Analysis of Heat-Treated Taurus Cedar (Cedrus libani) Wood Surface Properties with Fourier Transform Infrared (FTIR) Spectroscopy and Contact Angle Measurement

This study examined the changes in the chemical properties of heat-treated cedar (Cedrus libani) wood as a function of four different treatment temperatures (120, 150, 180 and 210 °C) and three different treatment durations (2, 5 and 8 hours). Particular emphasis was placed on the changes observed in the 1740 cm-1 carbonyl absorption band in the FTIR spectra of the esterification reaction products, which occurred at 120, 180 and 210 °C for 2, 5 and 8 hours. Surface energies of the samples were also calculated using Young’s equation and contact angle measurements with three different liquids: water, glycerol, and hexane. Subsequently, the surface free energies were analyzed using the Lifshitz-van der Waals/acid-base (LW-AB) approach. FTIR analysis indicated that esterification reactions occurred more intensely at temperatures between 180 °C and 210 °C. Contact angle measurements revealed a decrease in polarity and a corresponding increase in non-polarity with increasing heat treatment temperature and duration. Free surface energy analysis demonstrated an increase in the LW component in cedar wood samples treated at 120, 180 and 210 °C for all treatment durations (2, 5 and 8 hours), indicating that surface modification had occurred. These results suggest an increase in nonpolar effects within the surface energy components of the samples, resulting in increased hydrophobicity.