Enhanced Compatibility, Morphology, and Low-Temperature Toughness of Polyamide 6/Poly(dimethylsiloxane)/Epoxidized Silicone Rubber Composites

Epoxidized silicone rubber with an epoxy content of 5% (ESR-5) was introduced to improve the compatibility of the polyamide 6 (PA6)/poly(dimethylsiloxane) (PDMS) composite. The effects of the ESR-5 on the molecular structure, interfacial morphology, and toughness and thermal properties of the PA6/PDMS composite were investigated using nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic thermomechanical analysis (DMA). The FT-IR spectra and torque rheological testing confirmed the reaction between the epoxy group of ESR-5 and the carboxyl group at the end of PA6. The AFM and SEM images confirmed that the ESR-5 altered the interfacial thickness and remarkably decreased the average size of the dispersed rubber particles, which enhanced the interfacial compatibility. At a rubber content of 20% by weight in PA6/PDMS composites, the optimum impact strength at −60 °C, which is 469% higher than pure PA6, was obtained with an ESR-5 content of 50% in rubber phase.