Utilization of lignin powder for manufacturing self-binding HDF

Abstract

The preparation of self-binding lignocellulosic fibreboards has been investigated. Different high-density fibreboards (HDF) were hot-pressed based on a mixture of grey alder (Alnus incana L. Moench) wood chips processed by steam explosion auto-hydrolysis (SE) and 15% or 25% lignin content from three different industrial sources: softwood kraft lignin (SWKL), soda wheat straw lignin (SoWhStL) and hydrolysis wheat straw lignin (HWhStL). Density, thickness swelling (TS) after immersion in water for 24 h, modulus of rupture (MOR), modulus of elasticity (MOE) and strength of internal bond (IB) of the board samples were determined. The amount (15% or 25%) and moisture content (MC) (18±1% or 5±2%) of the added lignin affected all the tested properties of the HDF except for density. However, the kind of the added lignin affects the obtained fibreboard more significantly compared to the control sample made without an admixture of lignin. In some cases, the tested values were diminished to half. The tested properties of the HDF samples produced with SoWhStL or HWhStL are compatible with standard requirements for medium-density fibreboard (MDF) for general use under dry conditions (EN 622-5, MDF), however, it depends on the lignin amount and MC.

Green Binders for Wood Adhesives

“…The mechanical strength of the evaluated adhesive system was similar to a commercial phenol-resorcinol-formaldehyde (PRF) adhesive reference [113]. Different industrial lignins, such as softwood Kraft lignins, have been evaluated in selfbinding high-density fibreboards, of which some were found to perform well in dry conditions [114]. Lignin has also been blended with other bio-based polymers such as soybean protein and/or chitosan [32,115].…”

Cross-Linked Chitosan as an Eco-Friendly Binder for High-Performance Wood-Based Fiberboard

“…Afterwards, the blended fibers were according to the national standard of the People's Republic of China GB/T11718-2009 under 180°C temperature, 4.0 MPa pressure (unit pressure of fiberboard surface), and 9 min pressing time to form a board with a size of 200 mm × 200 mm × 3 mm. The density of the fiberboard was 0:95 ± 0:02 g/cm 3 . The fiberboard with the same amounts of water (F-W), fiberboard with the same amounts of CS (F-CS), and fiberboard with the same amounts of DHF (F-DHF) as the control groups were prepared by the above same process.…”

“…Formaldehyde-free bio-based adhesives with renewability have been tried to fabricate fiberboard [2], for instance, lignin and its derivatives derived from plants [3,4], plant protein derived from soy and wheat [5][6][7], nanocellulose [8,9], and starch [10,11]. Nevertheless, they have not been widely used in fiberboard manufacturing on account of their complicated preparation processes, relatively weak bonding performance, and water resisting property.…”

Tailoring of oxidized starch's adhesion using crosslinker and adhesion promotor for the recycling of fiberboards

“…Consequently, it is necessary to develop alternative adhesives to replace UF resins, which are suitable for producing high‐quality MDF products with favorable mechanical properties, and more efficient recycling. Although MDFs have been prepared using renewable adhesives, such as lignin and chitosan, starch has good potential as an adhesive for manufacturing MDFs because it is generally less expensive than these other renewable adhesives. Starch has been used for bonding wood since the time of the ancient Egyptians .…”