炭化过程中竹材内部形态结构的变化

CHANGE OF INNER MORPHOLOGICAL TEXTURE OF BAMBOO DURING CARBONIZATION

利用扫描电子显微镜技术和压汞法研究了在200～900℃的炭化过程中,竹材的横截面和纵截面的内部形态结构和竹材中原有孔隙结构的变化。结果表明:竹炭具有与原料竹材相似的维管束和基本薄壁组织等内部形态结构,但在高温下纵截面上有明显的形变;在200～600℃的炭化过程中,竹材中孔隙的孔径分布从250～50000nm这一较宽的范围逐渐漂移至较窄的5500～50000nm之间,其中200～400℃之间变化最为显著;在600～900℃,孔径分布基本稳定在5500～50000nm范围内,但在高温下有变宽的倾向。本研究还探讨了炭化过程中竹材内部形态结构的变化规律与竹材炭化机理之间的联系。

Changes of inner morphological texture and porosity structure of bamboo during carbonization have been (investiged) through heat-treatment in the range of 200-900 ℃,by scanning electron microscopy(SEM) and method of mercury adsorption.Generally,all bamboo carbon obtained from various heat-treated temperature(HTT) show similar morphological texture to those of the starting bamboo in terms of fibrovascular bundle and basic thin wall tissue,except obvious deformation of thin walls and fibrobundles of fibrovascular bundle from HTT of 900 ℃.(However),from 200 to 600 ℃,the radius distribution of pores presents the trend to shift gradually from the wider range of 250-50 000 nm of the starting bamboo to the narrower one of 5 500-50 000 nm of bamboo carbon,most significantly in the range of 200-400 ℃.From 600 to 900 ℃,these radius distributions of pores are dominantly distributed in the range of 5 500-(50 000 nm),with a little trend of broadening in the high HTT.Furthermore,the relationship between morphological change and carbonization mechanism of bamboo was also discussed.