New Zealand School of Forestry, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
Carbohydr Polym. 2018 Oct 1;197:1-8. doi: 10.1016/j.carbpol.2018.05.064. Epub 2018 May 23.
Wood (Eucalyptus regnans and Pinus radiata) and paper samples were stretched to different strain levels using a purpose-built tensile test device fitted into a near infrared (NIR) spectrometer while collecting transmission spectra. Consistent spectral changes caused by mechanical strain, assigned to OH stretching bands, were observed for all three sample types. Bands at 6286 ± 5 cm and 6470 ± 10 cm were tentatively assigned to the OH groups connected with the 2OH⋯6O and 3OH⋯5O intramolecular hydrogen bonds of crystalline cellulose Iβ, respectively. Both bands shifted to higher wavenumbers indicating the elongation of the hydrogen bonds. A linear relationship was found between band shifts and mechanical strain. Band shift rates for the 3OH bond were more than twice that of the 2OH bond, consistent with bending of the glycosidic bond. Bending tests showed that the band at around 6286 cm shifted in opposite direction when under tension or compression.
木材（辐射松和蓝桉）和纸张样本使用专门设计的拉伸测试设备在近红外（NIR）光谱仪中拉伸到不同的应变水平，同时收集透射光谱。所有三种样本类型都观察到了由机械应变引起的一致的光谱变化，这些变化被分配到 OH 伸缩带。6286 ± 5 cm 和 6470 ± 10 cm 处的带被暂定分配给与纤维素 Iβ的 2OH⋯6O 和 3OH⋯5O 分子内氢键相连的 OH 基团。两个带都向更高的波数移动，表明氢键的伸长。在带移动和机械应变之间发现了线性关系。3OH 键的带移率是 2OH 键的两倍多，这与糖苷键的弯曲一致。弯曲测试表明，在拉伸或压缩时，约 6286 cm 处的带向相反的方向移动。
