低温作用对马尾松热处理材力学性能的影响

Effect of cryogenic processing on mechanical properties of heat-treated masson pine

以马尾松素材及热处理材为研究对象,测试其经液氮作用48h取出放置室温24h后的抗弯和抗压性能。结果表明：经低温作用后,素材抗弯弹性模量（MOE）和顺纹抗压强度（CSPG）分别增加了8.06%和6.74%,但低温作用对两种力学性质影响不显著（P=0.067～0.182）;热处理材MOE和CSPG基本保持不变;素材与热处理材的延性系数分别增加了26.92%和8.60%。木材分子链上的羟基与水分子的胶结作用可能是导致低温作用后木材力学强度增加的主要原因。

The flexural and compressive properties of untreated and heat-treated Masson Pine were examined before and after the cryogenic processing at-196 °C for 48 h. The results showed that after the cryogenic processing, the modulus of elasticity（MOE） and compression strength parallel to grain（CSPG） of the untreated specimens were increased 8.06% and 6.74%, respectively. However, there were no significant differences in both MOE and CSPG（P = 0.067-0.182）. The mechanical properties of heat-treated wood specimens were almost the same before and after the cryogenic processing. The ductility ratio of untreated and heat-treated specimens increased 26.92% and 8.60%, respectively. The bonding between hydroxyl groups and water molecules of wood may be the main reason for the increase of mechanical strength after the cryogenic processing.