Abstract:

The thermal decomposition process of water-solublity blocked isophorone diisocyanate (IPDI) was studied using thermal gravimetric analysis (TGA). The characteristic peaks of isocyanante groups at 40 and 140 ℃ were observed by Fourier transform infrared spectroscopy (FTIR). Results from TGA and FTIR showed that the degradation stage was a deblocking reaction of the blocked adduct. The Friedman-Reich-Levi (FRL) and Flynn-Wall-Ozawa (FWO) models were employed to investigate the apparent activation energies which were 125.0 and 124.5 kJ·mol-1, respectively. Based on the double equal-double step method, the reaction was analyzed by the apparent mechanism of the process of deblocking according to the Jander equation, which indicated that the reactive mechanism was a three-dimensional diffusion. The reaction order (n) and the logarithm of pre-exponential factor (lnA) were also determined using the FWO equation.

Key words: Dynamics, Blocked isocyanate monomer, Deblocking, Thermal stability