文献类型：期刊文献

英文题名：Comparative Study of the Hydrothermal Softening Characteristics of Heartwood and Sapwood

作者：Li, Zhu[1,2] Lu, Jianxiong[1] Cao, Jinzhen[2] Jiang, Jiali[1]

第一作者：Li, Zhu;李珠

通信作者：Jiang, JL[1]|[a0005c4a974b7fbd344a8]蒋佳荔;

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, Hunan Collaborat Innovat Ctr Effect Utilizing Woo, Beijing, Peoples R China;[2]Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing, Peoples R China

年份：2020

卷号：70

期号：3

起止页码：243-248

外文期刊名：FOREST PRODUCTS JOURNAL

收录：;EI(收录号：20204609483810);Scopus(收录号：2-s2.0-85094197536);WOS:【SCI-EXPANDED(收录号:WOS:000592247200001)】；

基金：This research was sponsored by the Fundamental Research Funds of Chinese Academy of Forestry (CA-FYBB2020MA001).

语种：英文

外文关键词：Glass transition - Heating rate - Lignin - Viscoelasticity

摘要：This study was conducted to investigate the hydrothermal softening characteristics of heartwood and sapwood from Catalpa bungei. The viscoelastic properties were investigated by dynamic mechanical analysis (DMA Q800) with a tension and submersion mode. Heartwood and sapwood specimens were tested under water-saturated conditions in the radial and tangential directions. The measured temperature ranged from 25 degrees C to 79 degrees C with three heating rates: 0.5 degrees C/min, 1 degrees C/min, and 2 degrees C/min. The results show that heartwood specimens presented a higher storage modulus (E') and a lower reduction of wood rigidity (Delta E') than sapwood specimens. A difference was also observed in loss modulus (E ''), and the glass transition temperature of lignin in heartwood specimens was nearly 2 degrees C to 3 degrees C lower than that in sapwood specimens. This could be caused by lower lignin content and higher levels of extractives of sapwood in comparison with heartwood. Additionally, a circular arc curve of E' versus E '' was formed in heartwood specimens, irrespective of heating rate. These findings suggest that heartwood presented better hydrothermal softening characteristics than sapwood. Compared with the tangential specimens, the radial specimens revealed higher E' and lower Delta E', indicating that the radial specimens were less influenced by hydrothermal treatment.