FABRICATION AND CHARACTERIZATION OF CARBON NANOTUBE/CARBON FIBER/POLYCARBONATE MULTISCALE HYBRID COMPOSITES

摘要

Multiscale hybrid composites consisting of carbon nanotubes (CNTs), woven carbon fiber (CF), and polycarbonate (PC) were fabricated via solution processing to overcome the difficulty of controlling the melt viscosity of thermoplastic resins. The hybrid composites were fabricated in two steps: impregnation of PC solution into CF textile followed by hot pressing. Experimental studies were performed to identify the optimal conditions to maximize the degree of CNT dispersion in chloroform and fiber-resin interfacial adhesion via plasma treatment of CF surface. Characterization of CNT dispersion state, surface chemical composition and surface roughness of CF revealed the optimal dispersion time of 8 hours, and various plasma treatment conditions were applied at speeds of 2, 4, 6, 8 and 10 m/min to investigate the effects of plasma irradiation time. From the XPS results, carboxylic group on the CF surface increased from 16 to 30% (in terms of relative peak area) with decreasing plasma treatment speed. Surface roughness was measured using three-dimensional topography measurement, which revealed the arithmetic roughness (Ra) of CF surface increased from 135 to 254 nm with decreasing plasma treatment speed. Dynamic mechanical analysis performed on CNT/CF/PC composites under temperature ramp-frequency sweep mode showed the storage modulus and tan delta peak were maximum at 16 GHz and 0.35 (at a frequency of 1 Hz) for 2 m/min samples. The proposed processing method provides a viable, effective technique for manufacturing thermoplastic-matrix composites containing nano and fiber reinforcements, which would otherwise be difficult to perform in melt state.