Formation and stability of the conducting cluster in the composite filaments based on polylactide and carbon nanofibers

Abstract Composite threads based on polylactide (PLA) containing up to 20 wt% carbon nanofibers (CNF) were produced using melt technology. The formation of a percolation cluster was studied in composite filaments with various morphologies (non‐oriented, subjected to isothermal crystallization, and oriented by six times). By adding 20 wt% CNF, a specific resistance of 10⁰ Ohm m was achieved in the PLA filament. With orientation stretching, the specific resistance was 10⁷ Ohm m, regardless of the CNF concentration. The scanning electron microscopy study showed poor adhesion between PLA and CNF. Threads containing 1 wt% CNF demonstrated stable conductive characteristics under dynamic loading for 24 h (50% of their breaking load). Studies of the creep of composite fibers have shown that small amounts of CNFs promote the sliding of polymer fibrils. In vivo tests showed that the addition of 5 wt% CNF led to an increase in the rate of bioresorption of PLA filaments. Additionally, the conductive properties were maintained for 12 months after implantation. The prepared filaments can be used in flexible electronics for biomedical applications.