[The interaction between La and polyurethane system].

A series of polyether polyurethane (PU)-LaCl3 composites with different lanthanum contents were prepared. DSC results indicate that LaCl3 promotes phase transition behavior of the LaCl3/PU composites, which causes the endothermic peak at 11.58 degrees C to disappear. FTIR spectroscopy demonstrates that significant variation can be observed. The peak at 1633 cm(-1) attributed to carbonyl vibration and the peak at 3311 cm(-1) attributed to N-H stretching band moves to 1647 cm(-1) and 3355 cm(-1), respectively, when LaCl3 is introduced into the PU system. A new band (-200 cm(-1)) assigned to the La-O band was observed, and the far IR result provided a direct evidence of the coordination between La3+ ion and C=O group of PU system.