Abstract

Transformations of pine wood during exposure to ozone were studied. The content of lignin and cellulose in the cellulose-containing material (CCM) from ozonated wood was determined. The polymerization degree (PD) of cellulose from CCM was determined. The CCM samples were examined by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and X-ray diffraction (XRD) analysis. HPLC analysis of water-soluble lignin ozonolysis products was performed. Wood ozonation leads to lignin destruction; 40–42% delignification degree is achieved. The destruction of aromatic components is confirmed by DRIFT spectra. A decrease in the intensity of skeletal vibrations of aromatic ring at 1511 and 1598 cm^–1, bands at 1662 cm^–1, and an increase in the intensity of stretching C=O vibrations of lignin and hemicelluloses (HCs) at 1736 cm^–1 were observed. The stoichiometric ratio of the amount of absorbed ozone and the destroyed guaiacyl units, as well as the composition of water-soluble products, shows that ozonolysis is the main mode of wood lignin destruction. The XRD data and a decrease in PD of cellulose show that, in addition to lignin, HCs and amorphous cellulose are also destroyed during ozonation. It has been found that the region of ozone specific absorption ≤1.5 mmol O₃/g corresponds to the most efficient destruction of lignin with the lowest degradation of cellulose fiber.

中文翻译：

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臭氧分解脱木素过程中松木结构的降解

摘要

研究了松木暴露于臭氧过程中的转变。测定来自臭氧化木材的含纤维素材料（CCM）中木质素和纤维素的含量。测定了来自CCM的纤维素的聚合度（PD）。通过漫反射红外傅里叶变换（DRIFT）光谱和X射线衍射（XRD）分析检查了CCM样品。进行了水溶性木质素臭氧分解产物的HPLC分析。木材臭氧化导致木质素破坏；达到40-42％的脱木素度。通过DRIFT光谱证实了芳族组分的破坏。1511和1598 cm ^–1处芳环的骨架振动强度降低，1662 cm ^–1处的带强度降低，并且观察到在1736 cm ^–1处，木质素和半纤维素（HCs）的C = O振动拉伸强度增加。臭氧吸收量和被破坏的愈创木单位的化学计量比以及水溶性产品的组成表明，臭氧分解是破坏木质素的主要方式。XRD数据和纤维素PD的降低表明，除木质素外，HCs和无定形纤维素在臭氧化过程中也被破坏。已经发现，臭氧比吸收≤1.5mmolO ₃ / g的区域对应于木质素的最有效破坏，而纤维素纤维的降解最低。