Effect of Phenol Formaldehyde Resin Penetration on the Quasi-Static and Dynamic Mechanics of Wood Cell Walls Using Nanoindentation

Abstract

To evaluate the effects of phenol formaldehyde (PF) resin modification on wood cell walls, Masson pine (Pinus massoniana Lamb.) wood was impregnated with PF resin at the concentrations of 15%, 20%, 25%, and 30%, respectively. The penetration degree of PF resin into wood tracheids was quantitatively determined using confocal laser scanning microscopy (CLSM). The micromechanical properties of the control and PF-modified wood cell walls were then analyzed by the method of quasi-static nanoindentation and dynamic modulus mapping techniques. Results indicated that PF resin with low molecular weight can penetrate deeply into the wood tissues and even into the cell walls. However, the penetration degree decreased accompanying with the increase of penetration depth in wood. Both the quasi-static and dynamic mechanics of wood cell walls increased significantly after modification by the PF resin at the concentration less than 20%. The cell-wall mechanics maintained stable and even decreased as the resin concentration was increased above 20%, resulting from the increasing bulking effects such as the decreased crystallinity degree of cellulose. Furthermore, the mechanics of cell walls in the inner layer was lower than that in the outer layer of PF-modified wood.

Effects of One-Step Hot Oil Treatment on the Physical, Mechanical, and Surface Properties of Bamboo Scrimber

“…The glue layer was able to be clearly observed, and the glue existed in the cell cavity, indicating that the hot oil treatment does not damage the cell wall structure of bamboo parenchyma cells and has little effect on the glue layer. This suggests that oil treatment has no obvious negative influence on the bonding properties of bamboo scrimber [ 14 , 15 ].…”

Investigation of Synthesis Mechanism, Optimal Hot-Pressing Conditions, and Curing Behavior of Sucrose and Ammonium Dihydrogen Phosphate Adhesive

“…As a consequence, many novel bio-based materials have been developed and are expected to be utilized in many fields [5][6][7][8][9][10]. Wood-based materials (such as particleboard [11], plywood [12], oriented strand board [13], and fiberboard [14]) are common in everyday living environments, and are typically fabricated using formaldehyde-based resins to obtain excellent bonding performance [15][16][17]. However, formaldehyde-based resins have been confirmed to emit free formaldehyde during utilization, which is known to negatively affect human health [18,19].…”

Fatigue behavior of beech and pine wood modified with low molecular weight phenol-formaldehyde resin

“…However, Xie et al (2013), in their review of the effect of chemical modification on mechanical properties of wood, pointed out that this is not always the case. Another example from a recent study, Wang et al (2019), investigated properties of elastic modulus, hardness and storage modulus under quasi-static and dynamic mechanical testing by using nanoindentation technique on PFimpregnated Masson pine (Pinus massoniana Lamb.) using different resin concentrations.…”