Ammonium Lignosulfonate Adhesives for Particleboards with pMDI and Furfuryl Alcohol as Crosslinkers

Abstract

Tightening formaldehyde emission limits and the need for more sustainable materials have boosted research towards alternatives to urea-formaldehyde adhesives for wood-based panels. Lignin residues from biorefineries consist of a growing raw material source but lack reactivity. Two crosslinkers were tested for ammonium lignosulfonate (ALS)—bio-based furfuryl alcohol (FOH) and synthetic polymeric 4,4′-diphenylmethane diisocyanate (pMDI). The addition of mimosa tannin to ALS before crosslinking was also evaluated. The derived ALS adhesives were used for gluing 2-layered veneer samples and particleboards. Differential Scanning Calorimetry showed a reduction of curing temperature and heat for the samples with crosslinkers. Light microscopy showed that the FOH crosslinked samples had thicker bondlines and higher penetration, which occurred mainly through vessels. Tensile shear strength values of 2-layered veneer samples glued with crosslinked ALS adhesives were at the same level as the melamine reinforced urea-formaldehyde (UmF) reference. For particleboards, the FOH crosslinked samples showed a significant decrease in mechanical properties (internal bond (IB), modulus of elasticity (MOE), modulus of rupture (MOR)) and thickness swelling. For pMDI crosslinked samples, these properties increased compared to the UmF. Although the FOH crosslinked ALS samples can be classified as non-added-formaldehyde adhesives, their emissions were higher than what can be expected to be sourced from the particles.

Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate

“…The application of lignin in the formulation of adhesives is primarily due to its polyphenolic structure. Thus, lignin may be used in lignin-phenol-formaldehyde resins, where it is applied to partially replace phenol [ 6 , 74 , 75 ]. Additional chemical modification of lignin, such as phenolation and methylolation, can be applied to increase the lignin reactivity to formaldehyde [ 1 , 75 , 76 ].…”

Strong, Reusable, and Self‐Healing Lignin‐Containing Polyurea Adhesives

“…[1] In the past few decades, nearly 65 % of the adhesives have been consumed in wood-based panel industry, [1] however, most of which are non-renewable adhesives derived from petroleum resources such as phenolformaldehyde resin and urea-formaldehyde resin. [2] Nowadays, as the energy shortage problem aggravates, more and more endeavor has been devoted to searching renewable biomassbased wood adhesives. [3] As a new branch of polyurethane materials, polyurea is made from polyisocyanates and amines.…”

Utilization of Lignin from the Waste of Bioethanol Production as a Mortar Additive

“…The rest is sold as a byproduct for fuel or as a mixture or binder in animal feed (Windeisen and Wegener 2012;Yang et al 2015;Zhang et al 2013). One attempt to make use of lignin-containing wastewater is to use it as a wood adhesive or reacting it with bisulfite to produce a lignosulfonate compound that is widely known as an additive in cement, fertilizer, paper coating, and others (Angelini et al 2019;Aro and Fatehi 2017;Hemmilä et al 2019). Thus the bioethanol production process from lignocellulosic materials is expected to produce minimal waste (zero waste) as the wastes are also processed further not to pollute the environment.…”

“…Plasticizers, such as water-soluble lignosulfonates, are often added into the concrete mixture to disperse cement particles to enhance flow-properties while using low water contents (Childs et al 2019;Gupta et al 2017) Lignin consists of molecules of polyphenol compounds that serve as a binding of cells to each other so that it becomes stiff and rigid, but it can reduce its mechanical strength (Tribot et al 2019). Therefore, lignin can be used as adhesive in plywood, composites, and lignosulfonate (Angelini et al 2019;Aro and Fatehi 2017;Hemmilä et al 2019). Lignosulfonate is one of the lignin derivative obtained by sulfonation of lignin, a water-soluble polymer polyelectrolytes.…”