispersion of rectorite in the polymer matrix and make a great contribution to the structure and mechanical properties of composite materials. The inverse gas chromatography (IGC) was used to investigate the dispersive component of the surface energy (γ_ad)and the surface acid-base properties of the native rectorite, organic-modified rectorite with dodecyl benzyl dimethyl ammonium bromide (12-OREC), organic-modified rectorite with hexadecyl trimetbyl ammonium bromide (16-OREC) and thermoplastic polyurethane (TPU) with non-polar and polar probes. The correlation of the surface properties of REC and TPU with the structure of the composites was analyzed. The results indicate that the modification of REC lowers its surface energy and changes the surface from being acidic to being predominantly basic and hence improving the dispersibility of 12-OREC and 16-OREC in TPU; 12-OREC can achieve the best dispersibility in TPU, because the dispersive energy and acid-base property are most comparable with those of the polymer matrix.