文献类型：期刊文献

英文题名：Effect of Thermal History on Mechanical Relaxations of Dry Wood Determined in Tensile Mode at Temperatures from-136°C to 120°C

作者：Li, Zhu[1] Jiang, Jiali[1] Lyu, Jianxiong[1] Zhao, Liyuan[1]

第一作者：李珠

通信作者：Li, Z[1]

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, Beijing, Peoples R China

年份：2025

卷号：75

期号：2

起止页码：121-129

外文期刊名：FOREST PRODUCTS JOURNAL

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001482903500002)】；

基金：Acknowledgments This work was financially supported by the Fundamental Research Funds of the Chinese Academy of Forestry (CAFYBB2023MA019) and the National Natural Science Foundation of China (32401511) . The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

语种：英文

摘要：The influence of thermal history on the viscoelastic behavior of Chinese fir wood (Cunninghamia lanceolata) was investigated in the temperature range between 136 degrees C and 120 degrees C. The storage modulus (E'), loss modulus (E''), and loss factor (tan d) of the radial specimens dried over P2O5 were determined in tensile mode at multiple frequencies ranging from 0.5 to 10 Hz. Results showed that the E' values of specimens were negatively correlated with the measured temperature. Moreover, d-relaxation, c-relaxation, and b-relaxation were detected in the E'' or tan d spectrum. Wood specimens with thermal history exhibited d-relaxation, with a corresponding temperature range of 129.3 degrees C to 107.4 degrees C, which has not been previously reported or discussed. The c-relaxation was also influenced by thermal history; its peak temperature shifted to a higher range. Furthermore, clear differences in the viscoelastic behavior of wood were found between cooling and heating runs. A comparison demonstrated that b-relaxation at approximately 31.9 degrees C to 37.6 degrees C was only observed in the heating run. The b-relaxation peak temperature showed no frequency dependence, but the b-relaxation intensity significantly decreased with increasing frequency. In contrast, both the peak temperature and intensity of d-relaxation and c-relaxation showed significant frequency dependence. The apparent activation energy of d-relaxation and c-relaxation was 37.24 to 49.87 kJ/mol and 59.69 to 74.30 kJ/mol, respectively, which indicated that d-relaxation was attributable to limited torsional vibration of groups in the amorphous wood cell walls.