Romanian Academy P. Poni Institute of Macromolecular Chemistry, Department of Physical Chemistry of Polymers, 41A Gr. Ghica Voda Alley, Ro.700487 Iasi, Romania.
Int J Biol Macromol. 2011 May 1;48(4):667-75. doi: 10.1016/j.ijbiomac.2011.02.009. Epub 2011 Feb 22.
In this study the weathering behavior of lime wood (Tillia cordata Mill.) has been examined using FT-IR and 2D IR correlation spectroscopy, which evidenced chemical changes induced by exposure to weathering conditions. It was showed that lignin is most sensitive component to the photodegradation processes as indicated by considerable decreases in the intensities of the characteristic aromatic lignin band at 1505cm(-1) and other associated bands. By 2D correlation spectroscopy has been demonstrated that the moment of CO from carboxyl and acetyl groups in hemicelluloses is changing first, followed by the CC of aromatic skeletal, CO in non-conjugated ketones, carboxyl groups and lactones, absorbed O-H and conjugated C-O groups in quinones. The carbonyl formation corresponded well with lignin degradation, indicating a close relationship between them. Comparing the rate of carbonyl formation and lignin decay clearly showed that the former is remarkably higher than the latter, indicating the formation of carbonyl bands at 1738cm(-1) probably resulted from not only lignin oxidation but also from reactions occurring in other components of the wood. Quinine formation is combined with the decay of aromatic structures and the formation of conjugated carbonyl groups.
在这项研究中，使用傅里叶变换红外光谱（FT-IR）和二维相关红外光谱（2D IR 相关光谱）研究了石灰木（Tilia cordata Mill.）的风化行为，该方法证实了暴露于风化条件下引起的化学变化。结果表明，木质素是对光降解过程最敏感的成分，这表明在 1505cm(-1)处特征芳香木质素带和其他相关带的强度显著降低。通过二维相关光谱证明，半纤维素中羧基和乙酰基的 CO 首先发生变化，随后是芳族骨架的 CC、非共轭酮中的 CO、羧基和内酯、醌中的吸收 O-H 和共轭 C-O 基团。羰基的形成与木质素的降解很好地对应，表明它们之间存在密切关系。比较羰基形成和木质素降解的速率清楚地表明，前者明显高于后者，这表明在 1738cm(-1)处形成的羰基带不仅可能是木质素氧化的结果，而且可能是木材其他成分发生反应的结果。奎宁的形成与芳构化结构的衰减和共轭羰基基团的形成有关。
