Effect of Lignin on Bamboo Biomass Self-Bonding During Hot-Pressing: Lignin Structure and Characterization

Abstract

To achieve high value-added utilization of lignin extracted from the biorefinery process in the wood composite industry, binderless particle boards were manufactured by bamboo materials combined with alkaline lignin (AL) in various proportions under various hot-pressing conditions. To elucidate the reactivity and chemical transformations of lignin macromolecules during the hot-pressing process, lignin samples were isolated from the corresponding boards and characterized by highperformance anion-exchange chromatography (HPAEC), gel permeation chromatography (GPC), quantitative 31 P-NMR, and 2D-HSQC NMR. The best bonding strength (1.36 MPa) of the binderless particle boards was obtained under the conditions of 180 °C, pressure 5 MPa, and lignin/bamboo mass ratio 0.4. The molecular weight of the lignin samples decreased from 3260 to 1420 g/mol during hot-pressing. The NMR results showed that the contents of β-O-4' and β-β' linkages were reduced and β-5' linkages were increased as the hot-pressing temperature rose. Simultaneously, the percentage of G-type and H-type lignins as well as the content of phenolic OH increased.

Understanding the Mechanism of Self-Bonding of Bamboo Binderless Boards: Investigating the Structural Changes of Lignin Macromolecule during the Molding Pressing Process

“…In other words, the addition of lignin into bamboo particles affects the homogeneity of bamboo particles. However, the addition of isolated lignin in wood enhances the internal bonding strength of binderless boards under mild conditions (180 ºC, 5 MPa) (Li et al 2015). The DTG curves (Fig.…”

Effect of light-delignification on mechanical, hydrophobic, and thermal properties of high-strength molded fiber materials

“…The Light-delignification refers to a certain degree of delignification treatment carried out on the high yield pulp fibers by chemical, biological or other means. In addition to the activation of the fiber surface lignin, it can also retain the lignin fragments falling off the fibers as much as possible so that they can be effectively utilized under the hot-pressing molding process to improve material performance 11 – 13 . Lignin is the rigid hydrophobic polymer.…”

Morphological observation and characterization of the Pseudoregma bambucicola with the scanning electron microscope

“…Phenotypic plasticity is the ability of an organism to exhibit different phenotypes when adapts to a biological or non biological environment, and has the genetic basis. The aphid is susceptible by its own genetic factors and the impact of external environmental factors to show phenotypic plasticity (Lei et al, 2000, Li et al, 2015). In the aphids, the end of beak is nearly triangular, nearly square, short blunt, wedge, Lance shaped and so on, and the end of beak of the P. bambucicola is short blunt.…”