蔗渣湿压浆纳米孔隙率的改善

Changes in nanoscale porosity by wet pressing pulps from sugarcane bagasse

纳米孔隙率是纤维素进行反应的关键因素,同时纳米孔隙率会受到湿压榨的影响。本研究是探究湿压榨怎样降低蔗渣浆的纳米孔隙率。本研究先使用热液预处理,随后使用160℃碱液(氢氧化钠)或者190℃有机溶剂(乙醇-水溶液)制浆。制浆时间分别为20m in、40m in、60m in、80m in和100min,湿压榨阶段的压强分别为21MPa、43MPa、64MPa、85MPa和107MPa,处理后所得试样采用热力孔隙度来表征,不同湿压榨压力和制浆时间所得到的浆料纳米孔隙率也各自不同。本实验采用量化热孔径定位孔隙率表征所得浆的纳米孔隙率,当湿压榨压力最低(21MPa)时,可以降低绝大部分浆料的纳米孔隙率。与此同时,当湿压榨压力增加到107MPa时,纳米孔隙率会有一定程度的下降。研究发现,依据浆料的纳米孔隙率也可分为可压缩和不可压缩浆料。

Nanoscale porosity is critical for cellulose reactivity and can be detrimentally affected by wet pressing.The present study evaluated how wet pressing reduced the nanoscale porosity of a set of pulps produced from sugarcane bagasse.The pulps were produced using hydrothermal treatments,followed by either 160℃alkaline（sodium hydrothermal） or 190℃ organosolv（ethanolwater） pulping.Pulping times（20,40,60,80,and 100min） and applied pressures in the pressing step（21,43,64,85,and 107MPa）were varied,and the resulting samples had their nanoscale porosity characterized using calorimetric thermoporometry.The lowest applied pressure（21 MPa） collapsed a considerable fraction of the nanoscale porosities.Otherwise,when additional pressure（up to107 MPa） was applied,a much lower reduction in porosity was observed.The findings indicate that nanoscale porosity of pulps can be separated into compressible and incompressible components.