γ射线辐射杉木压缩木材的固定和蠕变(英文)

为了探讨木材压缩变定固定的机理 ,该研究对杉木压缩木材进行γ射线辐射处理 ,射线辐射剂量分别为 0 (作为对照试材 ) ,10 3 ,5× 10 3 ,10 4 ,5× 10 4 ,10 5,5× 10 5,10 6,5× 10 6Gy ,然后测定和讨论了γ射线辐射杉木压缩木材的重量损失率、平衡吸湿含水率 (EMC)、吸湿回复率 (RSA)和吸水回复率(RSW )、绝干状态下和吸湿解吸过程中的蠕变。该研究表明 :γ射线的辐射剂量对杉木压缩木材的重量损失率、EMC、RSA、RSW有重要的影响 ,当辐射剂量超过 10 6Gy后 ,试材的重量损失率和EMC显著增大 ,RSA和RSW显著下降 ;另外 ,随着γ射线辐射剂量的增大 ,绝干状态和吸湿解吸过程中杉木压缩木材的瞬时柔量和蠕变柔量均呈增大趋势 .从该研究结果可以推测 ,当γ射线辐射剂量较大时 ,特别当辐射剂量在 5× 10 6Gy左右时 ,杉木压缩木材的细胞壁中发生了降解反应或非结晶化反应 .而且 ,该研究证明了压缩木材细胞壁主成分发生的降解反应能够使木材压缩变定得到一定程度的固定

Fixation and Creep of Compressed Wood of Chinese Fir Irradiated with Gamma Rays

In order to discuss the mechanisms of permanent fixation of wood compression set, compressed wood of Chinese fir ( Cunninghamia lanceolata ) was irradiated by gamma rays from 60 Co. The irradiation doses were 0 (for match specimens), 10 3, 5 × 10 3, 104, 5 × 104, 105 , 5 × 10 5, 10 6, 5 × 10 6 Gy, respectively. Then the weight loss, the equilibrium moisture content (EMC), the recovery of wood compression set after adsorption (RSA) and the recovery after immersion in water (RSW), as well as the creep behaviour under a dry specimen condition and under an adsorption and subsequent desorption condition were measured and discussed. This re search proves that the doses of gamma irradiation have great effect on weight loss, EMC, RSA, RSW of irradiated compressed wood of Chinese fir. The weight loss and the EMC increase, the RSA and the RSW fall drastically when the irradiation doses exceed 106 Gy. Both the instantaneous compliance and the creep compliance of the irra diated specimens under the two measurement conditions show the general trend of increase with the increase of gamma irradiation doses. It can be deduced that decomposition or decrystallization reactions happen in the wood cell wall at high gamma irradiation doses, especially at doses of around 5 × 106 Gy. In addition, this research proves that decomposition of main components of cell wall of compressed wood will lead to fixation of compression set of wood to a certain degree.