压缩炭化杨木的微观结构与化学成分

Microstructure and chemical composition of compressed and carbonized poplar

研究压缩、炭化过程中木材结构与化学成分的变化对压缩炭化木的应用有重要意义。利用扫描电镜、扫描电镜X射线能谱和红外光谱分析研究了杨木经压缩、炭化的微观结构和木材的化学成分变化。研究发现:意杨Populus euramericana经过压缩、炭化后,细胞腔变小,胞壁距离减小,胞壁距离最大分别缩小56.94%和53.34%,但细胞壁本身仍然保持了其完整性;心边材各元素的变化趋势一致,炭元素上升,氧元素下降,以边材为例,素材O/C为1.76,压缩、炭化处理后分别为1.65,1.45;杨木在热压和高温炭化过程中,纤维素的降解,使C—H伸缩振动吸收峰强度下降,并发生了一定的位移,半纤维素降解使C O伸缩振动吸收峰强度降低,木质素苯环和酚醚键C—O—C的伸缩振动吸收峰的变化说明木质素也发生了化学反应,炭化后的心材在波数2 853 cm-1附近出现了明显的振动,说明木材内部复杂的化学反应产生了新的化学基团。

The study of microstructure and chemical composition of carbonized wood has an important meaning for its application. Changes in microstructure and chemical composition of compressed and carbonized poplar （Populus euramevicana） were studied using a scanning electron microscope （SEM）, Energydispersive Xray spectrum （EDS） Analysis, and Fourier Transform Infrared （FFIR） Spectroscopy. Results showed that after Poplar was compressed and carbonized, to maintain cell wall integrity the cell cavity and the distance between the cell walls, which reduced 56.94%, 53.34% at maximum, noticeably diminished. Element content in the sapwood and the heartwood varied similarly after hotpressing and after carbonization with carbon content in creasing and oxygen content decreasing. For example, the CoverO ration of untreated wood was 1.76, after compressed and carbonized, the ration reduced to 1.65 and 1.45. Cellulose and hemicellulose degradation led to a reduction in peak absorption intensity for CH and CO during hotrpressin$ and carbonization with some displacement also taking place. In addition, the change in peak absorption intensity for a benzene ring and phenolicether bond illustrated a chemical change in lignin. Thus, after carbonization in the heartwood, the new absorption peak located near the wave number at 2 853 cm1 indicated that during this treatment a complicated chemical reaction had generated new chemical groups. [Ch, 9 fig. 1 tab. 15 ref. ]