Abstract: As a new high-exhaustion chrome tanning auxiliary, the amino-terminated hyper-branched polyamide (HBPN) was used in the chrome tanning process of pickled pig hide, and its effect was investigated on the chrome absorptivity, shrinkage temperature (T_s), denaturation temperature (T_d) and thermal degradation active energy (E) of the resulting wet blue, in which the traditional chrome tanning was used as the blank control. Results showed that the addition of 1% HBPN (based on the weight of pickled pig hide) could significantly increase chrome absorptivity to 83.58%, which is 31.7% higher than that of the blank control. At the same time, the Ts, Td and denaturation enthalpy of the obtained wet blue were improved from 97.4 ℃ to 105.9 ℃, 112.47 ℃ to 116.63 ℃ and 129.2 J/g to 222.7 J/g, respectively. The calculatedE values were 169.524-196.668 kJ/mol by Flynn-Wall-Ozawa method and 153.314 kJ/ mol by Kissinger method, respectively, which are higher than 147.244 kJ/mol for the blankcontrol. These results confirm that the use of HBPN in chrome tanning processcan improve thechrome absorptivity and the hydrothermal stability of wet blue, indicating its great application potential as a high-exhaustion chrome tanning auxiliary.

Key words: hyper-branched polyamide, high-exhaustion chrome tanning auxiliary, chrome absorptivity, wet blue, hydrothermal stability, pyrolysisactivation energy