Mechanical Properties and Formaldehyde Release of Particleboard Made with Lignin-Based Adhesives

Abstract

The aim of this research was to evaluate the potential of magnesium lignosulfonate as adhesive in particleboard manufacturing. Diphenylmethane diisocyanate (PMDI) between 1% and 3% and glucose (1% of the lignosulfonate content) were added as potential cross-linkers in the adhesive formulations. Mixed beech and spruce wood, 30% beech wood and 70% spruce wood, were employed for the configuration of the panel structure. The density, mechanical properties and formaldehyde emission of single-layer particleboard were investigated. Spectroscopic analysis (FTIR) revealed structural changes brought by oxidation that may indicate depolymerization by the splitting of C-O-C bonds and formation of carbonyl groups. Mechanical properties were improved, and the highest average values were recorded for panels having as adhesives oxidized lignin with cross-linkers as follow: 15 N/mm2 (MOR), 3320 N/mm2 (MOE) and 0.48 N/mm2 (IB). The density profile presented higher values for faces in case of oxidized lignin panels. Changes were observed for oxidized lignin with cross-linker panels wherein the core had higher values. The results showed that the panels manufactured with adhesives composed of oxidized lignosulfonate (20% of the dried wood particles weight) and the addition of PMDI and glucose in various percentages have a positive influence on their formaldehyde release and mechanical properties requested by EN 312 (2004) standard.

Sieving and hydrothermal pre‐treatments for preparing ultra‐high mechanical strength particleboard

“…At this time, the stiffness and MOR of the particleboards increased, and the internal bonding strength decreased. The higher surface density and lower inner density resulted in better bending strength 30 . Therefore, the static bending strength of all RPs samples was striking higher than many wood‐based panels.…”

“…Many straw‐based particleboards with weak bonding strength were owing to the low rigidity of materials, which was usually blended with wood particles to improve the strength 17 . MOR and IBS of RPs were obviously higher than those of many other non‐wood‐based particleboards and even particleboards made from wood 30–33 . The mechanical strength of particleboards is not only affected by the structure of biomass, but also by the formation process.…”

Renewable Tannin-Based Adhesive from Quebracho Extract and Furfural for Particleboards

“…In particleboard with a density of 650 kg m −3 bonded by oxidized base lignin resin, the authors registered an internal cohesion strength of 0.10 MPa, while the modulus of elasticity and modulus of rupture were respectively 1847 and 8.1 MPa. Adding different amounts of isocyanate from 1 to 3%, increases of up to 0.40, 2900, and 15 MPa, respectively, were observed [25].…”

“…Chen et al [23] and El Mansouri et al [24], for instance, exploited modified lignin for particleboard manufacturing, obtaining boards respecting the EN 312 (2010) for P2 requirements. In addition, magnesium sulfonate lignin added with a low amount of isocyanate was applied to obtain stable formaldehyde-free boards [25]. In order to limit the use of hazardous substances such as isocyanates as much as possible, appealing alternatives are proposed by exploiting the polyphenolic character of lignin.…”

Effect of Hot-Pressing Temperature on the Properties of Eco-Friendly Fiberboard Panels Bonded with Hydrolysis Lignin and Phenol–Formaldehyde Resin

“…However, it is mainly burned in production facilities to obtain thermal energy and partially regenerate some chemical reagents. Organosolv lignin is obtained in very small amounts, and when using lignosulfonates as binders in the production of wood-based panels, significant deterioration of the waterproof properties of the materials is observed [ 14 , 15 , 16 ]. Technical hydrolysis lignin is obtained as a residual product during acid or enzymatic biomass hydrolysis to sugars to produce bioethanol or other valuable raw materials [ 17 ].…”