In situ reinforced poly(ether ether ketone) nanocomposites by covalently modified multiwalled carbon nanotubes via surface‐grafting polymerization

Covalent modification of multiwalled carbon nanotubes (MWCNTs) is an efficient way to improve the interfacial interaction and compatibility between MWCNTs and the matrix. In this article, MWNCTs were covalently modified by 4,4′‐difluorobenzophenone (DB) to allow temperature‐tolerant functional groups on the walls. These surface‐functionalized MWCNTs (MWCNTs‐DB) were then attached to poly(ether ether ketone) (PEEK) resins by in situ grafting polymerization, to prepare high‐strength PEEK nanocomposites. The addition of 1 wt% MWCNTs‐DB improved the tensile and flexural strength of the PEEK nanocomposite by 28% and 22%, respectively, compared with pristine PEEK. In particular, the optimal break at strain of the PEEK nanocomposites reaches 39%. The glass transition temperature of the PEEK nanocomposites increased from 148 to 153°C, indicating strong interfacial interactions between MWNCTs and PEEK. Furthermore, scanning electron microscopy images confirmed the amelioration of MWNCTs dispersion in PEEK resins achieved by in situ grafting polymerization. Our results demonstrate the potential of surface‐functionalized carbon nanotubes for use in high‐temperature applications and offer innovative protocols for designing and preparing high‐performance nanocomposites with enhanced mechanical properties, which could have applications in various fields such as aerospace, automotive, and biomedical engineering. Covalent modification of multiwalled carbon nanotubes (MWCNTs‐DB) and in situ grafting polymerization was used to prepare high‐strength PEEK nanocomposites.The addition of 1 wt% MWCNTs‐DB improved the tensile and flexural strength of the PEEK nanocomposite by 28% and 22%, respectively, compared with pristine PEEK.