Plasma treatment and annealing conditions on mechanical and electrical properties of <scp>thermoplastic</scp> composites

Abstract In this research carbon fibers (CFs) with plasma polyethylene (PPE) was utilized for enhancing the properties. The 10 wt% CF with PPE (CF/PPE) exhibited favorable electrical conductivity (34 Ω cm), with better tensile strength (22.7 MPa), flexural strength (26.89 MPa) compared with the other CF combinations. In the positive temperature coefficient (PTC) test, after the initial trial, the CF/PPE combination exhibited a change in path at higher temperatures (125 and 128°C) due to temperature fluctuations, which altered the properties of composites. It is evident that the resistivity (R) ratio exhibits higher values (CF/PPE) for annealing samples (90°C for 5 h). The annealing process resulted in a PTC intensity of 2.53, which was higher than nonannealing (1.94). Scanning electron microscopy (SEM) analysis without annealing procedure revealed a greater number of deformations in the combination, which resulted in decrease in repeatability. The majority of combinations exhibited enthalpy of melting between 114.3 and 116.4 J/g. The annealed combination, which was heated to 128°C, exhibited an increase in enthalpy up to 122.4 J/g. The melting point of both the annealing and nonannealing samples increased from 131 to 134.1°C following the R–T test, while the crystallization temperature remained unaffected.