The structural and rheological properties of synthetic talc/polyamide (ST/PA) composites, elaborated by simultaneous melt mixing of a PA6 or PAl2 matrix and a hydrogel filled with talc, were studied, focusing on the difference between PA6 and PAl2 based nanocomposites. The structure of ST/PA composites is shown to be largely composed of nanometric particles. However, the presence of few micrometric aggregates is shown at moderate solid volume fractions, for both PA6 and PAl2. The results also show that PA6 matrix is more efficient than PAl2 matrix to disperse synthetic talc nanoparticles; the difference in matrix effect is discussed in terms of matrix polarity, PA chain radius of gyration and role played by water brought by the hydrogel. Finally, the results of the present study suggest that the structural and rheological properties of ST/PA are close to those of organically modified montmorillonite/PA nanocomposites, especially when PA6 is the matrix. (C) 2015 Elsevier Ltd. All rights reserved.