A series of polymeric composites have been prepared using layered particulate components like nano-clays or plate-shaped, for example kaolin, mica and aluminium hydroxides. These components have been added to the polymeric matrix to obtain required heat resistance, high modulus and some others physical and mechanical properties. However, the macroscopic properties of such composites heavily depend on the dispersion of the added particles in the polymer matrix. In order to improve this dispersion, modified nanofillers are used and special processing routes are employed.
In the present study boehmite modified by exposure to lactic acid were used. Unmodified and modified boehmite particles were introduced into a polyurethane matrix by in situ polymerisation. The fillers were added to the polyurethane matrix in 0.5 and 3.5% wt. Components used for PUR nanocomposites synthesis were: polyester diol (PEA) with MW=2000, 4,4'diphenylmethane diisocyanate (MDI), mixture of chains extenders (DIOL A, DIOL B) and modified boehmite. The synthesis was performed in one-shot technique. Polyurethanes composed of PED:MDI:DIOL A: DIOL B with molar ratio 6:9:2:1 were synthesized.
The characterization of the nanocomposites has been carried out using atomic force and high resolution scanning microscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It has been found that by using boehmite modified with lactic acid, nano-composites with high degree of dispersion of the nano-filler can be obtained via mechanical stirring alone.
The analysis of the microstructure images obtained with that microscopic techniques make it possible to explain properties of fabricated nano-composites properties in terms of their relationships with microstructure characteristics.
The study was financially supported by Polish Committee for Scientific Research PBZ-KBN-095/T08/2003.