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Biomass Chemical Engineering ›› 2022, Vol. 56 ›› Issue (3): 16-22.doi: 10.3969/j.issn.1673-5854.2022.03.003

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Freezing Activation of Wood Fibers and Preparation of Binder-free Boards

Zixu GUO, Han WANG, Mingwei DI, Jianing ZHAO()   

  1. Engineering Research Center of Advanced Wooden Materials, Ministry of Education, Northeast Forestry University, Harbin 150040, China
  • Received:2021-04-30 Online:2022-05-30 Published:2022-05-21
  • Contact: Jianing ZHAO E-mail:jianingzhaonefu@163.com


Sodium hydroxide-polyethylene glycol-urea mixed solution was used to activate wood fiber under freezing, and then the binder-free fiberboard was prepared. By comparing the mechanical properties of binder-free bonding fiberboard, the better freezing activation process of eucalyptus fiber was determined. The freezing activation effect of wood fiber was characterized by FT-IR, XRD, DSC, TG and XPS. The results showed that the better freezing conditions were as follows: the mass ratio of sodium hydroxide, polyethylene glycol, and urea was 7∶4.2∶12, the mass ratio of activator(i.e, the total mass of sodium hydroxide and urea) and wood fiber was 1∶12, the freezing temperature was -15 ℃ and the freezing time was 45 min. The water absorption thickness expansion rate, internal bonding strength, static bending strength, and elastic modulus of the prepared fiberboard increased by 45%, 238%, 177%, and 129% of the performance requirements in GB/T 11718—2009 Medium Density Fiberboard, respectively. The freezing activation treatment could destroy the hydrogen bond between the cellulose in the wood fiber, improve the reaction activity of hydroxyl and increase the number of active hydroxyl, produce new crystals while expanding the cellulose lattice, and reduce the thermal stability of the wood fiber.

Key words: binder-free bonding, freezing activation, wood fiber

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