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

Abstract

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.

Fabrication of robust polyamide 6 with local cross‐linked structure via dynamic vulcanization

“…Toughening modification of PA6 has always been a research hotspot because PA6 is sensitive to notch, which leads to low impact strength. To enhance its toughness, the utilization of tougheners is a common and effective method, such as core‐shell particles, 7–10 rubbers, 11–14 and thermoplastic elastomers, 15–17 but the rigidity of modified PA6 is prone to be compromised. For example, with the addition of polyolefin elastomer‐graft‐maleic anhydride (POE‐MAH), the modified PA6 showed a nearly 11‐fold increase in impact strength compared to the original PA6, meanwhile, the yield stress dropped by nearly 50% 18 .…”