moisture repellent effect of acetylation on poplar fibers

fibers of poplar wood (populus nigra l.) were prepared and oven dried. afterwards, they were acetylated with acetic anhydride without a catalyst. acetylation was carried out for different durations at 120ºc. different weight percentage gains (wpgs) were achieved based on the operating conditions. acetylated fibers were exposed to varying levels of relative humidity to determine equilibrium moisture contents (emc). ir-spectra were also taken from the fibers to indicate substitution of the hydroxyl groups by the acetyl groups. results showed that the acetylation decreased moisture absorption in the fibers. it was revealed that a wpg of about 10% had a proper moisture repellent effect on fibers. ir-spectra confirmed fully the substitution of the acetyl groups.