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Chemistry and Industry of Forest Products ›› 2022, Vol. 42 ›› Issue (6): 11-16.doi: 10.3969/j.issn.0253-2417.2022.06.002

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Preparation and Properties of Lignocellulosic Nanofibrils Obtained by Polycarboxylic Acid Pretreatments

Huiyang BIAN1,2, Sheng DUAN1, Jin WU1, Liulian HUANG2, Shuangquan YAO3, Hongqi DAI1,*()   

  1. 1. College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China
    2. National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials, Fuzhou 350108, China
    3. School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, China
  • Received:2021-11-25 Online:2022-12-28 Published:2023-01-07
  • Contact: Hongqi DAI E-mail:hgdhq@njfu.edu.cn

Abstract:

Three kinds of lignocellulosic nanofibrils(LCNF) were prepared from miscanthus straw fiber with the treatment using oxalic acid, maleic acid and citric acid under the condition of high-pressure homogenization. The performances of LCNF were characterized by cold field emission scanning electron microscope(FE-SEM), transmission scanning electron microscope(TEM), X-ray diffraction(XRD) analyzer and thermogravimetric(TG) analyzer. The results showed that polycarboxylic acid pretreatment effectively promoted fiber swelling and weaken the bonding force between fibrils, which was beneficial for the dissociation of microfibrils during the high-pressure homogenization process. The acidity became stronger and the fiber hydrolyzed in the pretreatment process was more intensive when the pKa value of carboxylic acid was smaller, resulting in more uniform size of LCNF. Oxalic acid had the minimum pKa value of 1.25 among there polycarboxylic acids, and the minimum average width of the corresponding prepared LCNF was approximately 15.3 nm. Compared with the raw material of miscanthus straw fiber, high-pressure homogenization could weaken the hydrogen bond occurring in microfibrils, which destroyed partial crystalline area and decreased the crystallinity of LCNF. The crystallinity of O-LCNF, M-LCNF and C-LCNF prepared from oxalic acid, maleic acid and citric acid system was 50.4%, 48.2% and 50.0%, respectively. Under the oxalic acid pretreatment system, the obtained(O-LCNF) exhibited the best thermal stability with the maximum weight loss rate temperature of 353.2 ℃.

Key words: lignocellulosic nanofibrils, polycarboxylic acid, pretreatment, property

CLC Number: