对甲基苯磺酸水解-高压均质法制备多尺度木质纤维素纳米纤丝

Preparation of Multiscale Lignocellulosic Nanofibrils by p-Toluenesulfonic Acid Hydrolysis and High-pressure Homogenization

中文关键词:  对甲基苯磺酸  高压均质  木质纤维素纳米纤丝  残余木质素  杨木化学机械浆

Key Words:p-toluenesulfonic acid  high-pressure homogenization  lignocellulosic nanofibril  residual lignin  poplar chemi-mechanical pulp

中文摘要:

      以杨木化学机械浆为原料，采用对甲基苯磺酸水解-高压均质法制备木质纤维素纳米纤丝（LCNF）；研究对甲基苯磺酸水解过程中木质素脱除规律及残余木质素对LCNF微观形态、尺寸、结晶结构和热稳定性的影响。结果表明，对甲基苯磺酸水解能有效去除木质素，削弱纤维间结合力，有利于高压均质过程中的微纤丝解离分散。与纤维原料相比，LCNF的无定形区遭到破坏，结晶度由43.9%增至66.0%。通过酸水解可以调控残余木质素含量，进而控制高压均质后LCNF的平均宽度，实现多尺度LCNF的制备。LCNF的木质素含量越低，LCNF分散性越好、尺寸越均一。当残余木质素含量为4.89%时，LCNF平均宽度最小（10.6 nm），最大热失重降解温度（T_max）在350~360 ℃。

Abstract:

      Lignocellulosic nanofibrils （LCNF） were prepared from poplar chemi-mechanical pulp by p-toluenesulfonic acid hydrolysis and high-pressure homogenization method. The law of lignin removal during p-toluenesulfonic acid hydrolysis and the effect of residual lignin on the microscopic morphology， size， crystal structure， and thermostability of LCNF were studied. The results showed that p-toluenesulfonic acid hydrolysis effectively removed lignin and weakened the binding force between fibers， which was beneficial for dissociating and dispersing microfibrils in the high-pressure homogenization process. Compared with the raw material， the amorphous region of LCNF was destroyed and the crystallinity increased from 43.9% to 66.0%. The residual lignin content could be regulated by acid hydrolysis， and the average width of LCNF after high-pressure homogenization could be further controlled， achieving preparation of multiscale LCNF. The lower the lignin content in LCNF， the better the dispersion performance of LCNF and the more uniform the size. When the residual lignin content was 4.89%， the average width of LCNF reached the minimum of 10.6 nm， and the maximum thermogravimetric degradation temperature （T_max） was between 350~360 ℃.