Transamidation between PA1012 and PA612 was investigated with combination techniques including differential scanning calorimetry (DSC), rheometry, nuclear magnetic resonance (NMR) and variable-temperature Fourier transform infrared spectroscopy (VT-FTIR). Based on the increase of storage modulus with sweep time, the presence of reactive chain ends were proved, promoting chain growth in either polyamide and interchange reaction in binary blend at high temperature. NMR and VT-FTIR testing signals sufficiently convinced the expected interchange reaction. Quantitative data analysis of DSC and NMR provided direct evidences for evaluating the exchange degree. Various experimental parameters were systematically considered, including reaction temperature and time, blending composition and categories of polyamides. Raising the reaction temperature or prolonging the reaction time would accelerate the transamidation rate and degree. The interfacial miscibility between two LCPA components could be improved by the formation of copolyamides. This work provides a quantitative evaluating method to detect the transamidation extent between two aliphatic LCPAs that overcomes the traditional characterization limitation which is only feasible for whose polyamide component chain is with large volume structure like benzene ring. (C) 2014 Elsevier Ltd. All rights reserved.