Age is an important factor that dictates bamboo’s mechanical properties. In Japan, bamboo plants aged 3–5 years are selected for use as materials because of their robustness and decorative or craft-friendly characteristics. In this study, the age-dependent and radial sectional differences in bamboo’s dynamic viscoelastic properties in relation to lignin structural variation, were evaluated. We used Phyllostachys pubescens samples at the current year and at 1.5, 3.5, 6.5, 9.5, 12.5, and 15.5 years of age. There was a clear age dependence in the peak temperature of tan δ and in the yield of thioacidolysis products derived from β-O-4 lignin structures. The highest peak temperature tan δ value was detected in 3.5-year-old bamboo, which contained the highest amount of the thioacidolysis products. Moreover, tan δ’s peak temperature was always higher on the outer side, and the ratio of S/G thioacidolysis products was always higher on the inner side of bamboo plants of all ages. These results suggest that changes in bamboo’s thermal softening properties from aging are caused by the maturation and degradation of lignin in bamboo.

中文翻译：

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竹茎的动态粘弹性特性的年龄相关和径向截面差异及其与木质素结构的可能关系

年龄是决定竹子机械性能的重要因素。在日本，由于其坚固性，装饰性或工艺友好性，选择了3至5岁的竹子作为材料。在这项研究中，评估了与木质素结构变化有关的竹动态粘弹性的年龄相关和径向截面差异。我们在当年以及1.5、3.5、6.5、9.5、12.5和15.5岁时使用了毛竹毛虫样品。tanδ的峰值温度和衍生自β-O-4木质素结构的硫代酸解产物的产率均具有明显的年龄依赖性。在3.5岁的竹子中检测到最高的峰值温度tanδ值，该竹子中的硫代酸解产物含量最高。此外，各个年龄段的竹子植物的外侧，tanδ的峰值温度始终较高，内侧的S / G硫代酸解产物的比率始终较高。这些结果表明，老化引起的竹子热软化特性的变化是由竹子中木质素的成熟和降解引起的。