The development of anatomical, hydraulic and biomechanical properties in Scots pine (Pinus sylvestris L.) stems aged 7 to 59 years was followed. The hydraulic diameter and length of tracheids increased with age to a maximum at 15 and 35 years, respectively. Number of tracheids per unit of sapwood area decreased with age to a minimum of 500-600 tracheids mm(-2). Variations in specific hydraulic conductivity and Young's modulus of stems were associated with variation in anatomical properties. Over the time sequence considered, hydraulic and mechanical properties were positively related to each other and followed a similar developmental pattern, with no suggestion of a trade-off between the two. For most of the tree's life-cycle, heartwood made only a small contribution to whole-section mechanical stiffness because of its location close to the flexural neutral axis, and because of the presence of juvenile wood.
Some oligo-or polyamides containing several hydroxyl groups were synthesized in order to obtain new water-soluble compounds with a high affinity for polar materials as wood, paper, and natural fibers. The interest for the synthetic procedures is the use of renewable sources as starting compounds. In fact natural compounds or their derivatives, as L-tartaric acid, D(þ)-glucaric acid and a,a-trehaluronic acid, were used as dicarboxylic acids in the polycondensation reactions, in order to obtain several functionalized oligoamides. All the compounds obtained in this study were characterized through FTIR and NMR spectroscopy. The oligoamides, water-soluble and not provided with high-molecular weights, were tested as wood consolidants. Physical properties like hygroscopicity of stabilized wood, volume shrinkage, density, and basic density were evaluated on the treated samples and compared with those obtained in the same conditions for an untreated archeological sample and a recent wood sample.
Solid-state nuclear magnetic resonance (NMR) spectroscopic analysis were carried out on recent and archaeological wood. Cross-polarization-magic-angle spinning ~3C NMR spectra obtained from samples of poplar (Populus sp.), oak (Quercus sp.), and silver fir (Abies alba) were examined in this study. The most relevan t peaks were assigned according to the extensive literature in the area, and the differences observed discussed in terms of lignin and cellulose composition: by fixing a lignin reference signal intensity, the eellulose and hemicellulose moieties showed a strong depletion compared to the lignin signals in archaeological wood.
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