UV辐射前后乙酰化木材的化学组分结构变化与微观构造表征

以杨木木粉为试样，进行不同时长的乙酰化处理，利用紫外光加速老化，探讨不同乙酰化度对木材耐光性能的影响，根据FTIR光谱分析试样化学组分特征吸收峰强度的变化规律，建立乙酰化处理时间与木材化学组分变化之间的关系。结果表明：UV辐射前，乙酰化木粉在1 739 cm-1处饱和酯化合物中CO和 1 385 cm-1处乙酸酯基中C—H的特征吸收峰强度均大于原木粉，处理40 min木粉的吸收峰强度最大，增重率最高，木粉的乙酰化效果显著;UV辐射后，乙酰化木粉在1 504 cm-1处木质素中苯环特征吸收峰强度明显大于原木粉，且乙酰化处理40 min木粉的吸收峰强度最大，表明乙酰化处理能够有效抑制木材化学组分的光降解反应，提高木材的耐光老化性能，其中处理40 min的效果最佳;SEM图片显示，乙酰化处理木粉的纤维状表面较原木粉更加均匀，材料粒径更小，乙酰化处理能有效提高木材的稳定性。

Changes in Chemistry Component Structure and Microstructure Characterization of Acetylated Wood Before and After UV Radiation

The poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks’ intensity which belonged to the chemistry components of samples based on FTIR spectra, and the relationship between duration of acetylation and changes of chemistry components was established, The results showed that: Before UV radiation, the characteristic peaks’ intensity of acetylated poplar powder at 1 739 cm-1 which belonged to CO in saturated esters compounds and 1 385 cm-1 which belonged to C—H in acetate were higher than untreated ones’, the poplar powder with 40 min’s acetylation has the highest characteristic peaks’ intensity, highest weight gain rate, remarkable acetylation effect; After UV radiation, characteristic peaks’ intensity of Benzene at 1 504 cm-1 which belonged to lignin of poplar powder was obviously higher than untreated ones’, and characteristic peaks’ intensity of poplar powder with 40 min’s acetylation was the highest, this showed that acetylation could effectively reduce the light degradation of wood chemistry components, in order to improve the lightfastness, especially the poplar powder with 40 min’s acetylation; SEM photos showed that, the fibrous surface of acetylated poplar powder was more smooth and had more narrow particle size than untreated ones’, so acetylation can effectively improve the stability of wood.