S.-T. Chang, H.-T. Chang, Y.-S. Huang, F.-L. Hsu
Effects of Chemical Modification Reagents on Acoustic Properties of Wood
Summary
The acoustic properties of several chemically modified Sitka spruce samples (Picea sitchensis Carr.)
were evaluated in the longitudinal direction of wood specimens. Sitka spruce treated with glyoxal and
carboxymethyl cellulose (CMC) displayed superior acoustic properties to those obtained by the other
treatments. The acoustic converting efficiency (ACE) of the glyoxal-CMC treated Sitka spruce was 1.84
times of that of the untreated specimen and the specific dynamic Young's modulus (E?/r) was retained
without decrement after such treatment. Changes in the tan? of Sitka spruce treated with glyoxal and different
concentrations of 1,4-butanediol were opposite. With a low concentration of 1,4-butanediol
(10%), the tan? of the treated specimen decreased as a result of the formation of crosslinked cyclic structures.
The potential presence of more alkyl hydroxyl groups in the Sitka spruce, after being treated with
glyoxal and a high concentration of 1,4-butanediol (20%), resulted in the increment of tan? and the
decrement of ACE. The impairment of the acoustic properties of Sitka spruce was caused by the introduction
of free chains with endwise carboxylic acid groups into cell walls after the succinic anhydride
treatment. Slight improvement on the ACE of Sitka spruce was achieved by the reaction with acetic anhydride
and the decrease in the tan? was about 15%, which was attributed to the partial formation of
crosslinked matrix. These results revealed the improvement of the acoustic properties of chemically
modified wood that was probably achieved only by the formation of network structures between wood
components and reagents.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 54, 10/2000
Pages: 669 - 675
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