TY  - JOUR
AU  - Brémaud, I.
AU  - Ruelle, J.
AU  - Thibaut, A.
AU  - Thibaut, B.
PY  - 2013//
TI  - Changes in viscoelastic vibrational properties between compression and normal wood: Roles of microfibril angle and of lignin
JO  - Holzforschung
SP  - 75
EP  - 85
VL  - 67
IS  - 1
KW  - Compression wood (CW)
KW  - Damping coefficient
KW  - Ft-Ir
KW  - Internal friction
KW  - Lignin
KW  - Microfibril angle (MFA)
KW  - Picea abies
KW  - Pinus pinaster
KW  - Pinus sylvestris
KW  - Specific dynamic modulus of elasticity
KW  - Viscoelastic vibrational properties
N2  - This study aims at better understanding the respective influences of specific gravity (γ ), microfibril angle (MFA), and cell wall matrix polymers on viscoelastic vibrational properties of wood in the axial direction. The wide variations of properties between normal wood (NW) and compression wood (CW) are in focus. Three young bent trees (Picea abies, Pinus sylvestris and Pinus pinaster ), which recovered verticality, were sampled. Several observed differences between NW and CW were highly significant in terms of anatomical, physical (γ, shrinkage, CIE Lab colorimetry), mechanical (compressive strength), and vibrational properties. The specific dynamic modulus of elasticity (E′/γ) decreases with increasing MFA, and Young's modulus (E′) can be satisfactorily explained by γ and MFA. Apparently, the type of the cell wall polymer matrix is not influential in this regard. The damping coefficient (tan δ) does not depend solely on the MFA of NW and CW. The tanδ-E′/γ relationship evidences that, at equivalent E′/γ, the tan δ of CW is approximately 34% lower than that of NW. This observation is ascribed to the more condensed nature of CW lignins, and this is discussed in the context of previous findings in other hygrothermal and time/frequency domains. It is proposed that the lignin structure and the amount and type of extractives, which are both different in various species, are partly responsible for taxonomy-related damping characteristics. Copyright © by Walter de Gruyter • Berlin • Boston.
UR  - http://dx.doi.org/10.1515/hf-2011-0186
N1  - Export Date: 25 February 2013; Source: Scopus
ID  - Bremaud_etal2013
ER  -