Optimization of reaction parameters and characterization of glyoxal-treated poplar sapwood

Abstract

Glyoxal as a non-formaldehyde cross-linking agent was employed with ammonium persulfate as a novel catalyst to improve the dimensional stability and water resistance of poplar sapwood. The effects of various cross-linking parameters (e.g., glyoxal concentration, curing temperature, glycol-to-glyoxal molar ratio and catalyst concentration) on the properties of wood were investigated, and the parameters were optimized. In comparison with the unmodified wood, the glyoxalmodified wood exhibited improved dimensional stability and reduced water uptake. Moreover, the addition of glycol further strengthened the dimensional stability and anti-leaching ability. Modified wood was characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM) and contact angle instrument. IR indicated that the network structure was formed between the agent itself or cross-linking between wood components and glyoxal. SEM revealed the precipitation and filling effect of the cured glyoxal in the cell wall. Contact angle measurement further confirmed the improved hydrophobicity of wood after modification. All the results suggested that the improved dimensional stability and water resistance of the treated wood could attribute to both bulking effect and cross-linking reaction or network structure formed. However, it is not clear whether network structure by glyoxal itself or the cross-linking between the glyoxal and wood components is formed in wood.Y. Yan and Y. Dong have contributed equally to this work.

Enhancement of mechanical and thermal properties of Poplar through the treatment of glyoxal-urea/nano-SiO2

“…4b) 36 and that GU resin was effectively incorporated into the wood. 4b) 36 and that GU resin was effectively incorporated into the wood.…”

“…Glyoxal is very effective in wood modication, able to endow wood with high dimensional stability (ASE up to 68.7%), low water uptake (45.3%) and low leachability (16.2%), as likewise demonstrated in previous research. 14,36 Aer the GU resin synthesized from glyoxal and urea was introduced to the wood, dimensional stability and water resistance decreased in the samples compared to those modied by glyoxal alone especially the anti leachability. These results were likely caused by the poor water resistance of GU resin, which has a large amount of hydrophilic hydroxyl groups.…”

Improving dimensional stability and durability of wood polymer composites by grafting polystyrene onto wood cell walls

“…Wetting behavior on the surface of untreated and treated wood samples was characterized by contact angle measurement using distilled water at 25°C with 40% RH. Previous research informed the apparatus and method used for contact angle measurement on the sample surfaces parallel to the grain . A drop of test liquid (3 µL) was dosed automatically by an auto‐syringe onto each specimen (20 × 20 × 5 mm 3 ) placed on a movable sample table.…”

High‐performance imitation precious wood from low‐cost poplar wood via high‐rate permeability of phenolic resins

“…The wetting behavior of PF resins on the tangential surfaces of wood specimens was characterized by contact angle measurement using an optical contact angles apparatus (OCA 20, DatapPhysics Instruments GmbH, Filderstadt, Germany). The measurement was performed as reported previously . A drop of PF resin (3 μl) was dosed automatically by an auto‐syringe onto each specimen (20 mm × 20 mm × 10 mm), which was placed on a movable sample table.…”