The carbon fibers have been exposed to nitric acid oxidation treatments and introduced into polyoxymethylene composites (POM/CF). The nitric acid treatment increases the number of the flaws, roughness of the surface, and disorder of carbon atoms on fiber, as well as introduces reactive functional groups, which could lead to a better mechanical bonding between fiber and the matrix. It is shown that the impact strength and fiber-matrix adhesion in composites (POM/mCF) are superior to those for POM/CF composites. Simultaneously, the addition of mCF improves flexural strength and modulus relative to virgin POM significantly. Average friction coefficient values of POM/CF composites are lower than that of POM/mCF composites. As the percentage of fiber increases, the trend of wear ratio of the composites goes down initially and bumps up afterwards. The results indicate that the proper contents of CF and mCF in composites range from 5 wt % to 20 wt %. Scanning electron microscopy of worn surface morphology has revealed that the main wear mechanism of the composites were adhesive wear and ploughing wear. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41812.

Sorption and desorption of carbon dioxide (CO₂) in polycarbonate (PC) with different dimensions were systematically investigated at temperatures of 40, 60, and 80°C; pressures ranged from 7 to 20 MPa; and soaking time ranged from 0.5 to 4 h. The experimental data were analyzed by a mass-loss analysis. With the assumption of Fickian diffusion, the sorption amount and the sorption diffusivities (D_s) under supercritical conditions, and desorption diffusivities (D_d) under ambient temperature and pressure were determined. The crossover of the sorption isotherms was presented, which indicated that the change of mass transfer mechanism had occurred. It was found that D_s increased with temperature, whereas D_d showed a contrary trend. Moreover, the linear relationship between sorption amount and specific surface area was also observed, which suggested that the specific surface area was one of the important factors on the sorption amount for thick samples in swelling process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008