P. Larsson et R. Simonson, A STUDY OF STRENGTH, HARDNESS AND DEFORMATION OF ACETYLATED SCANDINAVIAN SOFTWOODS, Holz als Roh- und Werkstoff, 52(2), 1994, pp. 83-86
In this work, properties such as bending strength (expressed as modulu
s of rupture and modulus of elasticity), hardness, and deformation und
er cyclic relative humidity have been studied for acetylated Scandinav
ian pine and spruce. The acetylation was performed with a limited amou
nt of liquid acetic anhydride without addition of catalyst or organic
cosolvent. The weight gain due to acetylation was 19.1% for the pine s
amples. Two kinds of spruce samples were acetylated to 18.2% (narrow a
nnual rings) and 23.3% (broad annual rings), respectively. The results
indicated that only small changes in strength were obtained. For pine
, modulus of rupture decreased with about 6%, and increased with about
7% for spruce. The modulus of elasticity also decreased for pine but
increased for spruce. For practical applications, these properties can
be considered unaltered. Acetylated pine wood showed increased Brinel
l hardness. Acetylated spruce wood did not tend to deform as much as u
nmodified wood when exposed to moisture cycled between 40 and 90% rela
tive humidity.