Successive in situ synthesis of Ag/PA6 nanocomposites

Abstract

A novel approach to in situ synthesis of silver/polyamide 6 (Ag/PA6) nanocomposites is reported. The method included two steps: in situ preparation of silver nanoparticles (Ag NPs) in molten ε-caprolactam (CL), followed by polymerization of residual CL. The CL was used as reducing agent, protecting agent and solvent in the synthesis of Ag NPs, as well as precursor monomers of polyamide 6 in the subsequent polymerization. The formation of Ag NPs was verified by X-ray diffraction. Transmission electron microscopy (TEM) showed that the as-synthesized Ag NPs had a size less than 25 nm and was uniformly embedded in polyamide 6 matrix. Fourier transformed infrared spectrometry (FTIR) and ¹³C NMR indicated that pre-oxidation of CL had little effect on chemical structure of the polyamide molecules, except for a decrease of molecular weight. The variation in particle size and size distribution of Ag NPs complicated the thermal behaviors of resultant nanocomposites.