Properties of Polyamide-Zirconia Nanocomposites Prepared From Sol-Gel Technique

Transparent nanocomposites were prepared by producing zirconia network in glassy polyamide matrix using sol-gel technique. Different amounts of tetra-propyl zirconate (TPZ) were added in polymer solution using anhydrous dimethylformamide as solvent. TPZ was hydrolyzed and condensed in situ in the matrix for the generation of inorganic networks using diethylamine. Thin and transparent films containing different proportions of zirconia were obtained by evaporating the solvent. Mechanical, dynamic mechanical thermal and morphological analyses of these films were carried out. An increase in tensile modulus was observed with the films containing zirconia contents up to 15 wt%, but the elongation at rupture was found to decrease sharply on further addition of zirconia. Toughness of the hybrid materials decreased with increased amount of zirconia. Dynamic mechanical thermal analysis (DMTA) performed on the samples indicates an increase in the glass transition temperature; 102 degrees C with pure polyamide to 132 degrees C with polyamide containing 15 wt% zirconia contents. The storage modulus was also found to increase with increase in zirconia proportion in the matrix. The decrease in the storage modulus of the hybrids with rise in temperature was observed to be much smaller as compared with that of pure polymer. Thermal decomposition temperatures of the hybrids were found in the range of 450-500 degrees C. The weights of the residues left at 700 degrees C were nearly proportional to the zirconia contents in the original hybrids. The morphological studies suggest a uniform dispersion of zirconia domains in the matrix. POLYM. COMPOS., 30:95-100, 2009. (C) 2008 society of Plastics Engineers