Grafting of an aminated poly(phenylene sulphide) derivative to functionalized single-walled carbon nanotubes

Abstract

An aminated poly(phenylene sulphide) derivative (PPS-NH 2) has been covalently anchored to the surface of epoxy and acid-functionalized single-walled carbon nanotubes (SWCNTs). The characterisation through Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis and Kaiser test corroborated the success of the grafting reactions, and allowed the identification and quantification of the covalent moieties. Scanning and transmission electron microscopy indicated an increase in the bundle diameter of the SWCNTs upon anchoring of the polymer chains. The results showed that the storage modulus, glass transition temperature and electrical conductivity of the polymer were exceptionally enhanced by the attachment to the SWCNTs. In contrast, the crystallization and melting temperature, degree of crystallinity and crystal size considerably decreased, as revealed by differential scanning calorimetry and X-ray diffraction experiments, due to the inactive nucleating role of these SWCNTs and the intense restrictions on chain mobility imposed by the SWCNT–polymer interactions. Acid-functionalized SWCNTs were more effective for reinforcing PPS-NH 2 than epoxy-functionalized SWCNTs, attributed to the formation of a larger number of covalent bonds, albeit led to a smaller increase in the electrical conductivity of the polymer. The results herein offer useful insights into the development of multifunctional CNT-reinforced thermoplastic composites for a wide variety of applications.